Cat Food Dispenser - Triple Auger Feeder

thingiverse

I have three cats and was trying to find a neat way to feed them all equal amounts at the same time elegantly. I got the original idea from kitlaan and ultimately decided on using a stepper-driven single auger with 2" PVC set up for three independent flow paths. I started with the Noodlepie1002 auger and removed the ends and a 1/2" core from the model. This was printed enough times to get the overall desired length. These were epoxied onto a 1/2" aluminum tube. In addition, the prints were coated in epoxy, sanded, and coated again to reduce friction and strengthen. Next, I assembled the PVC "T"s in such a way to deliver the food through three flow paths. The 2" PVC tubes that interconnect the T's were chamfered on a lathe to minimize any internal abrupt surfaces. (I'm sure this could also be done with a little bit of elbow grease.) The motor block was made to take any combination of NEMA17 or 23, with or without a planetary gearbox. I decided to go with a 1:5 NEMA17. Be careful not to use too high of a gear ratio. Some higher ratios like 1:100 can only deliver about 4Nm of torque before you risk damaging the gearbox. You would rather skip steps than shred gear teeth. The motor block has a small notch built into it. This lets you push-and-twist the block into place. If the twist to lock direction is opposite the auger feed direction, it will have a tendency to secure the motor block and prevent it from falling off over time. I've built a small wood enclosure/hopper for the feeder. This is aesthetic mostly and let's the whole thing pass the wife's inspection. It's 1/2" oak plywood with some trim and plexy sight glass. I don't have any plans for the enclosure. I mostly like to wing this sort of thing and with a healthy application of trim you can hide almost anything. Included are some pictures of my wiring diagram and a picture of the final prototyping board. I ran all the interconnects below the board to keep things neat and this is mounted inside the box near the motor. My code is included and has plenty of notes. I'm not a very good coder and need to comment EVERYTHING or else I forget after a month or two and edits need to be made. Similar to kitlaan's code, this moves the auger in the forward direction to deliver food, then back to un-jam, and repeats. However, unlike kitlaan, I use a stepper rather than a servo. I just finished the code and am about to test it out on the cats for the first time. I'll keep this updated with any changes. Feel free to ask any questions! Here are some of the parts I used: 1/2" Aluminum Tubing - https://www.mcmaster.com/#9056k65/=16im13o 1/2" ID Bearing - https://www.amazon.com/gp/product/B00VNVFY42/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1 Stepper Driver - https://www.sparkfun.com/products/12859 Arduino - https://www.adafruit.com/products/2000 Shaft Coupler - http://www.ebay.com/itm/171991954669 Stepper motor/Gearbox - http://www.ebay.com/itm/322128759561?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT Print Settings: Printer: Anet A8 Rafts: No Supports: Yes Resolution: 0.2 Infill: 20% Notes: Printed "pointing up". Post-Printing: Epoxy coating for smooth texture and strength.