Hi, I am in need of having something, probably an arduino turn on and off two stepper motors.
It needs to turn one stepper motor's shaft 90 degrees or 50 steps every fifteen seconds.
The other stepper motor is in a peristaltic pump and it needs to run for fifteen seconds, and stop for whatever time it takes for the first stepper motor to turn 90 degrees.
And it just needs to repeat that, over and over and over again.
I have absolutely no idea how to go about this, what parts to buy, or how to code. So I'd love any help at all. Once understanding what parts I need, understand the theory behind it and have the items in hand, I'd probably be happy to pay someone for the code.
Thanks!
if you have an UNO and some LED's you can get some experience in your needs.
for your application, I would fully expect that a stepper driver will have two inputs that you must use and a couple that you may or may not use.
step and direction.
you send a pulse out on the step and the motor takes a step.
you send a value out on direction and the motor spins one way, remove that value and the motor spins the other way.
often there will be an enable pin that is optional. usually pre-set to enable.
WIRING is the most important part. get that right and things work well, get it wrong and things burn up.
you set the blink to be as fast as you need for your motor to spin at the speed you want.
you set a timer to run for 'x' seconds.
once that timer times out, the other motor runs for the 90 degree rotation then stops
then the first motor runs for the 15 seconds.
this is beginner programming, so you should be able to make it work straight away.
set up two LED's on a breadboard and get one to blink for 15 seconds, and stop
then the other to blink 50 times really fast, and stop.
then the first to blink again.
Awesome thank you guys - that really alleviated a lot of concern.
Would it be okay if I posted a link to all the motors and items I am intending on purchasing for this for further discussion?
I am working on making an open source automated petri dish filler. It will have 4 petri dish holders on a base plate that rotate. the base plates will be 4 - one for the entire petri dish to fall into, another to catch the lid, but allow the bottom to fall, and the other to catch the bottom and pull it along as it rotates. Imagine an extremely simple and smaller version of this: - YouTube
So the goal is to have a peristaltic pump on a stepper motor fill the dishes with 15ml of liquid agar. I plan on using this: http://www.ebay.com/itm/171813908923 This was chosen because the tube needs to be easily moved for sterility purposes. It does 120ml per minute, so potentially 8 petri dishes per minute.
But - it sounds like I just need to know the motors I am using; which is two 42 stepper motors, and I am unsure what the motor is for the linear actuator.
Thanks! Not sure what else guidance you can offer me.
Actually I guess my real issues are figuring out how to setup the drivers, power supplies, and all of that. Electronics and programing s really not within my skill set. More of a chemistry/biology type.
Thanks! I'll look into the driver and the Nano.
What seems tiny about that motor? I haven't seen larger stepper motors, but also it only needs to spin 3 metal plates which are probably 1mm galvanized steel plates, ~250mm in diameter, but with 4 ~100mm circles cut out from them, plus 3 petri dishes. They've yet to be made, but I am approximating the weight to be about 600 grams, and will be supported on a ball bearing plate; so having the motor turn it I don't think will be a problem (though, is there a bigger motor than the 42 stepper motor you'd think would be better for this task?)
As for that stepper motor driver, do I need one for each stepper motor? or does that one work for both?
I'll look into it more, probably works for both, just haven't had time yet.
The linear actuator might be a more problematic issue. As a driver might not be available. If there isn't a driver available, what does one do? what options exist?
Maybe a driver isn't even needed for it, and it's just a timer mechanism since I guess it's speeds don't change really - it just either goes up or down.
The motor you linked to in Reply #6 seems very normal (not tiny) to me. It should work well with a Pololu DRV8825 stepper driver. The Pololu web page has good instructions. You can test with this simple stepper code.
Rather than try to design and choose everything before you get started I suggest you "learn" your way through the project piece by piece. Get the motor and driver board and an Arduino and a motor power supply and experiment with programs to make the motor do what you want.
Robin2:
The motor you linked to in Reply #6 seems very normal (not tiny) to me.
motor on the pump. spec from e-bay:
Peristaltic pump technology indicators:
Speed range:1 to 50.0 rpm reversible
Velocity resolution:1rpm external control: 0.1rpm
Power consumption:less than 10W
Working environment:Temperature 0 to 40 degree,relative humidity less than 80 pecentage
Stepper motor:42 stepper motor
Pump head Weight:80g
Motor weight:400g
Protection class:IP31
power is 10 watts.
the chineese data shows 0.9 amps
the actual stepper motor :
Rated Current/Winding: up to 1.4A
Supply Voltage: up to 36VDC
I would offer that perception is in the eye of the beholder.
I would want to see the nameplate of the stepper on that pump.
for rotating the stage, the NEMA17 is serviceable, although is is listed as 10 volts, pretty high.
ebay 331434566033 is listed at 2.2 volts so it will perform much better. although in this application, both should work.
Robin2:
It should work well with a Pololu DRV8825 stepper driver.
...R
using my crystal ball, the poster is not a hobbyiest and would rather buy a device that costs about the same, but does not require additional soldering.
so far the parts you have chosen seem to be in-line with your project. the linear actuator is slow, but could work. you can put that on a lever to increase distance of the movement as it is so powerful.
each motor requires a separate driver. one motor, one driver.
dave-in-nj:
using my crystal ball, the poster is not a hobbyiest and would rather buy a device that costs about the same, but does not require additional soldering.
Do they sell such small levers that would work? I agree, that linear actuator is very slow and is currently the bottle neck for petri dishes per hour. A lever is a great idea, and I tried to come up with something like that or originally using a servo motor, but couldn't really find anything that seemed simple and effective.
Cool, thanks! I'll add another driver to the list.
Also I am having a hard time understanding the benefits from this stepper motor for turning the plates, and the other stepper motor:
On eBay 331434566033 vs 111013104964 one seems weaker but uses less volts and more amps?
This is the power supply I think I'd be using as it is 12 volts and 2 amps: 191210306026
That seems to work for all items I currently have (I think?) assuming that the drivers or items adjust, use or pull the amount of volts and amps they need - or are within the 12v/2A range.
Also this is my first arduino project or even mechanical/electrical project ever - My intentions aren't necessarily to get involved with this hobby but just to have a nice properly functional automated petri dish pouring machine that does a sleeve of 25 or more at a time to save me time and effort in the lab while making more consistently filled petri dishes. Based on my approximations this one ought to be able to do 400 petri dishes and cost around $300 when finished. The cheapest commercial ones are $20,500 it seems and only do 800 petri dishes per hour. I'm intending to have the model open source for others to build their own as well without any expertise (buy these items, connect them together, add this code, etc) assuming I get it working and everything.
But anyway; my understanding of all of this is very little, so hopefully I am not too much of a pain! Thanks a lot guys. You've all been very helpful.
Dave-in-nj is correct, if soldering can be avoided, that is preferable. I think he was suggesting this driver as it doesn't require soldering: 331555572152 but perhaps I am mistaken?
Will that driver not work for both stepper motors? the one on the peristaltic pump and the one that spins the plates?
Also all the data sheets and info on these items I have are on ebay; not sure where else they'd be.
Vesp:
Also I am having a hard time understanding the benefits from this stepper motor for turning the plates, and the other stepper motor:
On eBay 331434566033 vs 111013104964 one seems weaker but uses less volts and more amps?
Edit 15 JuneThe voltage figure is largely irrelevant. Stepper motors are usually driven at a voltage considerably higher than the nominal voltage. The amps figure is important for getting a suitable stepper motor driver and the torque is what is important for figuring if it can do the job. In general, the motors that use more amps for a given torque will probably be capable of working at higher speed. But I don't think you need high speeds.
My intentions aren't necessarily to get involved with this hobby but just to have a nice properly functional automated petri dish pouring machine that does a sleeve of 25 or more at a time to save me time and effort in the lab while making more consistently filled petri dishes.
What you are taking on is not a trivial exercise - like building flat-pack furniture. If you don't already have a background in programming and mechanics you are facing a very steep learning curve - especially when it comes to figuring out the inevitable bugs in your code. Someone with a hobby interest won't mind putting in a lot of learning and experimenting time.
No matter what your level of general experience the normal way to deal with new parts is to write separate short programs to learn how to use them and only try to join the bits together when you have mastered them all separately.
Almost certainly you will find the need for something that you have not thought of at this stage.
Also all the data sheets and info on these items I have are on ebay; not sure where else they'd be.
A link to the Ebay page is better than nothing but you should try to find the manufacturers datasheets and post links to them. When you refer to Ebay stuff (or anything else on the internet) please always provide complete links.
