Looking at main unit first, how many inputs are required of each type ? 0-5V, temperature, digital pulse.
What sensors, and what combinations would people envisage ?
Typical install I would think.
Analogue sensors.
Bosch standard thermistor:
Coolant temperature.
Intake temperature.
Oil temperature. (Are Bosch standard thermistors normally used for this ?)
Outside temperature.
0-12V (if connected to standard dash) or 0-5V (inputs can be universal 0-12 with reduced resolution at 0-5)
Fuel gauge.
MAP sensor (boost pressure)
AFR (Wideband output 0-5V)
Oil pressure.
Fuel pressure.
Other (special)
EGT (Type K thermocouple)
Digital sensors (0-12V pulse, threshold at about 2V)
Built in.
Battery voltage.
G sensor (x,y,z). Would require box to be mounted horizontal for accurate reading.
So that's 10 external plus 1 internal analouge input.
2 external digital inputs.
Currently looking at a choice of 2 processors. Both support canbus and have 40 pins.
dsPIC30F4013 - has 12 bit a-d x 13 inputs but is a bit short of I/O as processor has loads of power pins.
PIC18F4682 - 10 bit a/d x 11 but has 5 more i/o pins overall.
(10 bit = 0.1% resolution, 12 bit = 0.025% resolution) e.g. 0-12V in steps of 0.012 or 0.003
Another possibility is use the dspic and a separate processor just to drive the display linked via I2C. May work out well as the display will probably be on a separate PCB anyway
So on the face of it, we have 2 spare analogue inputs (and maybe more digital). What are peoples thoughts about how many should be temperature, and how many should be 0-12V (0-5V)
Do people think there should be more than 2 digital inputs, if so what sensors ?
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