For discussion of Speeduino compatible boards designed / built by other members of the forum and for guidance around making such a board
By bugster_de
#43211
Hi folks,

I'm in the middle of designing my Speeduino for my Volkswagen Campervan and have a question regarding unsued sensor inputs. I will not connect all sensors (e.g. TPS) as the engine simply doesn't have them mechanically. Would you recommend to set the respective input pin to some defined level? If so, which level? GND, 5V or e.g. 2,5 volts via some voltage divider? I'd like to avoid having those signals hopping around and eventually causing strange effects in the software, that I end up chasing forever. My uneducated gutt feeling tells me, that a voltage divider (e.g. 2 10kOhm resistors) supplied by 5V is the way forward.
Sensors affected: TPS, RPM2 (Cam-Signal), Knock, Flexfuel, Launch/Clutch.
And can I connect them all together? So have e.g. one voltage divider and connect that line to alle the pins?

Thank you so much
By LPG2CV
#43212
Other than the TPS, the sensors you list, you do not need to do anything with them, as you turn them on/off within Tunerstudio.

TPS is required for acceleration enrichment (AE). Unless that can be done with map, as I've not kept up with development. :)

TPS sensor does not have to be at throttle body. It could be at the pedal.
User avatar
By PSIG
#43217
I specifically "tie" unused timing inputs high or low. As some trigger decoders are constantly "looking" for a second input (e.g., Missing Tooth) even if it's not there; noise can trigger a cycle signal unintentionally. Other than that, the functions can generally be disabled, ignored, or flat-lined (zero response).
By jonbill
#43221
PSIG wrote:
Thu May 28, 2020 3:19 pm
I specifically "tie" unused timing inputs high or low. As some trigger decoders are constantly "looking" for a second input (e.g., Missing Tooth) even if it's not there; noise can trigger a cycle signal unintentionally. Other than that, the functions can generally be disabled, ignored, or flat-lined (zero response).
David - beginner question - how do you do that ("tie" the input high or low)? does it just mean connect it to ground or 5v?
By noisymime
#43228
I would generally recommend connecting (aka 'tie-ing') unused things to ground, HOWEVER it's probably only needed on the TPS and RPM2 signal. All the others will be ignored when the relevant option for them is turned off in the tune. If the option is turned off, the system won't even attempt to perform a sensor read and will just default to 0 values.
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