Today we used the serial/usb cable to talk with the opened sphero in shell mode using a small python script. It works so we know if we want to flash sphero via seria we will be able to use the uart.
We settled on reusing the hardware of sphero, but adding a pcb above it. The features we want to add is a spinning led bar like RoseAce, and some IR sensors, using maybe some IRDA to modulate the IR.
One architecture we could do is one board plugged on the uart of sphero, and a motor in the center of this board. On the axis of the motor just a bar or disc with some leds on it and powered by a “button battery”.
So we are sure to do an additional pcb but we don’t know if we will do our own firmware our just talk to sphere via the api mode.
Our next step is to succeed in flashing the sphero with our own code. But it’s scary because we have only one try, if we flash it with another code, it’s original firmware would be whiped and there will be no going back.
Our idea to check if we can flash is to code a simple application, for example with chibios, that just changes the led color (in order to check if it works). And then put the BOOT0 to 1 and BOOT1 to 0 to go in alternate bootloader, then use the stm32loader python code to flash over the serial.
If sphero boots and the led blinks it’s a green light!
We will try this as soon as we are confident enough to do that.