• mainly jesus and my hotrod

    Julien10/29/2020 at 14:33 0 comments


    Looks like you have a winner. Still two things to work on : force the PWM output to 0V at boot up and find out why the reptition counter register and the associated registers of TIM1 have trouble to be updated.

    Also I should find the proper timming for the PWM modes.

    the second revision could use a 5V microcontroller to avoid having a 5v regulator for a ridiculous cmos buffer.  There's a DPACK on the board because I have a tray full of them but  a SOT223 would do the job

  • fuel tester

    Julien07/29/2020 at 12:27 0 comments

    Nothing really fancy, the tester control the coil of the injector with different patterns. There's a few unit on the chinese market but they look pretty crap with their plastic case. This unit will be made for proper abusive workspace with a aluminium case.

    Originally I wanted to make a 4 channel unit to be able to do test pattern for all the injector at once. But I realised there weren't resistors but coils that control the injector pin. On my Daewoo car, the impedance is 15.4R which means a lot of current ! (some units are even lower) which complexifies quite a bit the desing if I go this road.

    The microcontroller is a STM32F0 that I have in stock in its SOP20 package. I added CMOS buffer to be able to use different kind of N-Channel mosfet to control the coil. Everything will be done with the PWM mode on the microcontroller that has an interesting "repetition" feature which is exactly what I want. 

    At the moment I still need to find documentation on the duration of the pulses depending on the condition (idle car, fast engine rev, ect...).