Hi,
I have the stepper motor Control Board 36820 MS as described here:

and I'm trying to turn the stepper motor 1/3 of a revolution with every press of a button.
I'm working with 6v but do not have enough room in my model for limit switches. Can this be done and is this the right board or is there a different one that will achieve my requirements.
Thank you in advance for any help.
Regards,
Peter.

 

This is my current test setup and the indicator pin moves just 1/3 back and forwards at the moment

 

This is my current test setup and the indicator pin moves just 1/3 back and forwards at the moment

Have you selected the correct jumpers on the board?
From the data sheet - https://www.mpja.com/Multifunctional-Stepper-Motor-Driver-Control-Board/productinfo/36820 MS/
4 operational Modes: Jumper Select ....
Auto: (Back & Forth) One Button Start and Stop, Other button Forward and Reverse, Potentiometer for speed, Second Potentiometer for automatic round-trip steps. After starting, the motor will automatically run back and forth within the steps adjusted by the pot.

 

Hi,
Yes, I’ve tried various jumper positions and the start/stop sadly cannot be set to a distance which is what I need.
thank you for replying.
At the moment I think I’ll need to find a different controller but it needs to be small. Peter.

 

I think the solution might be to use a 555 timer circuit with a precise on time for every push of the button. Does anyone have such a circuit?
Peter.

 

I'm going to try this circuit unless anyone disagrees or has a better one.
https://elonics.org/adjustable-auto-on-off-delay-timer-circuit-using-555/

 

Sounds like you want to drive the stepper motor an exact number of steps rather than a fixed amount of time. I'd recommend driving the motor with a SN754410 H bridge driver controlled by an Arduino. The processor could be a Seeeduino XIAO to be compact and they are not expensive. You can buy breakout boards with a stepper driver but the SN754410 is really simple - check out the datasheet.

You don't say which stepper motor you are using. If it's 200 steps per revolution you will not get exactly one third of a revolution - you can program code to do 67 steps on the first press, 67 on the second and just 66 on the third press to get a complete revolution in three steps.

I urge you to try using a processor like this - it's not a huge learning curve and once you are familiar with the Arduino IDE you'll think of so many things you can do with it! Once you've downloaded the Arduino IDE you can download stepper motor libraries, or write your own code if you understand how a stepper motor works. If you give it a go and need help you can find it here...

 

Thank you Jerry,
Yes, I had already worked on needing that combination of steps for my 2 phase 4 wire micro motor. I will read and learn about the SN754410 as it sounds exactly what I need. Thank you again for very helpful information.
Peter

 

You are most welcome Peter

https://itp.nyu.edu/physcomp/labs/m...controlling-a-stepper-motor-with-an-h-bridge/
might be helpful

 

Hi Jerry,
I’ve followed your links and can see that this is definitely the way to go to get my project to work.
Arduino is a whole new world to me which I am now very keen to learn. Before my retirement I was an Excel VBA programmer so hopefully this IDE should make some sense.
if I may I’ll let you know my progress.
Thank you for your help.
Peter

 

Hi Jerry,
I have downloaded the Arduino IDE program and very interested to continue. Am I right in thinking I can buy the UNO R3 ARDUINO Compatible Board ATmega328P-U with/without USB Data Cable from eBay and connect it with the SN754410 as shown here: https://www.hobbytronics.co.uk/stepper-motor-sn754410. And then re-write the code to my required steps will get me working. If that’s right I will be very pleased to go ahead.
Thank you
Peter

 

BTW: my project requires two stepper motors to move exactly the same together, I take it the current required won’t be a problem.
Peter

 

After double checking the above won’t fit so I’m thinking of going with the Seeeduino XIAO SAMD21 M0+ Microcontroller Arduino System Seeduino Type-C UK from eBay which is very compact
Peter

 

Hi Jerry,
After thinking about how an Arduino System works and the 67,67,66 stepping setup I can see a flaw. If a user after switching on only pressed once or twice and then switched off, the next time it would start at 67 again and therefore be one step out. This could happen multiple times and the whole 1/3 requirement is lost. On top of that I’m struggling for space and two boards isn’t possible. So I’m back to my original setup and the user will just hold down the button to the desired position with each press.
Than you for your time and comments.
Peter

 

Hi Peter,

That's a problem with stepper motors in general - you don't know where they are! The beauty of a processor is that you could arrange for the number of steps to be 67 but have a small magnet pass a hall sensor in the middle of one of the three movement cycles checked between each step, if the hall state changes the steps could be reduced to 66 for that cycle.

I'm surprised that you are saying the 36820 MS control board is more compact than the Seeeduino XIAO mounted on a small piece of strip board with one 16 pin IC - did you check the the dimensions? The Hobbytronics link you posted shows how simple the connections are. It'll work with V1 (pin 16) connected to the 3.3V XIAO pin and the motor supply voltage V2 (pin 8) can be higher. I believe the SN754410NE can drive up to 1.5A whilst the 36820 MS is limited to 800mA. Depending on the current your motors need, two motors run in parallel should be okay. If the loads on the motors are small it's actually possible to run them with resistors in series with the coils to reduce the current, they will typically run at a significantly lower voltage than their rated voltage.

Whichever you decide, hope it works for you - it'd be interesting to know a bit more about the application!

Regards, Adrian

 

Hi Adrian, thank you for your detailed comment. As I’m new to Arduino I’m assuming I need to install the IDE board and the control board which is where I have the space problem. I will look into your suggestions and let you know if I can work with them. This is the last part of my project which is to control the revolving number plates in the Eaglemoss James Bond 1/8 model DB5.
I have also automated the machine guns with sound and flashing guns, the bulletproof screen, lighting and added sound effects.
A very consuming and mind testing project but as an AM enthusiast and owner for over 20 years really enjoyable. Peter

 

Hi Peter, there is no "IDE board" as such, you download the IDE (Integrated Development Environment) which is just software onto your PC and to program the XIAO you connect it to the computer with a USB cable. Whilst connected to the computer the XIAO is powered with 5.0V from the PC USB connection. When you remove the USB cable you will need an external power source, nominally 5V but it will cope with 9V or more because the XIAO has an on-board DC/DC converter to produce the 3.3V the processor needs. Here is a circuit I built to count the pulses from a variable reluctance sensor for an electronic car spark distributor from a crank trigger wheel. for scale the holes are 2.5mm or 1/10 in apart, standard IC spacing - 14 pin IC, overall more components than you need:


I'd recommend buying the SN754410NE itself, rather than a ready made board and build something similar to my VR sensor board. I've used sockets for both the IC and the XIAO.
And with the XIAO you could create machine gun sounds and flash LEDs - indeed every effect you describe. See https://forum.arduino.cc/t/8-bit-gun-sound-effects-without-extra-hardware/65317

 

Thank you Jerry for your comments, very thought provoking and informative. Adrian has suggested a solution to the steps issue but I feel it’s now going into overkill. I’ll give a lot more thought to my project but may just stay with the button jogging solution.
Peter

 

I’ve just discovered this article: https://howtomechatronics.com/tutorials/arduino/stepper-motors-and-arduino-the-ultimate-guide/
and the driver discussed is the A4988 which I understand has the following Step Modes: Full, half, 1/4, 1/8 and 1/16.
the driver board looks small as well.
So, if my thinking is correct, each revolution can now be 3,200 steps which means 1,066.6666 steps in 1/3 revolution. This is probably as close as I’m going to get with a 2 phase stepper.
Am I making sense?
Peter

 

Additionally I see the DRV8825 goes to 1/32 of a step = 6400 in 1 rev.