Arduino test bench project (looking for discussion)

Projects General Guidance
1

I'm having an idea about making universal test bench for motors, encoders, analog outputs and so on.

I have breadboard at work, but sometimes it sickens to connect all circuit for simple test.

My test bench would be really simple: few basic sketches to upload in arduino for unipolar, bipolar steppers. Some digital I/O's, 8: 0-5V, 4: 0-10V, and 4: 4-20mA analog inputs.

Some PWM outputs. and AO's (4-20ma) Just thinking about it, gathering information ( 4-20ma output from Arduino - General Electronics - Arduino Forum )

Of course some communications.

Bugget lets say unlimited (but in common sense of course) :smiley:

Questions would be:

a) any usefull shields for mottors up to 10A? No microstepping, wave form, half step and so on necessary. Just plain C/CCW rotation
b) any ideas about other kind of jumpers than http://www.ebay.com/itm/120pcs-20cm-2-54mm-1pin-Jumper-Wire-Dupont-Cable-for-Arduino-/251314138553?pt=LH_DefaultDomain_0&hash=item3a837d6db9 ? I understand that those will be used for signal transfer between arduino and bench shields.
c) maybe something else that could be added??? I thought about LCD, but when you have a terminal it kinda loses purpose for data.

I'm familiar with small amount of arduino shields thats why I'm asking for help

Bless you if you read it all :smiley:

2

Why go for ready made shields? Wouldn't this be an ideal opportunity to make something totally unique and tailor made to suit your demands.

Start by designing the layout of your inputs, outputs, displays, controls etc.. then work on the circuits required to make your concepts work.

3

Yeah, I understand the point.

Probably I will have to design my own stepper drivers. Probably in a few days I will probably display concept design of whole bench.

At first I ask for help to design bipolar/ unipolar stepper driver. I have connected them separately, but does anyone have idea how to make universal one? I would like just to replace few jumpers :slight_smile: is it possible?

For bipolar I used: http://www.powerguru.org/wordpress/wp-content/uploads/2012/08/A-Bipolar-Stepper-Motor-Drive.jpg

Unipolar driver only needs 4 transistors

4

What is the purpose of the test bench?
Is it a platform for testing software?
OR
Is it a platform for testing hardware to ensure that the hardware works properly?

If the purpose is just to test potentially faulty hardware I see no problem using DIY interfaces and test software as long as they properly match the hardware under test.

If the purpose of the platform is for testing software then I think you should NOT use DIY interfaces because they may not behave exactly like the interfaces that are generally used by Arduino users.

For example a "universal" (unipolar / bipolar) stepper driver will not have the normal facilities that a specialized bipolar driver will have and will not represent a proper basis for provide stepper software.

...R

5

Very good point. At first I thought only about testing hardware, but when you mentioned maybe in the future me or maybe my colleagues will have a need to test software. So in that case probably there should be 2 prepared slots for steppers.

6

Robin2:
For example a "universal" (unipolar / bipolar) stepper driver will not have the normal facilities that a specialized bipolar driver will have and will not represent a proper basis for provide stepper software.

are you talking about something like that? Pololu - A4988 Stepper Motor Driver Carrier I didn't completely follow that part

7

KarolisL:
are you talking about something like that? Pololu - A4988 Stepper Motor Driver Carrier I didn't completely follow that part

Yes - but not necessarily that specific part. You need one that can handle the current required by the motor you want to test.

...R

8

Yeah, I undertand, I just gave that as example. I think I will make 2 drivers: 1 for unipolar stepper and second for bipolar/ dc motor.

Newt question would be, how can arduino read 24V encoder signals?

9

KarolisL:
Newt question would be, how can arduino read 24V encoder signals?

If your encoder produces a 24v output signal (i.e. a signal that is between 0v and 24v) just use a pair of resistors as a voltage divider to reduce it below 5v for the Arduino.

(Is that newt like an electric eel ?)

...R

10

I understand that, but, but I would like to make galvanic isolation. But maybe it can be solved by using optocouplers?

Something like that? http://forum.allaboutcircuits.com/attachments/ttlto24vtottl-png.4692/

11

KarolisL:
I understand that, but, but I would like to make galvanic isolation. But maybe it can be solved by using optocouplers?

Opto-couplers sound like a good idea but I have no experience of them myself.

...R

12

I haven't done anything with them by myself, but as I understand there are 2 factors. Diode forward voltage, and current through transistor. My local vendor supplies optocouplers with different forward voltage. As I understand with different voltage I would have to adjust different resistor value, thats all.

Am I right?