Week 5 - Pot Controlled Electric Motor

This week’s adventure was more of a challenge and more adventurous than previous weeks have been. This week, we were to choose our own circuit to build, then as a challenge, adapt or modify it in some way to make it more useful. At least, that’s how I understood the instructions.

So, with my personal project goal in mind, I chose to first build the electric motor control circuit and understand how it works. Then, when I had that working, after some hair pulling and backtracking, I decided to find a way to use the concept to include a potentiometer to manually control the speed. This, I felt, would give me a better grasp of what I would need to do to achieve a similar effect on the boosted board project I intend to try to build for our son.

Here's my video of Circuit 10 and a bit of explanation of what I did and the troubleshooting I had to go through.

At first, it looked like it was going to be quite simple: just choose one and build it. Unfortunately, after choosing the most likely looking prospect, I found that it would only barely function to adjust speed of the motor within a very narrow range, which did NOT include “off” or zero RPMs. So, I actually had to resort to a “Dummies” site to find a build that would actually work and make the motor run from 0 RPM to full speed, in this case 255 RPM. This build was actually much simpler than any of the others, some of which even included ICs (integrated circuits) which I wanted to try to avoid since the project will ultimately be intended for off-road use in rough terrain. I felt like ICs would be less likely to stand up to the vibrations and stresses of such use.

Here’s a screenshot of the code I used. It is actually very simple compared to some of the others that I looked at.

Here is a pic of the circuit. It actually looks quite simple.

Here’s the schematic I built from. Notice that this is the original, with the change annotated.

So, here is my version of the Pot Controlled Electric Motor in action.

Final Reflection:

This type of circuit is actually quite common in the real world. There are motors in nearly all appliances. Some of them (i.e. refrigerators, dishwashers, etc) are controlled exclusively through set program parameters while others (i.e. blenders, food processors, etc) are at least partially manually controlled. As I have mentioned previously, I intend to make use of this circuit to control the motor of the boosted board project that I want to build for our son. As it is intended to be an off-road, rough terrain vehicle, I prefer to stick to physical components that are more likely to withstand the abuse of off-roading, so no ICs.