Anything not specifically related to the Speeduino hardware. Eg sensors, bluetooth, displays etc
By Kalns

Does anyone know if there is any alternative to MPX4250 map sensor that could be more or less easly implemented into speedy ? I am looking everywhere and cannot find any supplier that has them..
Can I use some generic map sensor from some vehicle and wire it in ?
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You can use any absolute-pressure analog 5V MAP sensor of suitable range, either internal or external. Specifications are needed for custom calibration. There are many choices. Some have used external MAP sensors mounted internally in the Speeduino case with jump-wires, in order to avoid the additional wiring and connections of an external mount. Lots of options. Do your thing.
By Vauhtivaunu
MacAks wrote: Wed Dec 29, 2021 10:12 am MPX5700DP works.
Isn´t that a bit overkill? 7bar absolute pressure? It´ll work in very small voltage range in normal engines. And mouser is out of stock also MPX5700´s

OP: there is few MPX4115AP´s left in mouser if you´r engine is naturally aspirated. Also Finnish shop Partco have one MPX4250´s left: ... 250ap.html in case you need boost capable sensor

At least they send goods in EU zone

Edit: Digikey have MPX4250AP´s in stock: ... wA4gF0BfIA
By dazq
You could also use the 3wire GM type external map sensors, these come in 2,3 and 4 bar variants, and iirc a 5 bar too .
Many of the external map s nsors used in modern diesels use high value units and fit easily into a bung in the charge pipe
By Vauhtivaunu
MacAks wrote: Thu Dec 30, 2021 7:08 am Big turbo engine. 250kPa absolute is about 1,5 bar turbo pressure depend to atmospheric pressure. My turbo blow 1,7-1,8 bar.
There is or was better solution up to 3bar: MPX4400AP. I´d used them lot. It´s better to have resolution in voltage range so there is room for errors in equations. Even You use somewhat whimpy 1,8 bar that MPX5700 sensor only goes like under one volt area. In MPX4400 and 2.4 bar pressure in audi 5-cyl there was plenty of resolution to go even with ancient megasquirt 1. And that helped lot in tuning that engine.

I´d recommend to use MAP sensor that is most suitable in pressure range anyone will need.

Edit: there is still MPXH6300 and MPXH6400 sensors that are 3bar absolute and 4bar absolute as for 2bar/3bar max boost pressure but they are tiny SMT pieces. I soldered them back in days in so called breakout boards until I found MPX4400AP. But it is not available anymore so there is only option for DIY´er s to solder those tiny pieces if one needs board mounted MAP for some reason. Or use GM sensors with wires like mentioned
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From the datasheets, the Honeywell ABPDANV030PGAA5 does not read absolute pressure, as we need? This one only reads atmospheric and higher (gauge/gage, ambient pressure is zero, no vacuum). Hmm… But, it is nice to see Honeywell's lower prices. :)
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