My Robot is Hardware Complete!

 Finally I have everything assembled and wired up!

I realised my directly soldered wires were prone to snapping off the PCBs, and I needed headers to plug my servo motors into. Just having a pair of signal wires coming of the Motor2040 board was not going to cut it.

My solution was to design some additional brackets to bolt an I2C distribution board onto. A PCB I designed after Pi Wars 2019 but had never actually used on a robot until now.

This board has 4 pin sockets for I2C breakouts, along with some 5 pin sockets intended for the Pimoroni Breakout Garden boards which use a 5th pin for some other signal functions. This 5th pin for each of these sockets is connected to a header on my board. In a flash of inspiration I realised I could cut the power track to these 5 pin sockets, and by sacrificing 2 of these 5 pin outlets I could wire one of the spare 'signal' pins to V+ from the motor supply 6V line and one to GND. Then I could feed the servo supply voltage, GND and the RX and TX signals into this signal header and supply each of the remaining 5 pin sockets with high current power, GND and the signal line needed for the two servos. An extended custom lead crimping session saw the 2 servos converted to custom 5 pin JSH-PH plugs. A custom lead to supply the power and signal inputs to the board, and my servos were connected!

All that remained was to connect up the I2C input to the Motor2040 board and plug in my sensor and IMU and I was done. It was late in the evening the night before my week long family holiday and my robot was read to take away and maybe do some coding on in the evenings. Then the QWIIC socket broke off the Motor2040 board as I plugged in the final connector. I realised I it was too late to take everything apart again, and took the sensible option of going to bed to sleep on the problem.

In the morning, alongside final packing I managed to take apart the robot to remove the Motor2040 board. It has headers which can take a Breakout Garden socket (too large for the space I had) but also due to an extra GND pin on the header, could take a 4 pin JST-XH socket. Genius on the part of Pimoroni, or just good luck? Either way I was able to solder on a socket and crimp up one more custom lead and pack it all in my bag to take on holiday.