Need help with pulse width modulation for motor for aiming laser pointer
The main problem I am having is that every electric motor I find has a RPM in the thousands. Such speed would jolt the laser to one side or the other without any means of fine adjustments in aiming.
I've looked around and it seems to be the general idea that either a PWM (pulse width modulation) controller or gear box are the best options to get lower RPM out of a motor. I don't have much room to work with where I want to mount the laser pointer, so I decided to go with a PWM controller and spread the components around the model to save space.
I've been doing my best to construct this....
... but my knowledge of circuitry is rather limited, having only take a college course on basic circuitry, I'm in a little over my head.
Could someone please identify the component labeled "PULSE WIDTH ADJ" (center bottom, between the two diodes) is it two 250K resistors in series with the lead to the left acting as a resistive load or something else? Also, what is the component labeled "IRFD024" (far right below the motor)
I would be very appreciative for any information that would aid me in getting a PWM controller to slow a motor down to around 50 RPM. If some one has a better idea all together, I would be willing to scrap the motors for another project and start from scratch.