BlueESC

The BlueESC is a simple, open-source electronic speed controller for three-phase brushless motors. It is designed to run the SimonK firmware on an Atmega8 microcontroller.

The hardware is licensed under GPLv3. It was inspired by and draws from other open-source ESC projects including AfroESC, WiiESC, and others. We owe a big thanks to everyone who has shared their open-source ESC designs and firmware.

We also thank Bernhard Konze and SimonK for the tgy firmware. Please see the firmware license at the top of tgy.asm. The firmware configuration files for the BlueESC are maintained in our fork of the tgy project.

##Features

• Atmega8/168 microcontroller
• PWM, I2C, and serial signal interfaces
• 5-22 volt input (2-5s lipo)
• Reprogrammable via PWM pin using bootloader
• Status and warning LED indicators
• Sensors for voltage, current, and temperature
• No battery-eliminator-circuit (BEC)
• N-Channel MOSFETs

##Rev.1-2

The first revision was designed as a proof-of-concept. It is designed on a simple 2-layer PCB and space is not highly optimized. It exposes all interfaces and programming pins.

###Specifications

• 5-16 volt input (2-4s lipo)
• 25 amps continuous current (not yet tested)
• Dimensions: 41mm x 57mm (1.60" x 2.25")
• MOSFETs: Vishay SiR158DP (N-channel)

##Rev.3-4

The second major revision is designed to work with the BlueRobotics T100 Thruster. It is highly compact and is potted in an aluminum enclosure that acts as a heat sink. The board is built with two 2-layer boards, one for the power electronics and one for logic. The boards are connected by headers. This allows components to be placed on three sides, simplifies design, and minimizes cost.

###Features

• Hall effect current sense IC
• Thermistor temperature sensor

###Specifications (subject to change)

• 6-22 volt input
• 25 amps continuous current (air)
• 35 amps continuous current (water)
• 400 uF decoupling capacitance
• Enclosure diameter: 40 mm (1.58")
• Enclosure length: 18.5 mm (0.73")

##Firmware Compilation

The BlueESC uses the tgy firmware located in the BlueRobotics fork.

Mac: (Uses Homebrew)

brew update
brew install avra
make bluesc.hex

##Initial Firmware Flashing

The BlueESC can be flashed using any AVR ISP programmer.

avrdude -c [programmer] -p m8 -U flash:w:bluesc.hex:i 

The fuses should be set per the instructions in the tgy instructions.

avrdude -c [programmer] -p m8 -U lfuse:w:0x3f:m -U hfuse:w:0xca:m

The Rev4 version of the board does not include an ISP header or pads. The microcontroller must be flashed with a special tool that connect directly to the microcontroller pins. Make sure that the board is powered when programming.

##Firmware Flashing Through Bootloader

Once the ESC has had the firmware (including bootloader) flashed the first time, it can be reprogrammed subsequently through the PWM input pin using a programmer like the Turnigy USB Linker or the AfroESC Programmer. This can be done through the Makefile in the tgy project as follows.

make program_tgy_bluesc

It can also be done with avrdude and the compiled hex files as follows.

avrdude -c stk500v2 -b 9600 -P [programmer port] -p m8 -U flash:w:bluesc.hex:i

##I2C Commands and Address

The I2C message format allows speed and direction to be set and voltage, current, rpm, temperature, and status to be requested.

###Speed Command

• cmd: Command, sent as int16_t. Acceptable values in range -400 to 400.

####Bytes

• Byte 0: cmd_h
• Byte 1: cmd_l

###Data Request

• voltage: Sent as uint16_t in millivolts
• current: Sent as uint16_t in centiamps
• pulses: Sent as uint16_t in pulses per second. Divide this value by "magnet pole count" to get rev/s.
• temperature: Sent as uint8_t in degrees C
• status: TBD, bitmap sent as uint8_t

####Bytes

• Byte 0: voltage_h
• Byte 1: voltage_l
• Byte 2: current_h
• Byte 3: current_l
• Byte 4: pulses_h
• Byte 5: pulses_l
• Byte 6: temperature
• Byte 7: status

##Releases

##Video