hi guy !
First, a little introduction : i am a software engineer, working on airplane and helicopter calculators. I have some knowledge on programming embedded critical and real time apps. But i have little knowledge on MCUs, as our calculators are alwayw using huge µprocessors, so i dont know if the primer 2 will be able to do this. Also i am french, so please forgive my spelling, or if i sound aggressive, i will try not to.
I am also a car enthusiast, using it on track, and have now quite a lot of gauges, to the point they are useless as i cant see them all the time. So i am planing to do an automotive gadget application which will do everything these do, on a single unit, with a single screen, and a little extra: data logging, not just displaying.
It will have to log values from speed sensor, oil temp and pressure sensor, water temp sensor, and air/fuel ratio sensor. All these sensors are analog (i can get the AFR & speed already processed from serial, but i would prefer to get them directly). These sensors, apart from AFR and speed, are variable resistor types. Speed sensor is a sinusoïdal wave varying from -3v to +3v, AFR is a linear signal varying from -5v to +5v.
So i need at least 7 analog inputs (1 for Vref, 1 for ground, best way i found to get stable values in a harsh environment), and i guess i will also need a way to lower the voltage from the AFR sensor. But do i need to provide power to the variable resistors ? It looks like my current setup does not (the sensors are connected to the ground, and there is only 1 wire coming out of them, getting right in the gauge). Sorry if this is basic knowledge, i lack hardware design knowledge (this is why i want to use an integrated board).
it will log the values on the SD card and/or stream them to USB.
it will show the values on the LCD, and each of them will have lower and higher alarms.
It will also have to output a sinusoïdal wave signal (with almost no power, just a slightly altered copy of the speed signal. The goal of this is to remove the speed limiter. I am using the car on a track and hit the speed limiter on a straight. the simplest way to cut it is to stop the signal from going higher than a given frequency, as i cant modify the car ECU to get rid of this).
i dont know if i will use the touchpad. i WILL need to create a configuration screen to set lower and higher threshold alarms, but i find buttons to be easier to use. so this is a "maybe".
I need to acquire speed, oil pressure and AFR as fast as possible, as a failure on one of them can occur fast and leads to killing the engine. The temp sensors needs to be accurate to +/-2°C, and 2 acquisitions per second is fast enough for them.
I plan to add the 3 other following features, depending on the power available on the MCU : 2 of them require solenoid control :
-1 will need to be very fast and accurate ( turbo pressure control, by opening and closing a bleeding valve)
-1 will not ( function called turbo timer : it allows the car to idle without the keys on it until temps have gone low or a gear is engaged, then cuts the ignition).
last one will require quite a lot of power and an external 5Hz gps. I saw it has G-sensors; coupling G-sensor with 5Hz GPS tracking allows me to log my exact trajectory and the forces the car takes on the track. I know how to code and use the tracking, as i have already done one. This would be a great tool, but i wont be using it right away;i am still lacking driving skills to have benefits from this. But if it has the power to do it, that would be great.
I read that the primer 2 has 2 ADC inputs, and i can use 16 channels on each of them. How ? are the pins available somewhere on the board ? Do i just need to set the GPIOs to use them, or do i have to use a mux ?
If you think it has enough power is hardware capable, to do the first functions, i think i will get one, it looks nice and is not that pricey 
