Gear Position Indicator for Triumph Sprint GT


New Member
The GPI project is running in VSM at last and I have to say the is the best sim I have used to date.

View attachment GPI v1.DSNView attachment GPI v1.bas

I would appreciate any feedback as I now want to move to the actual loading of the chip

I have a cct for filtering the speedo and tacho inputs and can upload them if anyone is interested.
When I used the input filtering ccts in VSM it slowed the simulator down too much

I have to get my Oscilloscope and have a look at the actual waveforms from the Motor Cycle outputs (Speed, Tach) to see how many pulses I get on the Speedo feed for a given speed. And to check the duration and size of the tach pulses. Got a bit of a brain ache there in that I am sampling one of three direct fire coils (3 cylinder engine) and don't know if I have to divide by three or not.

Anyone got an idea how I could simulate real time variable frequency inputs (say with pots) for the Speedo Tacho instead of what I have now on the VSM?
That way I could run the tacho and the speedo up and down to verify the 7 Segment ouput in real time

Thanks guys


New Member
I now have a Sim for the Tacho. I am using the Signal generator for the pulses.
This works well as I can adjust the Signal Gen (Tacho) in real time and observe the GPI indicating the change in gears.
I can stop and manually adjust the speed pulses.

I am going to take this to the main forum now as I am having a problem with the sharp cut off when the ratio is changing.
The display flashes from one gear to the next on crossing point and I need a way to soften the change.
Is it hysteresis that I am looking for.
Anyway I am after a fix for the code to soften the change.

Any ideas?


New Member
View attachment GPI v2.DSN
Simulation now has variable speedo and tacho inputs. should have went this way at first. all works very well and output to the display corresponds with the spreadsheet figures for my bike. I have added a input for the clutch lever switch that will show a "N" "n" while gear changing. If I change without the clutch there may be some display bouncing on gear transition but I can live with that for now.

I will put a copy of this on the main forum as I would like to know if I am able to use a smaller pic and still have all of the features on this project?