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Community => Gigs and Collaborations => Topic started by: boelle on Aug 25, 2012, 07:15 pm

Title: Opensource DIY clothes dryer
Post by: boelle on Aug 25, 2012, 07:15 pm
I have an old condenser style dryer and was thinking of replacing the control with something arduino based...

I could hack something just for myself and make a showoff on youtube and not share like many do, but why be an "arse"?

So I thought maybe there are others that want's to do the same and maybe even in the end do something like a kit for those not so comfortable with building boards?

Anyways my initial thoughts are:

Must be able to work with both a condenser and normal type dryer. The difference is that the normal type just dumps the heated air (big waste... imho) where the condenser re-circulate the heated air through a condenser unit --- Which more or less can be descriped as car radiator, that keeps the internal airflow seperate from the external --- and back to the clothes. Now a 2nd blow whell takes room air and blows more cool air through the condenser. This cools down the damp air on the other side and the water condenses and runs out a small tube or in a collector. (my machine is the later one)). Some say that they are damaging to the health but i would say that is only true if the condenser is coated with chemicals.

both types have a sensor that messures how much water is in the air so not that much trouble there, they also have a way to messure if the filter is full (dont know how.... airflow?). They also both have a single motor that turns both the drum and blow wheels. and they also have a heating element.

Now where i want to make the first improvement are control over the heating element. Must be PID control so that the heat can be controlled precise and without to much over or under shoot. Maybe do the same with the motor that turns the drum so that people are able to experiment with both heat level and run time. (my dishwasher has an eco program that runs a lower temp but the cycle are longer) this could maybe in the end be cheaper?

i have looked at this link: http://thecustomgeek.com/2011/06/18/jos-open-source-menu-interface-for-arduino/

so the framework is more or less done... its more or less the cycle itself that i need some help with.... dinner time here in denmark so will return later in the evening

my birthday is up so an arduino mega is on the wishlist, i know it might be overkill but it will be used as dev platform and smaller board picked in the end
Title: Re: Opensource DIY clothes dryer
Post by: boelle on Aug 25, 2012, 11:13 pm
to control the heating i came across this: http://www.over-engineered.com/projects/sous-vide-pid-controller/#more-69

not overly hard to use, at least not the hardware side, its more the software side that troubles my mind, what part of this code is needed to just control a heating element with a dallas chip? http://www.over-engineered.com/wp-content/uploads/TemperaturePID.pde

my "loose" idea is to make some preset cycles (target humidity, temp etc.) and put them in the menu sketch i linked just above... but... when i click a cycle the screen should not just simply say that is beeing done, but change to a screen that shows the target specs and what the current status are...
Title: Re: Opensource DIY clothes dryer
Post by: boelle on Aug 25, 2012, 11:16 pm
doooh.... forgot another thing... not a first on the list item but,

i want at some point add a strain gauge so that the controller can messure the whight of clothes so that the machine are not overloaded

and another nice to have could be able to messure how much power is beeing used here and now.. and how much total for the cycle... maybe have a total somewhere else... maybe a menu item that just shows how much in total... just thoughts thou... not important right now
Title: Re: Opensource DIY clothes dryer
Post by: boelle on Aug 25, 2012, 11:19 pm
and yes... i got a pm from a person offering services... the idea of this thread is create an controller that everyone can use and hack...

2nd idea is that if enough interest i could make a kit... but everything has to be opensource for everyone to copy... when i get to the hardware i will publish eagle files ( i use the free version so they will be limited in size and possible more than one board are needed)
Title: Re: Opensource DIY clothes dryer
Post by: CrossRoads on Aug 26, 2012, 06:44 pm
What are your plans for controlling gas as the heat source?
I personnally have no plans to modify my gas heated dryer nor to get an electric heating element dryer.
I find what fits in the washer also fits in the dryer.
Title: Re: Opensource DIY clothes dryer
Post by: boelle on Aug 26, 2012, 10:05 pm
yeah, living here in europe (denmark in fact) i have totally forgotten about the gas driven ones, but now you mention i think that is a no-go for now (sure it's do able but require some more thinkering to keep it safe)

if your comment about what fits in the washer also fits in the dryer is meant like they are almost the same i would agree

the main idea for me at least was something that could allow me better control over the use of heat so that there was not so much over/under shoot of the heat and also allow me control over how the clothes are dryed, ie use lower heat but run longer would save some money since it does not require much to run the drum.. of course there is some croos point where higher heat would be a benefit

but once a dryer is done there is not far to control the washer, but maybe bigger savings can be done here..

and also at least in europe its common know that if you select a cycle that should run at 60 degree C it has been messured many times that the cycle runs much lower. not a big deal would many say but when it comes to killing bed bugs etc its important that you can trust the temp....

also with an arduino you can do a lot more like remote monitor and collect data on how much water etc has been spend... even automatic dispensing of soap and fabric softner
Title: Re: Opensource DIY clothes dryer
Post by: boelle on Aug 29, 2012, 03:17 am
so i downloaded the code for the menu here... http://www.thecustomgeek.com/files/JOS_TFT_Touch_ALPHA_LS.pde

i gives a bunch of complie errors, i think because the code is not made for the newest version of the lib's but not sure where or what to correct

can somebidy point me in the right direction?

Code: [Select]
sketch_aug29a:47: error: 'TFTLCD' does not name a type
sketch_aug29a.cpp: In function 'void setup()':
sketch_aug29a:134: error: 'tft' was not declared in this scope
sketch_aug29a.cpp: In function 'void loop()':
sketch_aug29a:234: error: 'tft' was not declared in this scope
sketch_aug29a:240: error: 'tft' was not declared in this scope
sketch_aug29a:246: error: 'tft' was not declared in this scope
sketch_aug29a:252: error: 'tft' was not declared in this scope
sketch_aug29a:258: error: 'tft' was not declared in this scope
sketch_aug29a:271: error: 'tft' was not declared in this scope
sketch_aug29a:277: error: 'tft' was not declared in this scope
sketch_aug29a:283: error: 'tft' was not declared in this scope
sketch_aug29a:289: error: 'tft' was not declared in this scope
sketch_aug29a:295: error: 'tft' was not declared in this scope
sketch_aug29a:308: error: 'tft' was not declared in this scope
sketch_aug29a:314: error: 'tft' was not declared in this scope
sketch_aug29a:320: error: 'tft' was not declared in this scope
sketch_aug29a:326: error: 'tft' was not declared in this scope
sketch_aug29a:332: error: 'tft' was not declared in this scope
sketch_aug29a:345: error: 'tft' was not declared in this scope
sketch_aug29a:351: error: 'tft' was not declared in this scope
sketch_aug29a:357: error: 'tft' was not declared in this scope
sketch_aug29a:363: error: 'tft' was not declared in this scope
sketch_aug29a:369: error: 'tft' was not declared in this scope
sketch_aug29a:382: error: 'tft' was not declared in this scope
sketch_aug29a:388: error: 'tft' was not declared in this scope
sketch_aug29a:394: error: 'tft' was not declared in this scope
sketch_aug29a:400: error: 'tft' was not declared in this scope
sketch_aug29a:406: error: 'tft' was not declared in this scope
sketch_aug29a:419: error: 'tft' was not declared in this scope
sketch_aug29a:425: error: 'tft' was not declared in this scope
sketch_aug29a:431: error: 'tft' was not declared in this scope
sketch_aug29a:437: error: 'tft' was not declared in this scope
sketch_aug29a:443: error: 'tft' was not declared in this scope
sketch_aug29a:456: error: 'tft' was not declared in this scope
sketch_aug29a.cpp: In function 'void clearcenter()':
sketch_aug29a:565: error: 'tft' was not declared in this scope
sketch_aug29a.cpp: In function 'void clearsettings()':
sketch_aug29a:579: error: 'tft' was not declared in this scope
sketch_aug29a.cpp: In function 'void homescr()':
sketch_aug29a:585: error: 'tft' was not declared in this scope
sketch_aug29a.cpp: In function 'void menu1()':
sketch_aug29a:594: error: 'tft' was not declared in this scope
sketch_aug29a.cpp: In function 'void menu2()':
sketch_aug29a:603: error: 'tft' was not declared in this scope
sketch_aug29a.cpp: In function 'void menu3()':
sketch_aug29a:612: error: 'tft' was not declared in this scope
sketch_aug29a.cpp: In function 'void menu4()':
sketch_aug29a:621: error: 'tft' was not declared in this scope
sketch_aug29a.cpp: In function 'void menu5()':
sketch_aug29a:630: error: 'tft' was not declared in this scope
sketch_aug29a.cpp: In function 'void settingsscr()':
sketch_aug29a:639: error: 'tft' was not declared in this scope
sketch_aug29a.cpp: In function 'void showsleep()':
sketch_aug29a:800: error: 'tft' was not declared in this scope
sketch_aug29a.cpp: In function 'void blbar()':
sketch_aug29a:923: error: 'tft' was not declared in this scope
sketch_aug29a:926: error: 'tft' was not declared in this scope
sketch_aug29a.cpp: In function 'void ant()':
sketch_aug29a:931: error: 'tft' was not declared in this scope
sketch_aug29a.cpp: In function 'void boxes()':
sketch_aug29a:934: error: 'tft' was not declared in this scope
sketch_aug29a.cpp: In function 'void signal()':
sketch_aug29a:942: error: 'tft' was not declared in this scope
sketch_aug29a.cpp: In function 'void signalact()':
sketch_aug29a:962: error: 'tft' was not declared in this scope
sketch_aug29a.cpp: In function 'void drawhomeicon()':
sketch_aug29a:982: error: 'tft' was not declared in this scope
sketch_aug29a.cpp: In function 'void drawhomeiconred()':
sketch_aug29a:994: error: 'tft' was not declared in this scope
sketch_aug29a.cpp: In function 'void clearmessage()':
sketch_aug29a:1006: error: 'tft' was not declared in this scope
sketch_aug29a.cpp: In function 'void drawbatt()':
sketch_aug29a:1011: error: 'tft' was not declared in this scope
sketch_aug29a:1015: error: 'tft' was not declared in this scope
sketch_aug29a:1018: error: 'tft' was not declared in this scope
Title: Re: Opensource DIY clothes dryer
Post by: CrossRoads on Aug 29, 2012, 06:10 am
Do you have these 2 libraries in your library folder?

#include "TFTLCD.h"
#include "TouchScreen.h"
Title: Re: Opensource DIY clothes dryer
Post by: boelle on Aug 29, 2012, 12:11 pm
yep... or else it would have reported them missing :-D
Title: Re: Opensource DIY clothes dryer
Post by: boelle on Aug 29, 2012, 12:59 pm
the author have released a new version after i hit the bed...

now the error is reduced to:
Code: [Select]
sketch_aug29a.cpp:10:3: error: #error "For use with the shield, make sure to #define USE_ADAFRUIT_SHIELD_PINOUT in the TFTLCD.h library file"

in his post here: http://thecustomgeek.com/2012/08/28/jos-updated/ (http://thecustomgeek.com/2012/08/28/jos-updated/) he says to uncomment the line but the sketch says it should be defined... the sketch is here: https://github.com/jersagfast/JOS---TFT-Menu-System/blob/master/JOS_Touch_15.ino (https://github.com/jersagfast/JOS---TFT-Menu-System/blob/master/JOS_Touch_15.ino)

but non the less its a lot closer, once i get it working my first step is to insert a wifi config screen  XD
Title: Re: Opensource DIY clothes dryer
Post by: boelle on Aug 29, 2012, 01:54 pm
quick fix was to uncomment the line in Adafruit_TFTLCD.h and put a "1" at the end of the line

of course this might not be correct but at least it can compile
Title: Re: Opensource DIY clothes dryer
Post by: boelle on Sep 04, 2012, 05:12 pm
so i got the 2560 mega and a redfly (wifi) shield and so far managed to get a simple sketch going (look below)

i have an approx idea on how to sticth in my cycles (just a few) for the dryer, but would that be wrong if i later want to add a touch screen?

https://github.com/pkulchenko/DHCPLite/blob/master/examples/DHCPLite/RedFly/RedFly.pde
Title: Re: Opensource DIY clothes dryer
Post by: Constantin on Sep 04, 2012, 05:50 pm
Allow me a couple of comments based on tearing about 10+ dryers down for work. These suggestions are by no means all-encompassing, and my primary concern would be safety. It goes without saying that modifying a 5kW device is something that should be done VERY carefully. Based on the usual 230V power supply in the US for electric dryers, that's about 25 amperes, I suggest having a fire extinguisher on hand and to have the whole assembly downstream from a manual disconnect switch that is rated for the current you're playing with (i.e. 20+ amps). Do NOT rely on the circuit breaker to protect you.

Unless you have the right background, I would hire an experienced Electrical Engineer (i.e. someone who has designed similar circuits) to guide with the design and a good electrician to implement it. Have them study the schematics that are enclosed with the dryer. They are usually hidden inside the dryer inside a plastic baggie. The manual may mention the location.

Study the main PCB also. The relays that are used there will be a good guide towards the MINIMUM relay capacity you'll have to consider for your board / control system. You may need some very fat traces to carry some of the high currents involved or (better yet) use relays that feature 0.25" quick connect terminals for the load switching (preferable, IMO).

As for modulating heat control, if you want to go down this path I'd suggest the use of a 40A SSR (Triac-based) with a big heat sink - see the spec sheets re: the heat sink needs as a function of current and perhaps mount the heat sink in the path of incoming air to help cool it or add a supplemental box fan to keep it cool. I have used the PID library hosted here (http://arduino.cc/playground/Code/PIDLibrary) for my reflow oven. Works great.

If your dryer has a separate motor for air flow and drum rotation, I would consider going with a dual-channel SSR, that allows you to modulate the air flow as well as the heater any way you like. I would not mess with the induction motor driving the drum. Keep that on a a simple relay, on/off.

I would also mount multiple DS18B20s around the dryer to shut it off if there is a problem (i.e. SSR heat sink, exit air temperature for the drum, air flow motor, housing around the heaters, etc.). I would also confirm air flow and stop the dryer if there is a problem. The induction motor that usually drives both the fan and the drum may have a centrifugal switch that you could use for that purpose.

Let me re-iterate: Unless you know what you're doing, do not attempt this project by yourself. The voltages and currents involved are sufficient to potentially cause significant physical damage, injury, or even death. Hire experienced help to review what you want to do before implementing it with experienced help. The cost of doing so will be significantly less than the potential trouble you can get yourself or your loved ones into.
Title: Re: Opensource DIY clothes dryer
Post by: boelle on Sep 05, 2012, 10:59 pm
I'm based in Europe and my dryer is a 1 phase unit so it takes no more than 2300Kw all included (also the rating of the fuse in breaker/fuse panel). Also here it's required to have a earth leakage relay, that if the current that goes in the relay does not match what goes out disconnects everything from the outside, it only allows 20 miliamps of leakage max. in practical terms it means that if current goes through me to ground the relay will cut. and all stuff like dryers and washers are required to be grounded. anyway i would never touch anything thats live if i can avoid it. and if needing to messure something good commons sense is half the safety

I do have the background, been working 1 year as an electrician and do have about 12 courses in electronics. The Schematics are not included... but that not what worries me, i can draw it in a few hours with the dryer taken apart and a multimeter.

For the high loads, in fact both the heating element and motor that rotates the drum its my plan to use solid state relays or triac's. I have in mind those kinds that have either screw terminals or spade connectors depinding on what is used in my unit. 40A seems a bit overkill compared to that my system is 10A max.. but maybe go for a 20A would be the choice. since my dryer is a condensing type it has 2 airways.. one internal and one that just takes room air and blows it through the condenser, the output from here is barely any hotter than what it takes in and seems a good place for airflow over the heatsink. i agree to not mess with drum rotation, makes no sense to alter it.

and the idea with  multiple temp sensors is not bad either, at least i know there has to be a certain difference between room temp and the temp in the drum before the condenser operates, the higher difference the faster you are done but also you use more electricity. i know that my dryer has a resetable thermofuse if it gets to hot. i only need to figure how it detects a full filter.


my biggest problem is coding, no problem in finding code here and there for what i want, its more stitching it together that is the main issue.
Title: Re: Opensource DIY clothes dryer
Post by: boelle on Sep 05, 2012, 11:10 pm
Hmm.. thought i would do draft on inputs and outputs i plan to use

inputs:
--------
room temp
triac temp
drum temp
humidity sensor - most of my "planned" cycles target a humidity set point and starts a cool down period after that.
water tank full - cant decide if i should just have a simple full or upgrade to a load sensor / strain gauge to tell how full
current sensor - nice to know how much electricity used both per cycle and in total.
airflow sensor - to detect if filter is full and if possible how full

outputs:
----------
drum rotation
drum direction
heat
(airflow)
Title: Re: Opensource DIY clothes dryer
Post by: retrolefty on Sep 05, 2012, 11:17 pm
I would think the single most efficient control algorithm would be to use an internal humidity sensor to tell the controller that the cloths are dry enough now and to cut the heat source (gas or electric) and start the tumble cooling cycle. I believe that there are dryers that have that control option available all ready?

Title: Re: Opensource DIY clothes dryer
Post by: boelle on Sep 05, 2012, 11:23 pm
most work that way...

but what could improve is variable heat source where most dryers operate on a simple on/off and that will cause some overshoot which is a waste of energy.

adding an arduino also allows for custom cycles. one of my fav's will be a cycle that targets on humidity but use lower temps, this will of course result in a longer cycle but will save on the bill. of course you have to judge time used against heat used... why i included a current sensor so that electricity used can be messured...

again its mostly stitching code together that are my biggest issue in this project.
Title: Re: Opensource DIY clothes dryer
Post by: retrolefty on Sep 05, 2012, 11:32 pm

most work that way...

but what could improve is variable heat source where most dryers operate on a simple on/off and that will cause some overshoot which is a waste of energy.

Why would overshoot/undershoot be a waste of energy. Is not all the heat energy generated directly going into the drying of the material? As long as you are not continuing to send heat into the material that is already 'dry enough' I don't see where the 'waste' is? Too much heat, time to 'dry enough' shortened, too little heat, time to 'dry enough' takes a little longer, no net change on total heating BTU consumed used to reach the it's 'dry enough' setpoint.

adding an arduino also allows for custom cycles. one of my fav's will be a cycle that targets on humidity but use lower temps, this will of course result in a longer cycle but will save on the bill. Why would this save energy consumed, it should take the same amount of total BTUs to remove xx amount of moisture from the material because it's a heat/time product equation? of course you have to judge time used against heat used... why i included a current sensor so that electricity used can be messured...

again its mostly stitching code together that are my biggest issue in this project.
Title: Re: Opensource DIY clothes dryer
Post by: Constantin on Sep 06, 2012, 01:33 am

I'm based in Europe and my dryer is a 1 phase unit so it takes no more than 2300Kw all included (also the rating of the fuse in breaker/fuse panel).


I presume you meant 2300W, not kW. Otherwise, you'd likely have to open a new sub-station in your neighborhood.

I'm surprised that the circuits in the EU are limited to 10A for clothes dryers. In the US, we have to run a different kind of wiring (three or four conductor, heavy duty) to dryer outlets, whose plugs can make standard UK plugs blush with envy. I would not rely on a GFCI to protect you. At least for testing purposes I would have a manual fuse and a disconnect switch. But that's me.

I do have the background, been working 1 year as an electrician and do have about 12 courses in electronics. The Schematics are not included... but that not what worries me, i can draw it in a few hours with the dryer taken apart and a multimeter.


Thanks for re-assuring me that you know what you're doing. Having taken a bunch of these (and many other) appliances apart, I suggest you find a copy of the schematics if you can. Perhaps the OEM can send you a copy. It will make your life a lot easier. Let me give you an example: I recently attached a SSR to a toaster oven circuit and had a diode interfere with it. The diode was not obvious because the OEM had included no diagram with the toaster oven.

For the high loads, in fact both the heating element and motor that rotates the drum its my plan to use solid state relays or triac's. I have in mind those kinds that have either screw terminals or spade connectors depinding on what is used in my unit.


My suggestion would be to use a Triac with 0.25" quick connects. The friction fit is almost impervious to the inevitable vibrations of the dryer as it operates.

40A seems a bit overkill compared to that my system is 10A max.. but maybe go for a 20A would be the choice. since my dryer is a condensing type it has 2 airways.. one internal and one that just takes room air and blows it through the condenser, the output from here is barely any hotter than what it takes in and seems a good place for airflow over the heatsink. i agree to not mess with drum rotation, makes no sense to alter it.


Seems reasonable. For the record, I meant not to alter the drum speed. I agree that changing the drum direction is unlikely to have any benefit either. Hard to do, unless you have the right motor in there to start with.

and the idea with  multiple temp sensors is not bad either, at least i know there has to be a certain difference between room temp and the temp in the drum before the condenser operates, the higher difference the faster you are done but also you use more electricity. i know that my dryer has a resetable thermofuse if it gets to hot. i only need to figure how it detects a full filter.


The thermofuse blows if the temperature near the coils gets too hot. That temperature is a function of air flow. Once the air flow is impeded by a clogged filter, the fuse will hence trip. Down by the actual blower motor (which typically sucks the air through the heater, followed by the drum before exhausting it) you should find at least one more thermal switch or sensor for the less expensive models. Once the exhaust air reaches a certain level, the dryer knows that the clothes are almost dry, runs a bit more, and shuts off.

More expensive dryers will attempt to divine clothing wetness through a variety of additional means.
Title: Re: Opensource DIY clothes dryer
Post by: Constantin on Sep 06, 2012, 01:37 am

I would think the single most efficient control algorithm would be to use an internal humidity sensor to tell the controller that the cloths are dry enough now and to cut the heat source (gas or electric) and start the tumble cooling cycle. I believe that there are dryers that have that control option available all ready?


Every unit I saw did not measure humidity directly. Either capacitive sensors, temperature, etc. I presume fouling has to do with it. The nice aspect of the "bar" sensors typically found in the back wall of dryers is that they cannot foul easily. How accurate they are is another question. However, you can supplement that info with exit temperature info to hopefully not over- or under-dry too much.
Title: Re: Opensource DIY clothes dryer
Post by: Constantin on Sep 06, 2012, 01:55 am

Why would overshoot/undershoot be a waste of energy. Is not all the heat energy generated directly going into the drying of the material? As long as you are not continuing to send heat into the material that is already 'dry enough' I don't see where the 'waste' is? Too much heat, time to 'dry enough' shortened, too little heat, time to 'dry enough' takes a little longer, no net change on total heating BTU consumed used to reach the it's 'dry enough' setpoint.


Allow me to disagree a bit. This is not a closed system. If you control the input into the dryer by monitoring the exhaust temperature, you can limit the excess heat being exhausted to atmosphere (in the case of dryers with flue pipes) or the house (in the case of condensing dryers). You also have to watch that exit temperature for the dryers typically used in the US to eliminate the chance of condensation inside the flue duct, even if you have a stainless duct that has been designed to drain. In a condensing dryer, you presumably want temperatures closer to condensation to help condense the latent heat out.

Additionally, there are benefits to longer drying cycles per the DOE or IEC test procedure. Since the test procedures prescribe a relatively dry room, you can benefit from the "dry" air being sucked through the appliance carrying off moisture without having to heat the air. Heating simply drives off the water faster.

Over-drying results in clothes that are no drier than they could be (i.e. "bone dry" is the limit) but lots of heat being used. In the US, that usually entails the excess heat being vented to atmosphere, in the EU, that eat is "recycled" into the home when using electric condensing dryers. In the wintertime, there is a marginal benefit, in the summertime, it just adds to the heat load of the house. Additionally, over-drying is bad for clothes.
Title: Re: Opensource DIY clothes dryer
Post by: retrolefty on Sep 06, 2012, 02:17 am
Quote
Additionally, over-drying is bad for clothes.


That we agree on. I'm just saying if you have an accurate sensing method for when the cloths are actually 'dry enough' then worrying about having more precise temperature control, say a thermostat switch Vs a full P&ID controller, I don't see any benefit in the added complexity and expense. And what drying temperature to operate at Vs the 'best' time duration to dry seems to be a pretty constant product (total BTU consumed per drying cycle needed to dry the cloths to the 'dry enough' state) in my thinking.

The whole waste heat recovery thing is a different additional animal and is not what I was talking about. Certainly any method of heat recover and recycling will pay off because it would allow the 'dry enough' time to happen faster vs using no waste heat recovery/recycling. If there is other external uses for the waste heat instead of recycling via a air intake heat exchanger, then the possible savings are external, but still real and useful, but doesn't effect what control algorithm the dryer should use.

Bottom line I was trying to make is if one can indeed actually measure accurately when the load has reached a 'dry enough' state then that is the key process variable to used in a closed loop control algorithm.

Under drying the cloths load is a failure of control objective, over drying of cloths is needless waste of energy and hard on the cloths, I suspect we can agree on that?

Lefty  
Title: Re: Opensource DIY clothes dryer
Post by: Constantin on Sep 06, 2012, 02:50 am
Retrolefty, based on my experience with the DOE test procedure I do not agree with your position. It is not a closed system. So if you can control the flue exit temperature of the drum, you should be able to reduce the amount of energy needed to dry the clothes.  In the beginning of the cycle, you'll be able to run full bore because the clothes are cold and wet. Beyond a certain temperature, the marginal improvement of full heat vs. modulating will become apparent. Whether that justifies the extra expense of a SSR-based PID-enabled control system is a different question.

Similarly, increasing the drying cycle time will likely reduce your need for heat by using "dry" ambient air - for flue-based dryers, the test procedure does not account for the inherent issues in using air from inside the house and then exhausting it. Yet, in real life, that air has to come from somewhere, i.e. it will cause infiltration. Said infiltration is going to impact the home in one way or the other. BTW, there are no 'balanced' flue-based dryers on the market - i.e. all of them source indoor air and exhaust it outdoors.

As for condensing dryers, all of them are based on electric power and are generally less efficient than their non-condensing platforms. The sole exception here being heat pump dryers marketed by Bosch and others in the EU, but not the US (at least, not yet).

I agree with you that measuring dryness of clothes is the best way to ensure good process control, regardless of the control mechanism being used. However, should you find yourself with not enough to do, have a look at the many different ways that people have tried to figure out clothing dryness inside a dryer.

Now a quick suggestion for the OP: Before you rip out the old control system, etc. may I suggest you install all the sensors we talked about and then log the different behaviors of the control system. That gives you a baseline to compare your dryer performance / algorithms to. Just a thought.
Title: Re: Opensource DIY clothes dryer
Post by: boelle on Sep 06, 2012, 08:19 am


most work that way...

but what could improve is variable heat source where most dryers operate on a simple on/off and that will cause some overshoot which is a waste of energy.

Why would overshoot/undershoot be a waste of energy. Is not all the heat energy generated directly going into the drying of the material? As long as you are not continuing to send heat into the material that is already 'dry enough' I don't see where the 'waste' is? Too much heat, time to 'dry enough' shortened, too little heat, time to 'dry enough' takes a little longer, no net change on total heating BTU consumed used to reach the it's 'dry enough' setpoint.

adding an arduino also allows for custom cycles. one of my fav's will be a cycle that targets on humidity but use lower temps, this will of course result in a longer cycle but will save on the bill. Why would this save energy consumed, it should take the same amount of total BTUs to remove xx amount of moisture from the material because it's a heat/time product equation? of course you have to judge time used against heat used... why i included a current sensor so that electricity used can be messured...

again its mostly stitching code together that are my biggest issue in this project.



might just be me, but going over a set temp means waste to me, i agree that i will just get the clothes done more quickly, but i like to go as precise as possible
Title: Re: Opensource DIY clothes dryer
Post by: retrolefty on Sep 06, 2012, 08:37 am
Quote
might just be me, but going over a set temp means waste to me, i agree that i will just get the clothes done more quickly, but i like to go as precise as possible


OK, but the more pertinent question is do you pants care as much as you do?  ;)

If we have a simple thermostat sensor controller that might have a control hysteresis or +/- 5 degrees Vs a P&ID control with a nice RTD sensor that might give a +/- 1 degree variation in control. Where is the wasted energy to be found if your drying by either a simple timed cycle or a 'it's dry enough sensor'? Recall that drying cloths is not a 'fast' process, takes 30-60mins normally depending on load size I would think. Having the process variable temperature varying +/- 5 degree Vs varying +/- 1 degree centered on the same setpoint temperature is not going to change the batch size drying length or energy usage. I don't think on my electric dryer there is any attempt to control the temperature at all, just straight 220 AC to the heating element. There are over-temp safety cut-off switches, but that is for malfunction or major air flow blockage protection. Such simple dryer like that are simple open loop control, with just the user selecting a drying timing they think it will take. A closed loop control based on a 'it's dry enough' sensor would be a more beneficial method and I believe some dryers have that optional control mode?

Lefty
Title: Re: Opensource DIY clothes dryer
Post by: boelle on Sep 06, 2012, 08:38 am

As for condensing dryers, all of them are based on electric power and are generally less efficient than their non-condensing platforms. The sole exception here being heat pump dryers marketed by Bosch and others in the EU, but not the US (at least, not yet).

Now a quick suggestion for the OP: Before you rip out the old control system, etc. may I suggest you install all the sensors we talked about and then log the different behaviors of the control system. That gives you a baseline to compare your dryer performance / algorithms to. Just a thought.


I tend to disagree a bit on condensing dryers, they should be a bit more efficient as they do not just dump the heated air to the outside but recirculate the air inside over the condensing unit and back to the drum. outside air/room air then passes over the condensing unit on the other side and cools it down hence the water in the air on the drum side will start to drip off in a container for my machine, others just let the water run out via a small pipe. i have attached a pic of the condensing unit itself, easy to take out as you need to rinse it once a month or every 3 months, i just take mine with me in a shower.

but yeah placing the sensors before ripping the control was also my plan, at least i can mimic the cycles allready there and then change them to the better.
Title: Re: Opensource DIY clothes dryer
Post by: boelle on Sep 06, 2012, 08:50 am

Quote
might just be me, but going over a set temp means waste to me, i agree that i will just get the clothes done more quickly, but i like to go as precise as possible


OK, but the more pertinent question is do you pants care as much as you do?  ;)

A closed loop control based on a 'it's dry enough' sensor would be a more beneficial method and I believe some dryers have that optional control mode?

Lefty


I think for a short cycle with high heat it would not matter much, but my goal is to lower the temp and run a bit longer since rotating the drum is not the most expensive part.
Also a pid control is not that expensive, all it takes is a zero cross detection chip and a triac... i have most the idea from this page: http://www.over-engineered.com/projects/sous-vide-pid-controller/
I found a board with all the bits here: http://www.inmojo.com/store/inmojo-market/item/digital-ac-dimmer-module/

My dryer is a closed loop or i would say must be since it does not blow the heated air to the outside, so there must be some way it can detect when the air is dry enough... again i think there could be a bit saved by lower temps and longer cycle...
Title: Re: Opensource DIY clothes dryer
Post by: boelle on Sep 06, 2012, 08:52 am
forgot to say that on my condensing unit the room air is blown from the back side towards the handle and the hot air from the drum passes over the fins and goes back to the drum.
Title: Re: Opensource DIY clothes dryer
Post by: retrolefty on Sep 06, 2012, 08:59 am


Quote
might just be me, but going over a set temp means waste to me, i agree that i will just get the clothes done more quickly, but i like to go as precise as possible


OK, but the more pertinent question is do you pants care as much as you do?  ;)

A closed loop control based on a 'it's dry enough' sensor would be a more beneficial method and I believe some dryers have that optional control mode?

Lefty


I think for a short cycle with high heat it would not matter much, but my goal is to lower the temp and run a bit longer since rotating the drum is not the most expensive part.
Also a pid control is not that expensive, all it takes is a zero cross detection chip and a triac... i have most the idea from this page: http://www.over-engineered.com/projects/sous-vide-pid-controller/
I found a board with all the bits here: http://www.inmojo.com/store/inmojo-market/item/digital-ac-dimmer-module/

My dryer is a closed loop or i would say must be since it does not blow the heated air to the outside, so there must be some way it can detect when the air is dry enough... [font=Verdana]again i think there could be a bit saved by lower temps and longer cycle..[/font].[/b]


Yes and others have stated that opinion also, but I'm still skeptical of that. I'm of the opinion that it takes a certain total BTU consumption to dry a given load of laundry, and you will pay for the same total amount energy, regardless if you run twice as long at half the temperature vs half the time at twice the temp. There must be some fundamental law of thermodynamics that can prove or disprove that. Plus the constant tumbler motor energy consumption kind of adds a bias against using longer runs. Just because some energy saving idea may seem intuitively better, does not in fact mean it is. It should first be able to be proven mathematically, no?  
Title: Re: Opensource DIY clothes dryer
Post by: boelle on Sep 06, 2012, 09:27 am
i just took the idea from the crock pot link and also from my dishwasher, the 45 degree cycle takes 2 hours 55 mins and the 70 degree takes 2 hours and 15 mins. i can reduce the time on the 2 by pushing a button called "vario speed" then the times are 1:30 and 1:27, the difference is water used and the speed on the pump the circulate the water. it do cost more since more water used and you need to heat more water.

of course that can not be used as a direct compare but there is a bit of it, lower temp but run longer, 40 mins in difference but the amount of water is the same... so we lower the temp but run 40 mins longer to get the dishes clean. of course there is a point where the math does not add up any more, ie where the longer run is not justified against electricity used to keep the water at 45 degrees.

of course it raise the need for a google search on how to figure the break even point
Title: Re: Opensource DIY clothes dryer
Post by: Constantin on Sep 06, 2012, 01:39 pm
The mathematics are quite simple.

1) For a non-condensing dryer (i.e. one with a flue pipe)
The hotter the exhaust gas, the more you're heating the exterior vs. heating the clothes.

2) For a condensing dryer
The hotter the exhaust gas, the more you have to cool the flue gases before you can extract the latent heat.

Either dryer uses ambient air to its advantage - the condensing type may recirculate air internally but it is also running external air over the condenser HX continuously - otherwise it wouldn't condense. The non-condensing dryer derives a benefit from more ambient dry air being pumped through the machine and hence absorbing some of the moisture at the very low cost of drum rotation and blower use. In either application, the heat is the primary 'cost' of operation. So to the extent that you can maximize the heat being absorbed by the clothes vs. blowing it out to atmosphere (or into the house) you will benefit.
Title: Re: Opensource DIY clothes dryer
Post by: boelle on Sep 06, 2012, 02:34 pm
hmm... so if both drum and both airflows are driven by the same motor there is not much point in doing anything advanced...

but if i could adjust both airflows individualy there would be some benefit... ie let the internal flow be slow and the external high so that the internal is  cooled as much as possible hence is would condense more..

am i total off?
Title: Re: Opensource DIY clothes dryer
Post by: boelle on Sep 06, 2012, 10:24 pm
just been fooling arround with my simple "setup" sketch so now i can update wifi config...

have tried to figure how i could add a single cycle so that i could start it remotely, later i would add local start of the cycle...

a guy made a dishwasher controlled by arduino and its very logic to me how it runs, but how could i do it over wifi?

http://pastebin.com/0Zec1xLc (http://pastebin.com/0Zec1xLc)

i can redo the main page no problem with that.. what i would like is at the main page i click a cycle... it should then draw a page that says what cycle its running and sensor values and target vaules... temp reading could be done with a one wire dallas chip and heat control could simply be on/off for now. for moisture sensing i found this http://www.digikey.com/product-detail/en/CHS-GSS/445-2575-ND/931221?cur=USD (http://www.digikey.com/product-detail/en/CHS-GSS/445-2575-ND/931221?cur=USD) it puts out 10 mv per % so 100% is 1V and it can be driven from 5V supply

so what i need is pointers on how to make a cycle... i have a mega so there should be enough pins. for now lets just say 1 pin for drum rotation and airflow. another pin for heat control. and 1 pin for moisture sensor and another pin for the dallas chip.

my dryer do reverse the drum direction every now and then for about 5 secs. i guess its to keep the clothes from going in to one big ball.. would like to keep that and guess it requires another pin

my code is taken from here, i have only added "back" links to each page


http://notebook.kulchenko.com/embedded/storing-wifi-configuration-in-eeprom-on-arduino (http://notebook.kulchenko.com/embedded/storing-wifi-configuration-in-eeprom-on-arduino)
Title: Re: Opensource DIY clothes dryer
Post by: boelle on Sep 20, 2012, 02:47 pm
nobody able to help me stitching the code together?
Title: Re: Opensource DIY clothes dryer
Post by: boelle on Sep 23, 2012, 12:21 am
so i tried to add 2 one wire temp probes... only trouble is figureing out how to display them and in the end make a simple cycle out of it....

i would like to have a /cycle1 page and display the 2 dallas chip temps and maybe one of the analog pins and keep it in that loop until the analog pin has a set value... i was thinking of a while statement so that i could step through the cycle...

ie first step is to heat up and keep temp with simple on/off (might make it more advanced later on)
after temp is reached step forward and target humidity while keeping the temp
next step is to shut off heat and only turn the drum once in a while (cooldown)

after cooldown return to the mainpage...

add on top that if one user starts a cycle and others wants to look in they should be directed to the cycle1 part as long its active

my sketch so far: http://pastebin.com/m1DJDjcL
Title: Re: Opensource DIY clothes dryer
Post by: boelle on Sep 23, 2012, 12:51 am
the define section now look like this:

#define LEDPIN 13 // LED simulating heating element
#define LEDPIN 14 // LED simulating motor turning drum
#define LEDPIN 15 // LED simulating indicating drum turning reverse (used to distribute clothes)

#define ONE_WIRE_BUS 16 // Data wire from dallas chips
#define humidpin 17 // humidity sensor
#define waterpin 18 // watertank full
#define currentpin 19 // analog voltage input from current clamp
#define airflowpin 20 // analog voltage from airflow sensor

and part where i set if pin is output/input has changed to:

pinMode(13, OUTPUT); // heating element
pinMode(14, OUTPUT); // drum motor
pinMode(15, OUTPUT); // drum reverse

pinMode(16, INPUT); // DS18B20 one wire bus
pinMode(17, INPUT); // humidity sensor
pinMode(18, INPUT); // watertank full
pinMode(19, INPUT); // current clamp
pinMode(20, INPUT); // airflow
Title: Re: Opensource DIY clothes dryer
Post by: boelle on Sep 26, 2012, 03:26 pm
damm  XD

even a simple thing as jumping from one loop to another is causing trouble... ie if i write /cycle1 after the ip the code should take it to another loop i also call cycle1

the idea is to create a loop that simply displays what cycle is running and status... it should then refresh every x sec's and when done it will/should return it to the main loop

http://pastebin.com/3dT8M6AZ

on line 194 i try to jump to the cycle1 loop (line 283)...

but nothing happens... other than that the code works

some able to help me?
Title: Re: Opensource DIY clothes dryer
Post by: boelle on Sep 27, 2012, 12:43 am
made a menu and place where target values can be entered... settings form just there still need to figure how to store settings... in danish thou but you should be able to understand or else just ask:

http://pastebin.com/Wwut1iJD
Title: Re: Opensource DIY clothes dryer
Post by: boelle on Oct 17, 2012, 02:36 pm
anybody that can give a hint on how to store a table cell in eeprom?

reading is easy enough, just do do eprom read in to a variable and then set the cell value to that or am i mistaken?

then change whatever cells needed and hit save....

been look at this on/off for weeks but not sure, many examples use for next loop etc and i cant figure it

EDIT: my table starts at line 410 in the above paste bin, what i would like is a SIMPLE example on how to store the cell c1temp