DIY data collection (with link to working code for Arduino and Bluetooth )



  • show someone a link to the working code for arduino, please. It was written in the title, but I don't see it
  • Difficult to say without code
  • Sorry for the late reaction, but the links to the code still work for me. On page 2, there are links to version 0.75. You need to read on from there, to fix some small errors.
  • Reviving an old discussion... We still use this old DIY device, but now with STM32CubeIDE rather than Arduino. Here is a recent on-board video with overlay ((warning: It's loud so adjust your volume)): . This is on a bumpy track with fast turns, 360 deg turn, hairpin turn, bridge, tunnel, a jump and approx. 90 km/h average speed.
  • Outstanding DrMotor

    Are you so kind to share source code and possible schematics, maybe even schematics?

    Possible by Dropbox?



  • Hi,

    First of all, great work! Thanks to all who have contributed to this. Great to know there is some kind of alternative to the (expensive) monopoly of Alfano and MyChron!

    I am interested in getting something up and running for my son who races in cadet katrs.I am initially interested in RPM measurements so that I'm better able to set the gear ratios.

    I've read through the thread and had a few questions about 0.75b. I'm new to this so please forgive the basic questions!

    1) For those who've implemented this, do you have your phone attached to the kart steering wheel? What did you use to secure the phone to the kart steering wheel?
    1a) If you don't want to use a phone, is it possible to store the dat to a SD card and then retrive it later for analysis in racechrono?
    2) I'm looking at the drawing and just want to understand what the black circular/cylindrical discs are? Are these the ferrite filter beads? Sorry if that's an obvious question!
    3) I intend on using this on a kart, would a LiPo battery as power source suffice?
    4) What's the purpose of the schottky diode? Is it to reduce noise signals when readiing the RPM signals?
    5) Can a Teensy be used instead of a STM32F103? Any benefit in using a Teensy over a STM32F103?
    6) What kind of breadboard did you guys use for the prototype?
    7) What kind of breadboard did you use for the final product?
    8) What kinds of enclosures are you guys using? Any links or pictures?


  • edited August 10
    Nice that someone is still interested in this old project :-) ...much time and many changes since that 0.75b, but I still use it. My latest updates are here:

    1) There are some pictures in the Mech-folder.
    1a) I use a phone on the steering wheel because of delta-times helps for improving lap times. SD-card and many things are possible -- one can even use wifi for telemetry to a track-side phone (but that is not according to karting regulations).
    2) you don't need those -- it works fine without
    3) yes, and see 1)
    4) voltage spikes from the ignition can damage microcontrollers (and also cause noise on other channels)
    5) Teensy, it has a NXP, right? I have only compiled the latest code for a WeAct BlackPill with STM32F411. If you are not happy with F1 of F4, then I think it might be easier to select another STM32 than a NXP.
    6) I used a strip-board (PCB with copper stipes)
    7) what final product? I guess -- no breadboard for a "final"
    8) see Mech-folder

  • Thanks for taking the time to respond DrMotor and apologies for not responding sooner! I've started to take a look at what you have in the github repo and that's awesome! I think I'll stick with the WeAct BlackPill with STM32F411. There's some long lead times on AliExpress so might take me some time to acquire all the items.
    Out of interest, when you were testing the RPM signals, did you always test directly on the kart engine or did you ever use some kind of simulator when/if the kart was unavailable?
  • @jade about testing:
    I only tested RPM with the kart, but it should work also on other noisy gadgets like a mower/trimmer/blower/chain saw.

    AFR/Lambda was tested on a car (4 stroke).

    The WiFi / ESP01S was used after updating AT-firmware, I think it was V2.2.0
  • Ok Thanks. I'm a bit confused as to should I now solely refer to the 911RSR repo or should I use it conjunction with 0.75b?
  • Try to follow the 6 points at the last section in the file. It is more complicated than Arduino.
  • Ok. Thanks. One more thing, I know you mentioned that you are using a rugged phone (Oscal S80), but I would be using my iPhone. I have read in several places that the vibrations from the kart would just wreck the iPhone and that it's a bad idea to try and secure a phone to a kart steering wheel and to just use a MyChron instead! e.g. -
    The thing is, there aren't any cheap MyChrons (even a MyChron 3, if you can find one for sale).

    I don't intend on using the camera whilst the phone is on the kart. I didn't want to buy another phone as I'm trying to keep costs down so that the overall price does not approach the cost of a MyChron.

    I'm not sure if I'm best not using my iPhone and somehow trying to get hold of an old phone which is still powerful enough to run RaceChrono?
  • I have had old phones (not iPhone) on the wheel for >10 seasons, and never lost one to vibration damage. I even had a kart jumping up/over and leaving tyre marks on the middle of the screen. The phone was still OK, but many other parts wrecked, including the steering wheel. Welcro tape is OK as vibration damper, ducktape and/or cable ties for safety....

    That Oscal is waterproof and its battery lasts "forever" (some weeks between charging).

  • Thanks! Glad to know you've not had any issues with vibration damage in 10 years. Sounds like I should be fine! That must have been quite a moment having another kart jumping up and over as you described....That Oscal sounds awesome!
  • Nice to see this is still active. I never got mine beyond the prototype stage, so probably a nice project for the coming winter.
    I like your approach and the scope of the add-ons you used!
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