First I’ll give the hardware update and then the electrical.
For this project to work right, I need to be able to roll the dough out on the pan and have it come off well when it’s done cooking. So I went to the store and bought a non-stick mat. The dough rolled out really well on this mat, but the mat did not stay on the pan. So I made my own pan out of a galvanized steel sheet. I cut the mat a little shorter than 11”, cut off the corners of the steel sheet, and bent the edges of the steel around it.
I re-did the roller set-up. I mounted two rods vertically into the sides of my base for everything to slide on. The roller has two holes on the ends for it to move along the rods and a tree nut in the middle for the screw to control how it moves up and down.
I mounted the motor above the roller to a block of wood which also sits on the rods. The rods are threaded at the top and there are nuts that hold this upper board in place.
I figured the best way to attach the screw would be to weld it to the motor shaft, but I’ve never learned how to weld. So JB Water Weld seemed the best option for me. It is a putty that hardens and is water resistant. The roller moves up and down quite well.
Since I was running out of time (and materials), I had use the rods that were originally intended for the x-axis. I then used the rolling pin rod for the x-axis. This proved to be a good decision because it was already glued into the handle and made it much easier to attach.
For the z-axis, I decided that I didn’t want a drill bit cutting into my cookie dough because it would leave a bunch of little bits of cookie dough all over. A better solution would just push the dough out of the way. For this I decided a small hex wrench would be perfect. I bent it straight and pushed it through the end of a nifty little nut I found at the hardware store. I used JB Water Weld to hold it in place and connect it to the shaft of a DC motor.
After deciding to ditch the oven control, I went back to working with the motors. When I first tested the motors out I had gotten it to work, but I realized that I needed to set the current limit. So I looked up a youtube video and calculated my Vref to be 1.12V. I had previously disconnected the motor, so I re-wired it properly and went forward. This time, instead of moving, my motor just beeped at me. A really loud long beep. So I switched out my motor driver board with a different one and my motor just vibrated. I tried adjusting the current limiting potentiometer, but I'm pretty sure I broke it. I thought that maybe I had my wires connected wrong, so I switched them and stuff started smoking again. I ordered new driver boards and motors, but they haven’t arrived yet. So on the hope that it might still work I kept trying. I tested everything, and finally I decided to test the motors by driving them manually. Only one coil would work. Finally I realized I had a broken wire. I just didn’t know because, on the outside, it looked just fine. After I replaced that wire the motor moved. Then I went to test out the driver boards and found that I really had done bad things to them and only one would work.
I didn't finish. I got close, but I couldn't get replacement parts in time. When I do finish, I'll post about it even though it won't count for the competition.
I have learned so much through this project. I'm really grateful to have had this competition because it pushed me and gave me greater confidence.
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