[Rallyfinnen]

Newbie here so have patience.. Played around with Megasquirt ages ago, but memory has faded

I plan to run a simple servo control vs RPM for power valve control on an old Yamaha DT125 single cylinder two stroke engine. Possibly ignition too if I can get the power valve working first. Servo is a standard RC servo, and the plan is to use the VVT output for this (D4?). Hall input, and PWM output to servo. This is so simple, so I don't plan to use the Speeduino interface board, but just an Arduino 'proto board' with a few components for the signal conditioning.

I got my Arduino Mega today, and connected it up, installed the Arduino firmware, installed tuner studio, and got it up and running. I wanted to check the basic function using a square wave crank signal from my function generator to see the RPM on the dashboard, connect up the servo and play around with it a bit. I set the trigger to simple distributor, single cylinder two stroke. Fed 5V square wave on pin19 (on the Arduino) and fired it up, but no luck.. I'm thinking I should get an RPM reading like this?
I also tried pin 18, since I'm not sure which one is used for distributor input.

Suggestions?

[digmorepaka]

Fed 5V square wave on pin19 (on the Arduino) and fired it up, but no luck.. I'm thinking I should get an RPM reading like this?
I also tried pin 18, since I'm not sure which one is used for distributor input.

Suggestions?

Most hall sensors don't have a pullup fitted. You need one. Basic distributor setting uses the primary(crank) input for your board layout. If you just use the bare mega you're asking for trouble. No protection circuits and missing supporting circuits for sensors and outputs.

[Rallyfinnen]

Ok, thank you for the input!
I intend to add some protection features before I connect it to the 'real world', but in this case I was on the bench using 5V square wave from the function generator and got no RPM reading. Scope was showing 0-5V square, so in that case no resistor should be needed?
Are the arduino boards super sensitive? Could I have blown the input with just some static or similar? That would be annoying.. Is there some easy way to see if the input is still working? Could I be missing something else?

[digmorepaka]

I was on the bench using 5V square wave from the function generator and got no RPM reading. Scope was showing 0-5V square, so in that case no resistor should be needed?

Ah sorry, wasn't entirely clear to me if you were using a bench setup with a real sensor or the function generator when you were having issues. What you're describing should work fine. First make sure that you are using the correct input pin for the selected board layout as there are several, and that you loaded the base tune before changing your settings to what you need them to be.

[Rallyfinnen]

Thank you for the tip!

I made a step forward by starting from the base tune. Had some error messages when loading it, but after setting it to distributor trigger, I got RPM!

Now I'm stuck with the VVT PWM. I set it to open loop PWM and made a table for it, but it seems to do nothing. According to the table it should output a few %, but looking at the gauge it reads 0% (see screenshot). I don't see anything on pin4 on the scope either. Makes me think there is a 'blocker' in the software? Is the VVT PWM output disabled with distributor trigger or something like that, or what could it be? Sorry, I'm pretty clueless when it comes to code..

Alternative approach:
Is there another output I cold try where I could map PWM duty vs RPM with constant PWM frequency around 50Hz? Load is not really needed for the power valve control.

[digmorepaka]

Now I'm stuck with the VVT PWM. I set it to open loop PWM and made a table for it, but it seems to do nothing. According to the table it should output a few %, but looking at the gauge it reads 0% (see screenshot). I don't see anything on pin4 on the scope either. Makes me think there is a 'blocker' in the software? Is the VVT PWM output disabled with distributor trigger or something like that, or what could it be? Sorry, I'm pretty clueless when it comes to code..

No way to tell you without a log and tune. Could be a number of things.

[Rallyfinnen]

Not sure how to supply that.. I guess the tune is the tune-file, should I create some kind of log in tuner studio with it running as complement? Upload as attachment here?

Thank you for supporting!

[digmorepaka]

Not sure how to supply that.. I guess the tune is the tune-file, should I create some kind of log in tuner studio with it running as complement? Upload as attachment here?

Thank you for supporting!

File -> Save Tune As -> path to export

Ctrl+L to start log Ctrl+K to end log

upload as attachment in a reply

[Rallyfinnen]

Thanks!

Second try, I uploaded some files before, but the tune/config had the wrong VVT settings from when I was playing around with it so I went back to the open loop PWM and did another log. This time I have RPM from just picking up EMI on the crank input, but it thinks it has 3k as RPM, so it should PWM the VVT.

The only obvious 'blocker' I can see is the coolant temp, but with it set at -40, and the open input reading +200, I think there is a safe temp margin

[digmorepaka]

Thanks!

Second try, I uploaded some files before, but the tune/config had the wrong VVT settings from when I was playing around with it so I went back to the open loop PWM and did another log. This time I have RPM from just picking up EMI on the crank input, but it thinks it has 3k as RPM, so it should PWM the VVT.

The only obvious 'blocker' I can see is the coolant temp, but with it set at -40, and the open input reading +200, I think there is a safe temp margin

Log is empty, but it probably is the coolant temp. Flashed your tune to a test bench and VVT output works fine.