How to control motor (1.5 V at about 0.5 A) with Particle Photon using optocouplers and transistors?

Question

I’m trying to control a motor that runs at 1.5v at ~0.5A using a Particle Photon. I’m powering the Photon over USB (for now, at least) and the motor with a AA battery. I’ve tried designs based off this schematic (modified to power the motor with the battery) but ended up with unacceptable noise in a separate circuit connected to the Photon. I’ve also tried this design without success. I’m a total noob at this stuff so any help would be appreciated.

I have an inexhaustible supply of resistors, a variety pack of transistors and diodes, some small capacitors, and PC817 optocouplers at my disposal (along with some other misc. components).

I’ve read this but most of it went over my head.

Answer 1

fortunately the noise of a motor with these specs is easy to control. the figure 5.2.5 in the second link, works fine. but I assume you have connected both grounds together. it should be connected like this :

^{simulate this circuit – Schematic created using CircuitLab}

this way, there is no physical connection between motor control and logic circuits. but there are some notes:

• a tiny relay would work without much hassle.
• the transistor should withstand at least 1amps for a safe margin.