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1  Using Arduino / General Electronics / Re: Staying organized? on: February 12, 2012, 02:57:41 pm
Hi Peter

I have tried numerous systems, but at the end of the day they usually taking up too much space for the volume of components to be stored.

Right now I am trying Craft Mates Lockables
ttp://www.createforless.com/search/results.aspx?txtSearch=Craft%20Mates%20Organizer&gclid=CPmAkvWSma4CFckZQgoduA5BIQ
The pictures online does not do them justice

I purchase mine from Michaels, they are in the bead section.  Price is very reasonable.

2 basic box sizes 2xL and 3xL in strips of 1x7 or 2x7 containers
They are clear, so easy to determine what is inside of a box
They locking mechanism is interesting, I am still getting use to them.  Very tight at start, you need to get one lid open, then the others are easier with one open. 

Fully sealed, so no risk of components migrating between containers (they were meant to hold small beads).

The box sizes are just right to usually hold about 25 small pieces (LEDs, Transistors, etc).  Sadly, the 3xL will not hold resistors without cutting down the lead length.

I keep similar components e.g, transistors in one strip.  Makes it easier when getting components.

Resistors are stored in the 2x7 cases, all the n x1K in one strip, all the n x10k in another, etc.

Hope this helps.

Regards  Bill



2  Using Arduino / Motors, Mechanics, and Power / Re: Need more stable power on: September 06, 2011, 01:34:35 pm
Hi GregN

Is replacing the batteries with a power supply an option, or does the camera need to be mobile?

Regards  Bill
3  Using Arduino / General Electronics / Re: Latching power schematic - am I doing it right? on: August 29, 2011, 08:51:01 pm
Hi Howieem

I was looking for something else when I came across this SPec sheet.

There is a remote shut down circuit in the notes

http://www.makershed.com/v/vspfiles/assets/images/l7805.pdf

Regards  Bill
4  Using Arduino / General Electronics / Re: tip 120 controlling relay. resistance help on: August 29, 2011, 12:31:46 pm
Hi Roybenmo

Check ou this tutorial, good explanation when using transistors as a switch with calculations.
http://www.electronics-tutorials.ws/transistor/tran_4.html

Rgerads  Bill
5  Using Arduino / Motors, Mechanics, and Power / Re: Velocity Profile in a DC motor on: August 26, 2011, 03:07:52 pm
3rd degree velocity profile

Hi teddybear

This site may help about smoothstep
http://sol.gfxile.net/interpolation/index.html#c5

It mentions 3rd power, which maybe what you are looking for?

Regards  Bill

6  Using Arduino / Motors, Mechanics, and Power / Re: changing a polarity or a +/- of a dc motor? on: August 25, 2011, 10:27:01 am
Hi Muneeb

Simplest solution DPDT switch (double pole double throw)

If you used center off, then you would also get an off position.  The motor gets wired to the center position.

E.g.  http://www.robotroom.com/DPDT-Bidirectional-Motor-Switch.html

Regards  Bill
7  Using Arduino / General Electronics / Re: Resistors on: August 25, 2011, 09:59:38 am
Hi Lo5545

Absolutely no difference in operation.

If you were to measure the voltage from the mid point of either circuit (between resistor and lamp) to the -ve supply terminal, then you would see a difference, unless the lamp resistance was equal to the resistor.

Rgeards  Bill
8  Using Arduino / General Electronics / Re: Practical experience operating Consumer ICs outdoors on: August 19, 2011, 10:17:50 am
The ATMega328P is rated over a pretty broad range. How cold are you likely to see?

Temperature Range:
 -40°C to 85°C

-40C = -40F, that's pretty cold!

Hi Crossroads

-30C for several days or more is not uncommon in the Calgary area.  Thats base temperature, wind chill can take it considerably lower.  Like to be believe it is a dry cold so not as chilling as a damp Toronto or Boston cold.

I am orignally from Toronto, and have visited Boston often for work and my hobby.  Too bad about Edaville a two foot railroad park, about an hour south of Boston did not survive.   People would know the area as Ocean Spray, the cranberry people.

The good news, is for my project, when it is getting that cold, I will be firing up the electronics to keep the 120V pond heater running at 100%, so I will be receiving some secondary heat from the heater circuitry to keep the enclosure warm.

Regards  Bill
9  Using Arduino / General Electronics / Re: monitoring 120/240 vac on: August 17, 2011, 11:02:17 pm
n.

I am looking to monitor a generators output 120/208v  &  120/240v


Hi 02660

Have you considered also monitoring the current.  Not my area of expertise but I suspect there would be large switches inline to switch from mains to generator.  Monitoring current would ensure you are seeing a load on the generator.

Regards   Bill
10  Using Arduino / General Electronics / Re: Practical experience operating Consumer ICs outdoors on: August 17, 2011, 10:54:21 pm
Thanks for the replies so far:

Lefty  - for the resistor suggestion

Bobnova – solar panel(s) are self draining (pumping the pond water through it so antifreeze not an option if I want the fish to survive), and water pump will be turned off before internal panel temperature reaches freezing.

Drmn4ea – your experiences are illuminating, and I had not considered condensation.  The fact I am considering future wireless control, from your experience keeping the module warm will be a consideration.

Techone  - I know the pink stuff very well, used many sheets on my train layout for scenery the new purple has better R factor,  as for rain, Calgary is almost a desert re: rainfall, and the snow is dry ;^)  

11  Using Arduino / General Electronics / Re: Practical experience operating Consumer ICs outdoors on: August 17, 2011, 05:35:27 pm
Quote
If I go with heater, what have you used for a heater?

Just use power resistors sized for the amount of heat required. Turn them on and off via a switching transistor wire to the arduino with a temp sensor. Or pwm it with a PID control function and have continuous heater control. Resistors are 100% efficient at converting electrical power to heat output.  smiley-wink

Good sugestion, available power power is not limited, as I have ruled out using batteries, too cold and power requirements to be met,  the pump  will require 12V 2A and heater 120Vac.

I also considered good old fashioned light bulbs, that generate heat.  They say to heat a doghouse in Calgary with a incadescent 100W light bulb, to keep the dog warm, not sure how low of a temperature that would be effective. 

Regards  Bill
12  Using Arduino / General Electronics / Practical experience operating Consumer ICs outdoors on: August 17, 2011, 04:51:23 pm
I am in the initial stages of investigating an outdoor project that would expose the electronic components to less than -30˚C during winter operation.  During the summer it would be disconnected, so the high end temperature is not a concern.   

Project is to build a solar pond heater to keep the fish pond from freezing over during the winter (it is a shallow pond and deepening is not really an option for the size of my pond).  If it works this winter then I will add additional features for auto-logging performance remotely with an Arduino (and wireless) to provide more granular control.

First step in my project is to monitor: air, solar panel and water temperatures.  Based on conditions, simple logic will determine whether to pump water to the solar panel, or assist with a heater, or night time heating required.   

Was planning to use Consumer Grade electronics due to easy availability which generically only should operate as low as 0˚C. 


Question to the group is: “What is your practical experience when placing electronic projects outdoors in cold temperatures?”  I have never built anything to operate outdoors during the winter.

My thoughts so far:

1) Just source Military grade components and forget about it?

2)  Space is not a concern , I can build a larger enclosure with insulation to retain any heat generated by the electronics which should not be much (op amp, comparator, and some 74xxs, power transistor), the pump motor will only be driven electronically during daylight hours, so I cannot plan on constant heat from the transistor..

3) Adding another LM335 transducer to monitor internal temperature of enclosure to start a heater if required.   Considering the energy required to heat the enclosure, the purchase of higher grade components becomes justified for the test period.  However, for adding something like the Xbee transmitter, planning for heating up front maybe beneficial long term.

4) If I go with heater, what have you used for a heater?

Thanks for your suggestions or experiences.
13  Using Arduino / General Electronics / Re: Possible solutions for reducing current load on: August 16, 2011, 02:23:22 pm
Hi Existence

Aoother possible solution is looking at the 74HC05 Inverter with open drain outputs.

Each output is capable of 20ma

One IC has 6 drivers, and would take up less space then the equivalent transistor with base resistor. 

Regards  Bill
14  Using Arduino / Motors, Mechanics, and Power / Re: relay h-bridge / flyback diodes on: August 16, 2011, 09:26:22 am
The voltage spike is in the forward direction of the diode not the reverse direction. Even if it were in the reverse direction the whole point of the diode is that you want it to break down and short out the spike.



Hi Mike

H Bridge, while stopping, two diodes are conducting the spike in the forward direction, two diodes are reversed biased.

Regards  Bill
15  Using Arduino / Motors, Mechanics, and Power / Re: Motor controller on: August 16, 2011, 09:21:23 am
Hi darkimchi

Motor locked up or stalled is when the motor is prevented from turning.  e.g. you apply full power and grab one of the wheels and prevent it from turning.

A poorly designed gear set could jam.  You could drive into something and your wheels do not slip, so the motor tries to keep running.

Regards  Bill
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