We have produced a version 1 of the product (RobotCar HAT v 0.9) based on our initial experiences. As with all initial products, there were one or two minor issues with it, but on the whole it worked very well for what we planned to use it for. We also saw the opportunity to massively improve the design, to allow for a better user experience.
After this board, we immediately started work on the second prototype. The second prototype is still in development. We have completed the schematic drawings for it and plan to develop the PCB layout and fabrication over the next two weeks. We are very happy with this second iteration of the board as it has an expanded feature set and much better functionality compared to the first prototype. Below are the new features added from version 1 to the version 2 board.
Features - Sensors
INA219 Current Sensor
NEW: IMU (9dof) Accel, Gyro, Mag
Features - Compatibility
Arduino IDE Ready
Features - Connectivity
Easy Pi-HAT Format - Ready to Deploy
On-Board Voltage Regulator for Raspberry Pi boards (no external power)
2 MB Flash Memory
Mini-Tamiya Connectors for Battery and ESC connections (designed for RC Cars)
Redundant / Backup Battery Input for Raspberry Pi / M0
Breakout for additional I2C sensors and devices
Brushed and Brush-less ESC compatible (through PWM)
NEW: USB to Serial Pass-through to communicate with Raspberry Pi 'in the field'
NEW: 4 x 16-bit (configurable) High Resolution Servo Outputs
NEW: 4 x RC Controller Inputs
NEW: 15 x General Input/Output ADC PWM
NEW: 2 x Raspberry Pi Control Pins (through M0 -- configurable) for Power Management and WiFi Config.
NEW: NeoPixel Controller (through M0)
NEW: High-Accuracy IMU with 9-degrees of freedom
Work on the software is starting this week as well, and we expect to have two different ways to interface with the board on launch of the campaign:
SeeSaw Library - This is a library that is open-source provided by Adafruit Industries for interfacing with any I2C board. We plan on using the existing firmware tools by writing our own configuration specific to the RobotCat HAT. This library then uses CircuitPython running on the Raspberry Pi to control external servo motors and other sensors.
Custom CircuitPython Script - we plan on using CircuitPython to write a script that emulates the actions of a PCA9685 which is used widely by the Donkey Car Community. In this script, we will be able to employ custom actions such as direct control of the servo motors by the RC controller Input pins (removing all latency from control) and safety features such as detecting a stall when too much current is drawn from the battery.
We should be able to provide you another update in two weeks time with the latest developments.