A digital governor for model engines

[gary.a.ayres]

Aha - I wondered what you had been up to!

That looks very smart indeed...

gary

[MJM460]

Thanks Gary, it’s really nice to call it done with a successful outcome.  It was quite rewarding despite the frustration at the last step, but if it was too easy, it would not be so worth doing, would it?

However, I am looking forward to moving on to a more conventional engine project. 

MJM460

[gary.a.ayres]

I look forward to it.

 

[Admiral_dk]

Well done MJM 

Even us Pros do get it wrong from time to time .... and that is almost always the case when one starts to assume instead of measuring or worse using a bad Scope Probe and believing the (wrong) measurement result => doing the wrong deduction. This usually happens with a known good probe that suddenly fails in a non-obvious way   

The other comment is about the MCU you have chosen, as it is part of a very big family - why not chose another one with the required amount off Timers ?
That said - it's not uncommon that one has to do with the one in stock - so you found a way to overcome the limitations 

[MJM460]

Thanks Admiral.  I am pleased that I persisted and got there, and found a definite problem, so I have confidence that it is a real solution.  Much more satisfactory than trying something that finally works but not being sure why.

The limitation on my choice of processor comes down to my ability to program it.  It is a very accessible system, intended for students and beginners.  There are bigger chips in the system, which offer more i/o but apparently more timers.  Certainly there is an application note for a PID implementation on the base PIC chips, but I can barely understand how it works, let alone how to adapt it to the Picaxe system, and I don’t have the ability or equipment to program it on a raw chip.  Basic language with a three pin plug in circuit is about my limit in the programming area.

I think that the timer availability might have been part of the reason it was recommended by another forum member to use a different processor very early in the project.  I saw the possibility in the simple processor, and was interested to see if I could make it work, and while more i/o would have been useful, it was not necessary in the end.

However, I also learned something about that little photo interrupter component and got plenty of soldering practice, along with a new iron after my old one died early in the project.  So it’s all good.

Thanks for your encouragement.

MJM460

[Zephyrin]

so I have confidence that it is a real solution.  Much more satisfactory than trying something that finally works but not being sure why.

You must be happy with such a nice result, congratulations!

[MJM460]

Thanks Zephyrin.  It has been quite interesting.

Now that I can hold the speed constant, I will have to push making a suitable load device up the list, so I can do some engine tests.

So many projects, yet even in lockdown, so little time.

MJM460