[Mouch]

Hello Guys,

Just starting to find out the potential from this ECU.
It has been very good with the standard assembled board (v.04.4d)

But now I am trying to connect more sensors to the board.
I want to use AN12-14 for 2 temperature sensors and 1 knock senor.

I've got it al soldered up and communicating with Tunerstudio, but now how to config the 0-5v signal.

I've got all my resistances from 3 points (-18/20/100 degrees) and if I am correct the maximum amp from the 5v on the mega is 40 mA.

Tried to calculate it back to voltage but somehow I can't get it to function.
Whenever I put the 5v on, it directly goes to max which is good.
But when I put the sensor in between it reads 1.7v over the sensor but still goes to max on the gauge?

What am I missing here?

Any help would be awesome!

[LPG2CV]

Does the attached help. Take a look at IAT/CLT sensors.
What you are probably aiming for is a voltage divider.

[Mouch]

Thanks!

If I understand correctly in the schematics you have to built a small circuit to make the sensor work?
Is this correct?

I thought it was possible to attach the sensor direct to the analog port, my bad....

[Mouch]

If I understand correctly I have to build a small pcb.... It says ADC clamp in the schematics, where can I find this on the Mega 2560?

[Kalns]

There is an IC called ADC clamp, I might be wrong about this, but if i am not then its just a resistor for pull-up or pull-down.

[dazq]

There is an IC called ADC clamp, I might be wrong about this, but if i am not then its just a resistor for pull-up or pull-down.

No the ADC clamp is NOT just resistors.
It contains a couple of diodes ( and a few other bits) ,its purpose is to redirect current to supply rails if a fault occurs.

If you look at an earlier schematic of v04 you will see how to make the same circuit but using discrete components instead of the clamp IC.
Below is what the clamp IC part of the schematic is and what a fully discrete CLT input circuit is.

[LPG2CV]

First of all, I'm not an expert.

The adc clamp refered to in the schematic, is an ic that provides over voltage protection to the various inputs on the board. It's an array of diodes. Look in the schematic for the SP720. If you look at the clamp #, you notice it differs from that of the iat or the other inputs to the ic. The ic inputs have all been used I suspect. Though basically, it's just a pair of diodes per input.

I havn't been able to locate a shematic for your particular board, so assume it has not been released yet.

If you go to the following link, you can click on the big green button, and download the zip for the official released versions of hardware. https://github.com/speeduino/Hardware

Have a rummage through and find Speeduino v0.3.2_schematic.png to see how individual diodes were used rather than the ic.

LIkewise, the firmware side of it, is available here. https://github.com/noisymime/speeduino

And, if you havn't red it yet, the Wiki is here. https://wiki.speeduino.com/en/home

On a final note, you may be able to connect and display the sensors, but knock is still in developement.

[Mouch]

Ok, I think I understand....

Is there a difference in design (advantages) of building one with a ADC?

Or will the V04 suffice? If I understand correctly you can build this one without ADC, right?

[Mouch]

I have a knock sensor which delivers a 0-5v output (Phormula KS-4)

I think this one doesn't need any additional PCB...

Thanks for advices all of you!

[LPG2CV]

I forget how many exactly, but the ic has I think seven inputs. So perhaps just a pair of diodes then.

I don't have access to the board you have, but it's not impossible that something has been built in.

Though you really don't want to add inputs without protection. The engine bay is a hostile environment as far as emi goes.

The circuit would probably work without the protection, and without the capacitors even. But how well, and for how long, is a different matter.

The protection is not protecting that circuit, its protecting the rest of the board from overload on that circuit.