Any general discussion around the firmware, what is does, how it does it etc.
By cano507s
I'm new here, and new with speeduino.

I was reviewing the code and noticed that the reading of CLT and IAT is done through analogRead, and looking through my local electronic store I noticed that there are single-wire digital temperature sensors, these can be coupled to a single digital pin, it occurred to me that could be used as an exclusive speeduino EGT control, I don't know if other ECU brands use this technology, but it would seem great to me... I read your opinions
By Alfagta

i have never seen 1 wire sensors in automotive.

Which sensor have you in mind to read egt? I have never seen sensors with measurement range higher than ~150 degree.
By JHolland
Are you referring to one-wire or 1-wire sensors? like the old Dallas/Maxim (now Analog Devices) devices?
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By digmorepaka
The "1-wire" sensors the wiki refers to are NTC/PTC sensors which are grounded against the casing and only have one signal wire. These are used for instrument clusters. There are also thermal *switches* that can be had in this arrangement, often used for an overheat light, or as an e-fan thermostat when ECU does not control it.

Due to the less than ideal ground loop these have, they are unsuitable for an ECU.

What your electronics store likely has is something to the effect of DS18B20 which is a one wire digital link. This particular example is not automotive rated first off, and second not something that speeduino supports by default.

For your engine you want a standard automotive rated sensor with a casing independent of the sensor inside, and an NTC with both of it's terminals wired to the connector.

For EGT you want to use a thermocouple such as a K-type, that needs an external amplifier to turn it's low voltage low current signal into something usable. Speeduino doesn't have EGT control at the moment as it's not something that is very important on a benziner.
By cano507s
The max31855 supports thermocouples in 1-wire configuration, these are not for automotive applications, but it does not mean that they cannot be used (90% of the components of my speeduino are not automotive and work perfectly).

Regarding the software support for speeduino, yes I understand that it does not support it, that is why I consult with you... I can program the code to read the signals from the sensors, but I still do not know how to integrate them into the speeduino code (not I'm a programmer, I'm a mechanic).

The function of this would only be to record data to the datalog or display it in real time, to be able to make adjustments based on the data obtained.
By JHolland
cano507s wrote: Wed May 22, 2024 1:19 pm The max31855 supports thermocouples in 1-wire configuration
I had a quick look at the data sheet and a shows an IC that interfaces to a standard 2-wire thermo-couple with a 3-wire SPI link to a micro.
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1. What specific advantage are you seeking with 1-wire or one-wire sensors?

Options are always appreciated, and while "better" has many perspectives, we tend to only apply things that have a clear advantage over existing methods. In order to gain support for other options that have known concerns or issues, advantages must be substantial in-favor of it. I'm open to ideas. Convince us. ;)
By cano507s
The idea is to be able to have EGT available for each cylinder, without having to use many pins on the Arduino. In brands like FuelTech, independent controllers are used that communicate via CAN and I consider that it would be an advantage to be able to use it without the need for the independent module (as in emtron or other high-end ECUs)
By cano507s
JHolland wrote: Wed May 22, 2024 1:30 pm
cano507s wrote: Wed May 22, 2024 1:19 pm The max31855 supports thermocouples in 1-wire configuration
I had a quick look at the data sheet and a shows an IC that interfaces to a standard 2-wire thermo-couple with a 3-wire SPI link to a micro.
Sorry, my mistake when writing, I was referring to the max31850k, this method to be specific, and it is just one example of several that I found ... -MAX31850K
By JHolland
The details for that website refer to 'any microcontroller that supports 1-wire' - they all do, you can bit-bang the protocol from any digital I/O pin. there are a few app notes about that have example code. The only aspect that might seem a bit unusual is the need to implement an open-drain/open-collector interface. This is best done using a transistor circuit to isolate the micro from any noise or spikes that are picked up on the wiring, that will mean that you need to invert the logic or use two transistors. The alternative method is to set the micro-pin low and toggle between input and output to drive the line, if the 1-wire interface is going off board then that is not a very idea.
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