Progress on the Renesas/Eco Solar Breizh solar race car

This is a brief post to prove that the Solar car has progressed from theoretical concept drawings to real hardware. The two previous blog posts described the design for the electronic control system based on Renesas microcontrollers: RX63N for the central computer, R8C for the Modular/Sensor boards and the RL78 for the energy-harvesting ‘zero-power’ structure monitors.

Central Computer

A PCB for the central computer has been designed and the prototype is fully operational providing:

Dual CAN buses

2.4GHz wireless communication with a supervisor vehicle (following the solar vehicle during the race).

Bluetooth communication with an Android tablet controlling the solar vehicle (lights, speed, power, temperature management, etc.).

Wide power supply input range: input voltage can be between 60 to 72V (DC/DC converter on board) from batteries.

Back-up battery for data storage.

MicroSD Flash card slot (for data logger).

Small LCD for technician intervention (only for debugging).

Dual USB provides back-up communication with computer for debugging and with Android Tablet in case Bluetooth is not working.

Dual power output to drive the two motor controllers.

Accelerometer and Temperature sensor.

12V power supply distribution to daughter module boards.

A low-cost but powerful development tool for the RX63N microcontroller is the GR-Sakura board obtainable from RS Components, Product Code 761-6778. It has an Arduino™ format and free software development tools are available on-line ‘in the Cloud’.

Other systems are under development or being tested for endurance. One in particular I hope to talk about in more detail in the next post is the structure monitoring sub-system based on the RL78 microcontroller which relies on harvesting energy from suspension movements to power itself.

Meanwhile the bodyshell is looking good, although the transparent bubble canopy design had to be modified to meet WSC expectations for driver vision.