Over the last few weeks, the hardware for three more rotors has begun to take shape. Below are some of the parts coming together. 

Clockwise from upper left are three clockwise blades (one completed, two almost complete), the cores for all of the counter-clockwise blades, rotor plates for three more rotors, including one with servo mounted, and the latest power module.

The goal is to have a second clockwise rotor ready for testing by the end of the week. The other rotors will be completed in the next few weeks.

The power module has been revised and a diagram was made to show the wiring.

Progress is moving forward on the firmware as well. The data transfer from the master node to the slave nodes (rotors) is working using UDP. Work is now focused on transferring the data from the flight controller to the master node. The initial concept was to use I2C, but it appears that the code for the ESP32 to act as a slave I2C device hasn't been implemented. CAN was my next choice, but the ESP-IDF doesn't have a driver. There is another Hackaday project #ESP32 CAN Driver that looks promising, but between that and having to write a custom driver for the PX4 Firmware, it's proably too much work for the time left. The Pixhawk2 has a wierd note about SPI not being recommended, so that was out.

So that leaves using UART for now. This should be relatively straight forward since 1) There's already a PX4 driver for sending PWM signals through the UART port and 2) The UART is fully implemented in the ESP-IDF and there are examples available. In the long term I hope to have multiple protocols to give the user multiple options.

So if all goes well, the firmware should come together in the next two weeks and then the control scheme with the Pixhawk in the loop can start being tested!