SixBright

SixBright is replacement firmware for the HexBright flashlight.

SixBright's design goals are:

• Feature parity with HexBright factory firmware.
• Pure AVR C using avr-gcc and avr-libc (no Arduino dependencies).
• Higher quality firmware with clear code, precision PWM control, using a watchdog, power management, and modern software engineering techniques.
• Simple serial communication for monitoring programs (ex: temperature and charge status).
• Cross-platform host support with first-class Linux support.

Requirnments

• avr-gcc
• avr-libc
• avrdude
• GNU make

These can be installed on an Ubunutu Linux system with:

$ sudo apt-get install build-essential gcc-avr avr-libc avrdude

Building

To build the firmware, run make:

$ make

Programming

"sixbright.hex" is the firmware file to load onto your HexBright. Since the HexBright uses an Arduino compatible bootloader, any Ardunio programming method should work. The included makefile has "load" rule to do this with avrdude:

$ make load

This rule expects the HexBright to be on /dev/ttyUSB0 by default. This can be changed with the PORT make variable, for example:

$ make PORT=/dev/ttyS0 load

Note: On Ubuntu, and many other Linux distributions, regular users must be a part of the "dialout" group in order to write to a serial port. Add your user to this group or run "make load" as root.

Serial Protocol

SixBright will send periodic updates via serial when USB is attached. This section describes the format of these messages.

Messages are plain ASCII text. There is one message per line. The End-of-Line is marked by CRLF (\r\n).

Temperture

Format: 'T' [SPACE] {temperature}

Example: "T 55"

"temperature" is a positive integer from 0 to 255. It is the raw conversion of an 8-bit ADC. The MCP9700's outputs a voltage of:

Vout = 10mV * C + 500mV

The ADC conversion is:

ADC = Vout * 256 / 3.3V

The resulting formula for converting a raw ADC value to Celcius is:

C = ((ADC * 3.3 / 256) - 0.5) / 0.01

Note: the MCP9700 is a cheap sensor usable over the range of 0C to 70C +- 4C. Do not expect precision temperature reports.

Battery Status

Format: 'FULL' or 'CHARGE'

SixBright will report FULL when the HexBright is charged. If it is charging, then it will report CHARGE.