Tank Bot
This instructable was created in fulfillment of the project requirement of the Makecourse at the University of South Florida (www.makecourse.com).
Supplies
- 3D Printer
- PLA Filiment
- 2x 28BYJ-48
- ESP-32S
- 2x ULN2003APG
- Jumper Wires
- HC-SR04
- 10 uF Capacitor
- 3.3 uF Capacitor
- L7805CV
Design the Tank
The first step of the was to design the Tank in Fusion 360. This took several revisions for the design of the tank and the treads. The design includes a few major component. The main body of the tank includes two holes for the two wheels to go into as well as holes on the front and back for LEDs and the HC-SR04 range sensor. The top of the Tank has a few separate pieces that go together such that it is easy to replace individual pieces and have different modules on top of the Tank. Lastly the treads are a single design that snap together and combine in a way that allow for variable lengths for them to be easily produced.
Electrical System Design
The next step is the design of the electrical system which is focused around the ESP-32S module which is an Arduino compatible board but is smaller, more powerful, and allows for Bluetooth communication. The ESP-32S sends signals to two NPN darlington sink drivers (ULN2003A) which allow for the higher current stepper motors to be driven using them. The power is delivered by a L805 5V regulator which takes in power from a battery and outputs a constant 5V. The battery used in the project was a 9V which was able to power the motors as well as the ESP-32S via the Vin pin as the ESP-32S is not 5V compatible.
Arduino Sketch
The Arduino Sketch can be found here:
https://gist.github.com/grant0417/6d701abdb5362e58...
The sketch has several main parts, it communicates with the phone via a library called Dabble, it drives the motors, reads from the ultrasonic sensors, and accelerometer.
Creating the Tank
First print the STL files on a 3D printer in PLA at .2mm layer height. The treads need about 74 produced and each side of the tanks requires one of each type of wheel so make 2 front and 2 back wheels.The actually assemble the Tank the electronics are placed inside and the motors and ultrasonic sensor snap inside into their respective locations. The motors should be further secured with epoxy or glue to ensure it is stationary. The back wheels snap snap into the two back holes and the front wheels push onto the side of the tank. Finally the treads go around the wheels.