Almost found correct Microcontroller in store, but a problem. Need help please

Help & Support Robot Parts
1

So here’s my situation:

I currently have the 12VDC (variable) Brushed Gear motor (8 RPM): mcmaster.com/#6409k14/=qftu50

I have an aquarium controller that uses a Module called the VDM. It (controlled by the Aquarium Controller) uses 0-10V analog signals: neptunesystems.com/wp-content/uploads/2013/01/VDM_manual.pdf

I am trying to get my 12VDC motor controlled by my Aquarium Controller.

In my search, I discovered that my motor needs a Driver/Controller. After much searching I found this one: robotshop.com/en/pololu-18v7-7a-motor-controller.html

The Aquarium Controller Community Forum told me that is almost right, but:

"But the issue I see it that it only has an analog control input range of 0-3.3vdc. You’d have to reduce the 0-10vdc signals from the VarSpd outlet.

The big thing to watch out for is how much load it places on the VarSpd output - they can handle up to about 20mA"

Many of the controller in the Store here don’t tell me the analog control input range… does anyone know where I can find the appropriate controller?

I really appreciate any help I can get on this topic. I am pretty frazzled by all this searching I’ve been doing for this project. It took me four days to realize I needed a driver alone! XD

2

Hopefully this article will help:
robotshop.com/blog/en/how-to-make-a-robot-lesson-5-motor-controller-3695

3

Hi Electrobes,

If you want to convert a 0-10 volt analog output into a 0-3.3 volt analog input, you can use a voltage divider to divide the voltage by 3: a 10 volt signal becomes 3.3V, 5V becomes 1.7V, etc.

You can either build your own voltage divider with some simple resistors, or you can use this part and set the switch to position ‘3’ (and not ‘10’):

With this part, the internal resistance is 102kΩ, so the load on the 10V output signal would be incredibly small: about 98 µA (micro-amps).

We hope this helps,

4

Thank you so much Jeffrey! I think that may have solved my long time problem, at least I hope so!

Thank you again!

Christian

5

Cbenson - I have looked at that but am still confused. It got me through some of the selection of micro controllers, but a lot is left and I don’t know how else to proceed.