Modern Vespa

Hi all

A slightly left of field question but here goes ...

I've recently fitted a universal fuel sensor from LSK Electrics - basically it's a pressure transducer and convertor that measures the head pressure in the fuel line and converts to a signal for a fuel gauge.

https://www.lskelectronics.com/store/FuelGaugePro-Universal-Sending-Unit-kit-p286978985

I'm wanting to keep the instrumentation as minimal as possible so thinking of getting the SIP Speedo 2.0 as would like the CHT temp etc as well.

However as these don't display fuel level (for a Rally 200) was thinking I might be able to use the RPM display instead.

Just thought I'd check if anyone could clarify what the actual signal type used by the tacho and if I could convert the fuel level signal?

I suspect the rpm signal might be a voltage and the fuel level is a resistance. If so ideally at 100% fuel the tachno would display say 10,000, then for 50% 5000?

Any suggestions about how I might get this to work would be terrific.

My scooter is setup with 12V dc.

Thanks so much

- Matt

I've looked into this more and found that the input signal from the fuel sender is a 0 - 12V PWM signal and the rpm readout needs a voltage frequency reading.

It seems it should be somewhat straightforward to do with an arduino etc, though pretty much have no idea how to approach this.

Any suggestions would be fantastic.

Cheers!

I'm sure this is possible with an arduino, but will need some work to code and test. It might also need some supporting components, because I believe Arduino runs 5V.

Depending on the specifics, it might be easier to find a dedicated device.

I originally thought you'd need a pwm digital to analog voltage, which shouldn't be too hard to find. Like this (10V version): https://opencircuit.shop/product/pwm-to-analog-0-10v-converter-module

But you mentioned voltage frequency. So I'm not certain what that means in this context, but I guess it's more than simple analog voltage. Maybe pulse counting, or something.

Anyways, just thought I'd put out the idea that you might be able to get an off the shelf converter reasonably easily.

I must say I am a little surprised you'd want a fuel level more than tach on an NSM bike.