[Anders]

Hi,
I have connected my Vss signal to the default pin (D2) and filled in the pulses/km in the dialog box.
The car is on axle stands because it cannot be driven at the moment. When i turn the wheels no speed is shown in TS. When I scope pin 2 on the Mega I have a clean square wave and when I test to make pin 2 an aux channel it goes 01010101 when I turn the wheels so the Mega can read it.

- Is there a minimum speed or number of pulses i have to reach before speed is shown in TS? I have tried to set a lower number of pulses/km but no speed indication.

- Is there any setting somewhere I can have missed?

/Anders

[Chris Wolfson]

I don´t think you can turn the wheel fast enough by hand to have a km/h reading.

[Anders]

OK.
But I can turn the wheels 1 turn in about one second. That would be 24 pulses equal to 1.77 meter . 6.3 km/h.

If I reduce the number of pulses/km in the settings by a third it would be 19 km/h but still no speed is indicated in TS.
What is the minimum speed that can be detected then?

[Chris Wolfson]

Why don´t you just infuse a constant signal instead of using wheel sensor? That way you can ply around until it works. Would be pretty exhausting to do that while constantly turning the tire.
If you don´t have a generator: DC from any transformer, with a limiting resistor, gives a nice 50Hz sine wave. If you need more of a square, a Zener diode will cut the sine which will work just like a square for an Hall input.
A sound card should work as a 2v generator too, with some software.

[JHolland]

What type of signal is your VSS signal? Have you scoped it to see if the amplitude is sufficiently high enough to trigger the Speeduino input?
There is usually a minimum frequency requirement for a VSS, related to the timer roll over period, you would need to check the code to see how Speeduino handles this.

[PSIG]

In this thread, he registered VSS down to 1 mph: viewtopic.php?f=15&t=4555&p=49189&#p49175

[Anders]

Thanks for help.
But I have now tried to connect D2 to D3 on the mega and changed Vss-pin in TS to pin3.

Then I get speed indication i TS. Up to 6 km/h by just turning the wheels.

But why does not The board default pin work?? Is the board default really pin 2 (flex )?
I have a 4.3.c board

/Anders

[PSIG]

According to the v0.4.3 schematics, yes, D2 is the Ethanol (Flex-Fuel sensor) input. Note in the image below, it is from J64, and includes a 5V pullup. This is because the ethanol sensor is expected to only ground the 5V pullup with its pulses, creating a 5V-0V signal. If you are sending it a high/low signal, and the pullup is also there, it could cancel the signal to always-high. Could that be your issue?

Spdno D2 Eth input v043.jpg (7.54 KiB) Viewed 3445 times

[Anders]

I had already removed th R61 and when I scope directly on the Mega pin 2 I have a clean 0V-5V square wave.
Also as I did the test to make the pin 2 an Aux input an then I could read 010101010 in TS when the wheel was turned so the signal is clean and can be read by the Mega.

It is just that Vss on pin 2 will not work.

Is flex-fuel a signal requiring interrupt? can it be that attachinterrupt is missing?

The issue for me is solved as I can always use another interrupt pin (I consider 21) or 3 that is working.

But it would be nice to understand why default pin does not work.