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Powering the MiniE and stepper motor
#1
Hello,
I am trying to get the hardware end of the miniE V.1 operational, but I've ran into a snag...
I'm not entirely sure how to power the easy driver/stepper motor. I'm using a 12V 1.25A DC power supply. If I plug it into the arduino DC jack should it power the entire project or just the arduino? Right now it just powers the ardunio with now movement from the stepper motor.
I'll include some photos
This is my first attempt at a real electronics project so if anybody see errors please let me know Smile

Thanks!


[Image: photo%20(1).JPG]

[Image: photo%20(2).JPG]

[Image: photo.JPG]
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#2
Wow...huge pictures!

Well, Ardino CAN power the stepper motor all right but I'm not sure this is the best ideea.
Steppers eat much more that Arduino's regulator can provide and it has nothing to do with how bit your Arduino power supply is.

Currently pin M+ from EasyDriver is hooked to the Vin of Arduino and this is the reason why your stepper motor can be operated.
Otherwise, as mentioned in the EasyDriver documentation, it can handle voltages from 7 to 30V or so...
That is, two power supplies: one for Arduino and the "brain" stuff and another power supply for the "muscle" (separatelly connected to M+ of the driver).

But, I'm affraid there's some more to study on that.
If you have the time...you might even like it :-)


https://www.sparkfun.com/tutorials/400

https://www.sparkfun.com/products/10267
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#3
(04-12-2013, 11:09 PM)keith.h Wrote: Hello,
I am trying to get the hardware end of the miniE V.1 operational, but I've ran into a snag...

Hello,

the pictures show no obvious errors - as long as you followed the original "stacking architecture" of the different boards. There are some things I would test in the forst place in your situation:

  1. Is the power supply working at all?
  2. Are the power rails (+5, Vin) shorted with Ground (you need to have a multimeter to test this)?
  3. Is the whole system staying dead when power is connected or is it partially working?

Airic
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#4
Thanks for the explanation alexella! that makes sense.
And thank you for your reply Airic!

I narrowed it down to the easydriver it was either DOA or I somehow fried it....Everything powers up and runs except for the motor.

What would be a good basic list of settings (Motor steps, max steps, motor sleep, etc) to just send input to the easydriver and ensure that its not a software thing. I'd hate to keep buying hardware and find out that I'm stupid and don't know how to run the software.

Thanks for the help guys!
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#5
(04-25-2013, 07:13 AM)keith.h Wrote: What would be a good basic list of settings (Motor steps, max steps, motor sleep, etc) to just send input to the easydriver and ensure that its not a software thing.

Hej,

do you have any possibilities to check some voltages on the EasyDriver when it is powered (do you have a multimeter)? You could verify that it is powered correctly and there is no cold solder joint / a solder bridge or something else wrong with the connection to the shield. Is the power-LED of the EasyDriver on when it is powered?

If you did not change any settings in the software, the default ones should work pretty well. You can reset the settings by changing the version or the subversion number in the code (you'll find that in the main file on the very top) to something random and then flash the software again. All you need to make sure after this is that you have some motor steps defined because this is what the motor will do finally (but I think the default value is 800 which is half a turn of a standard stepper).

Good luck!
Airic
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#6
I'll barge in also with a power related question.

SHORT STORY:
- what about external power supply for EasyDriver?
- do I have to insert some Diodes to protect the two circuits (Arduino and EasyDriver)? I guess I have to take a look at the internal Arduino schematic


LONG STORY:
I'm still uncertain of my final portable solution and I'm trying several powering solutions.



OptionA: Arduino (+motor) and Camera powered from 7.4V LiPo

Pro:
- I've got a lot of 2S LiPo's laying around, waiting to be usefull
- the voltage regulator for the (CHDK enabled) camera runs cool (-er)
- Arduino is happy enough with 7.4V, it's own regulator is cool and happy

Cons:
- not enough power for my Motor (Mercury SM-42BYG011-25 ). Not enough and the whole thing is skipping steps like helll


OptionB: Arduino (+motor) and Camera powered from 11.1V LiPo

Pro:
- stepper motor works like a charm
- everything else works fine

Cons:
- CHDK (enabled) camera voltage regulator is...65C hot. I expect that in the sun it could reach 100C
- Arduino voltage regulator also... a little hot. If the enclosure is airtight, I wonder if the whole thing won't heat up to much.


OptionC: 11.1V Battery + DC-DC converter.

This will solve the heating problem for the CHDK camera but for Arduino.... Well, he might survive :-)
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#7
(04-28-2013, 06:00 PM)alexella Wrote: OptionA: Arduino (+motor) and Camera powered from 7.4V LiPo

..no option because it is not working.

(04-28-2013, 06:00 PM)alexella Wrote: OptionB: Arduino (+motor) and Camera powered from 11.1V LiPo

This is my configuration and I never had any problems. Depending on your DC-DC converter, the max temperature these things are designed for is 150°C. I guess the heat-up of the stepper-driver-IC is a bigger concern and producing much more heat. And finally, 12V is totally fine for the Arduino UNO.

(04-28-2013, 06:00 PM)alexella Wrote: OptionC: 11.1V Battery + DC-DC converter.

Well, this would just bring down the temp of the Arduino's DC-converter which should have no problem with 12V.

Airic
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#8
I agree: 3S packs (11.4V approx) is the optimal power supply.
It's enough for motor, for Arduino, and (in my case) it's enough for the 4cells cameras that require approx 6V to work.

It's just a pitty that most of my packs are 2S :-(
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#9
Just a note. If your motor operates at a voltage between 6 and 20 V, then you do not need a second power supply.

Arduino UNo can be fed directly with voltages between 6 and 20 V, (http://arduino.cc/en/Main/ArduinoBoardUno) and the miniE board connects directly the power pin (Vin) (and a big amount current can be drawn through this pin) with M+ of stepper driver.

This means that if the operating voltage of your motor is between 6 and 20 V, then you can feed all the system (including motor) directly through the main Arduino power connector.

Back to main question... Your motor doesn't run. Did you notice that Motor steps defaults settings are = 0? Big Grin

Greetings,
Anderl
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#10
Well, now that you've mentioned, I've got a couple of concerns regarding the Stepper external powering method.


I've noticed in the original schematic that Arduino's Vin is connected to the M+ of the EasyDriver. This setup allowes EasyDriver to receive allmost all the voltage that is supplied to the Arduino socket while Arduino is using it's own internal voltage regulator to get it's required 5V.
I would suggest caution in connecting two separate power supplies to the Arduino.
(Vin in reverse => Arduino kaput
Vin > Arduino DC input ==> ??? might not be ok)

Electrical suggestion1: use the EasyDriver ONLY from an external power supply by removing the PCB connection from EasyDriver M+ to Arduino Vin

Electrical suggestion2: put some diodes that will allow EasyDriver to be powered either by Vin or by and external (bigger) voltage connected to "MotorRaw" connector on PCB.

I hope I'm not making any high school mistakes here :-)
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