| I used the MC3479 chip that is designed to drive bipolar stepper motors to drive my unipolar motors. This is a schematic of just one driver. |
| This is a way to hook up the home switch to one of the LPT inputs. |
| Preparing the board for etching. |
| This was definitely worth doing, because there are 0 jumper wires and it makes things work smoothly. I made sure not to use any flux paste due to very fine traces! |
| The TIP's typically require a heatsink, because they can get fairly hot and sometimes fry. My solution was to create an air tunnel to maximize the air flow. |
| This version obviously was too compact. The TIP's were too close together, so they did not allow effective cooling. The worst problem was that I used flux paste, which acted as a small capacitor and created noise. This was very hard to detect since the flux paste did not short the contacts. |
| Another version using a larger perfboard almost worked. Unfortuntely, at this point I still did not know about the flux paste problem, so I was getting noise issues again. This was an attempt to spread out the TIP's and to use larger diodes. |