Arduino have just announced a bunch of new boards, including one with an on board FPGA chip (plus a SAMD21 Cortex-M0+, plus an ESP32 WiFi and Bluetooth Module). A Field Programmable Gate Array (FPGA) chip is possibly the most impressive piece of electronics going. They are essentially a way of creating entirely custom digital electronic circuits (resistors and transistors) all inside a tiny chip, and completely reprogrammable – genius!
See more about the Arduino Vidor CAN bus support after the break.
I’ve been writing some software for a Wifi based CAN data logger for the ESP8266 in the Arduino platform, and have been getting a bit of a strange error. It appeared to be related to using the std::string functions in my code – and although I have used this in other sketches without issue, I suddenly received the following error as soon as I simply declared a std::string variable:
c:/users/scott/appdata/local/arduino15/packages/esp8266/tools/xtensa-lx106-elf-gcc/1.20.0-26-gb404fb9-2/bin/../lib/gcc/xtensa-lx106-elf/4.8.2/../../../../xtensa-lx106-elf/bin/ld.exe: C:\Users\Scott\AppData\Local\Temp\build525647f6f8500d071cfab5cccf314276.tmp/ESPCANLogger.ino.elf section `.text' will not fit in region `iram1_0_seg'
I have been busy over the last few weeks with various things, but have now completed most of the practical work on my project and am now at the stage of writing up the report/dissertation. I have successfully managed to achieve closed loop ignition timing control by using the Stellaris Launchpad development board to directly interface with the optical encoder on the engine and the pressure sensor charge amplifier (this replaces the AVL IndiSet 620 in my system).
ECU in black on left, angle of peak pressure and optical encoder interface on right. Connected together via serial
Just a quick one on what I’ve been up to the last few days. I now have the engine set up inside so that I don’t have to keep pushing it outside or waiting for the rain to stop. I’ve also set up an optical encoder, in-cylinder pressure sensor, and AVL IndiSet high speed data acquisition unit to capture data on a 0.25 degree crank angle resolution.
More progress made today, I connected up the alternator to the engine to begin testing it under load. This was pretty successful, and the ECU all performed as expected, with only a few tweaks to the PID controller parameters to improve the AFR control. I restricted the range of fuelling down to as restricted as possible to prevent the system setting wildly large or small fuelling amounts under certain conditions. I finally managed to get the PID to maintain the AFR slightly rich within a few percent under steady state conditions.
I have now managed to run the engine with electronic fuel injection (EFI) and electronic ignition, both controlled from my ECU. I’ve also managed to run in closed loop lambda control to maintain the correct air to fuel ratio.