Week 4: Finishing Up

This weeks activities

This week was all about finishing and cleaning the machine up to look as presentable as possible. We started by soldering all the components onto a pcb board up as shown by the circuit diagram above. We opted to use female pin headers to interface the stepper driver, microcontroller and buck converter, as these components are the most likely to fail .

  

The lines from the TMC2208 symbol represent the wires going to the motor. The global power for the circuit is 24v and it is stepped down using to 3.3v using a dc-dc buck converter for the portion of the circuit that requires 3.3v logic. This is mainly the sensors. Looking at the schematic, you find it odd that we have connected the 5vin of the lcd to the the 5vin of the teensy 4.0. Vin on the teensy 4.0 is connected directly to the usb 5v bus, so when the teensy is connected via usb, the vin acts as a 5v output. The only device on the circuit that takes the raw 24v is the tmc2208 motor power input VM and a small cooling can that is not shown on the schematic. We also used jst connectors to connect the sensors , stepper motor and magnetic encoder which enabled us to disconnect the "brains" of the machine for easier mobility when programming

Next we designed separate enclosures for the control portion and the display portion:
 

Because this can be used as an educational example when teaching the concepts of PIDs we aimed to make the system as user friendly as possible by designing a menu for the LCD system. It is a simply menu that displays one start button when the system is booted. Clicking this start button using the rotary encoder initialises the system and begins the PID loop. It then displays the parameters of the         systems P, I,D and Setpoint , all of which are changeable and updateable in real time. 

Finally we began the process of tuning the PIDS to get a stable response. 

Project Title - 1 Dimension Pid Ball Balancing System
Team Members - Samuel Frimpong /Yuhao Fang
Academic Advisor - Mohammad Hasan