I’ve received a few emails asking about buying or for help making the Pro300 PT to ANT+ adapter. I wanted to be as candid as possible and say that I would like to complete the development of version 2 before producing any more PRO300 PT to ANT+ adapters. The primary reason for the V2 is to address the limited memory that is available in with the ATmega32U4 processor.
As I wrote the current code, The Adafruit_GFX and Adafruit_SSD1306 libraries used to drive the OLED display are rather memory intensive. I found myself resorting to various tricks to get the memory usage of the ANT+ code as small as possible to get the system to run without issues. This did lead me to the neat F() syntax for storing strings in flash memory rather than RAM.
With a basic working system behind me it’s time to switch processors and compile all of my learning into the V2 board. I chose to stay within the Arduino ecosystem as the abundant well tested libraries makes development far easier than when I use to work in CCS PIC.
Processor comparison
| Pro Micro ATmega32U4 | ESP8266 |
|
|---|---|---|
| Program Memory Size (KB) | 32 | 4194 (external flash) |
| CPU Speed (MIPS/DMIPS) | 8 (3.3V) | 80 |
| USB Output | Yes | No |
| Estimated Cost | $4.50 | $2.00 |
The built in WiFi is a nice addition i’m sure I will find uses for in time. I have plans of turning the Pro300 PT into a smart bike and controlling it via FE-C (Torque control method TBD). I have working software on the V1 prototype board without the OLED display but ran into memory limitation as I tried to pull it all together. Leading down the current path of moving to a new processor.