1Preparing all material
- Laser cut
Download the pdf file, arrange some 3mm and 6mm mdf then 2.8mm acrylic and cut the parts!
I've organized the files in a bed of 40x80cm because is the size of the machine I had.
All other hardware parts are pretty easy to find according to the description at the BOM. The only item easy to mistake is the continuous rotation motor.
I've bought 28 motors to assembly 7 machines, turns out they delivered 19 motors of a model and 9 different ones, so be careful!
The motor we're looking for works rotating in one direction when receiving a signal equivalent to 0deg (1ms high and 19ms low), to the other direction when receiving 180deg (2ms high and 18ms low) and stops when sent a 90deg (1.5ms high and 18.5ms low) signal. It means it doesn't have any feedback control.
It's possible to use the version with feedback, but in this case the software is different and there is no need for the Hall sensor. Actually would be even easier to use only the version with feedback, but for me was harder to find, so I've preferred to use only the one without the pot.
Issue here is that suppliers don't rely on two different versions, they sell as the same product.
I've tried to remove the pot and add two resistors with same value to cheat the feedback system, but it didn't work well. This motor takes longer to understand a new value and is hard to rotate a single turn. Beyond that even using 1% resistor it doesn't fully stop when sending a 90deg signal. A simpler solution would be just make a different code for this feedback motors, but I was trying to avoid this solution because I needed 7 machines with exactly identical hardware.
Anyway, this issue has several solutions, just be aware of it. If you want to follow this project as it is, choose for the non feedback version.
An image says more than 100 words, so I'll post some images about the proper order to assembly it, but isn't hard at all.
1. Start by the middle wall, pay attention on the parts orientation, is quite easy to assembly in the wrong side.
2. Put the horizontal divisions.
3. Now the vertical divisions.
4. Add the motor and sensors support.
5. Connect one of the sides.
6. And the base (keep the Arduino holes at the back).
7. Use two M3x16 screws, nuts and washers to secure the display. At this point is good to notice what is the display orientation, some have the cable up, some down, some at the side. In this case the cable were down.
8. Connect the other side and hold the LCD.
9. Now the top clean acrylic.
10. And the top mdf.
11. Now add some tape just to hold it and put all M3x20, nuts and washers.
12. Use the servo support and fixate the regular 9g servo (not continuous rotation).
Tip: Set the maximum angle clockwise as the picture bellow and screw up the plastic part as the photo bellow. I did that later and was way harder to screw.
13. Use two M3x16, nuts and washers to hold the Arduino.
14. Add the mdf window frame and acrylic front plate.
15. Stick the keypad, put some good quality double faced tape in the RFID. I also preferred to extend the cables at this point, later will be hard to put the hand inside the machine to connect it.
16. Use some washers as spacers to add some tolerance for the sliding door, then screw the front mdf place using M3x20 screws, nuts and washers.
17. Bend the Hall sensor, hook up some cables and use plastic tights to keep them in place.
18. Use one of the screws that came along with each servo and fixate all four continuous rotation motors.
19. Assembly the PCB and connect it all!
- If you're willing to use my pcb and code, connect as the image.
- If you're lazy as me to crimp connectors I advice you to buy some ready made Arduino cables, female-female and male-female, I needed to assembly 7 machines and I'm glad I bought those ready to use cables.
21. Finally add the back cover.
Note: I highly recommend you go to the programming step and assure all hardware is functional before tightening this back cover.
22. Put a spring in the servo holder, add the magnet and screw all springs to its servos.
Note: this step still not complete because I didn't find a good reliable and digitally fabricated spring. I'm working on it.
3First code test
For Arduino UNO control board
- First download the compressed folder called "vm01" which is the hardware test code;
- Install the MFRC522 library on the Arduino IDE;
- Download and run.