Hi Chuckster! I was kind of hoping you'd chime in here. I was interested in hearing what you had to say about this.
In the great tradition of scientific discovery
, I stumbled across the idea of supplying the sensor wire with a continuous waveform by accident, and I was fortunate enough to learn what was going on and harness that information. I originally attempted to use a microcontroller with a bunch of fancy code to sense what the stepper motor was doing and adjust the voltage output being fed into the sensor wire, but that was a catastrophe. It's a long story of repeated failures that lead to the eventual discovery.
I have not tried a sine wave yet. I have modified the frequency somewhat though. It was actually substantially faster when I originally made it. I slowed it down and it has become more reliable in it's current version (pictured above). I suspect sampling rate issues were (are?) being encountered. That's why I'm considering an attempt to slow it down more. At the moment I just don't have the electronic components on hand to do so.
I too am generally of the opinion that things should be fixed instead of bypassed, but it seems like this is one of the components that is going to continually break so it's nice to have the option. I'm actually going to send my STVA to you in the near future to get it fixed, but leaving it broken motivates me to finish up this device.
Eventually, though, I think the community will need something like this bypass.
It's interesting to learn that the method for the older bikes turned into the Servo Buddy. I saw that thread a while back and it's actually one of the reasons I started on this project. I was looking for it recently but I couldn't find any copies of it anywhere. It's kind of a shame really, to remove knowledge from the community for profit. It gave me enough basic information to get started with this one, and without it I don't think I could have accomplished this.
So on that note, despite the fact that I could probably make some decent money from withholding this info, I think it's better to share it. Of course I have goals in life that require money to accomplish, but in this case I think it's better to post the info. There's a lot of secrecy around car and motorcycle electronics, and that makes it extraordinarily difficult for people such as myself to accomplish anything. Plus, I've learned a ton of info about the mechanical side of things from people on here and other forums, and it just feels like giving this info about the electronics to the community is the right thing to do. Besides, it's not a 100% reliable circuit right now, and even if it were, I've found (from other forums) the vast majority of people would opt to buy an assembled device instead of undertake building one on their own. I am thinking of potentially manufacturing these once they are reliable so if I go that route there's still money to be made, and hopefully people would choose to support me over the inevitable Chinese copies.
You're completely right about the size. I don't know if much can be done about the size of the inductors, but the circuitboard can be shrunk down to about the size of a penny. I used the very DIY-ish method of a sharpie, pool acid, and hydrogen peroxide to etch the circuit board. I made it large enough that I could swap out components if need be (and a good thing too!) and it is single sided for simplicity so it was intentionally a fair bit larger than necessary.
If you're interested in getting an oscilloscope but don't want to break the bank, the Hantek DSO5102 isn't a bad way to go. That's what I have. The price is reasonable and it can be DIY modified to function the same as the DSO5202.