Chiped....

[bearda]

Originally Posted by markitect

I've been thinking about this:

The accelerator position sensor just has two output voltages.
So my guess is the Blitz/sprint controller is just a simple microcontroller with two analog inputs and two analog outputs, or even simply a rom with a table mapping the input to output and the switch changes an address base. There Might be RMS converters too.

Takes the voltages in, puts them into an equation and outputs the result on the outputs. Add a couple GPIO for the reverse sensing and mode switching, and something for the display.

That said you could use an oscilloscope to see the factory signal as the pedal moves, then come up with a desired signal over the range. Then find a mapping between the two.

You could then get an appropriate microcontroller and build your own.
Possibly design a analog circuit that will perform exactly one mapping.
Or have a rom with a lookup table with the analog inputs addressing it and the value in each address corresponds to the output at that input voltage.(This seem easiest, but someone that programs PIC microcontrollers will probably opt for number 1)

I was messing around with doing something similar for my Mazda. I'd started on one design based on a signal ADC/DAC when I found out there were two APS signals and that they had to correlate. If anybody knows of a good cheap microcontroller with a built in two-channel 5V ADC and DAC maybe I'd get it started back up.

My plan was to hold the table in EEPROM and make it configurable over the serial port.

[marcus]

Originally Posted by bearda

I was messing around with doing something similar for my Mazda. I'd started on one design based on a signal ADC/DAC when I found out there were two APS signals and that they had to correlate. If anybody knows of a good cheap microcontroller with a built in two-channel 5V ADC and DAC maybe I'd get it started back up.

My plan was to hold the table in EEPROM and make it configurable over the serial port.

hope you do start it again..cant wait

[CTScott]

Originally Posted by bearda

I was messing around with doing something similar for my Mazda. I'd started on one design based on a signal ADC/DAC when I found out there were two APS signals and that they had to correlate. If anybody knows of a good cheap microcontroller with a built in two-channel 5V ADC and DAC maybe I'd get it started back up.

My plan was to hold the table in EEPROM and make it configurable over the serial port.

I use PIC microcontrollers for everything - They're cheap and there are many options for I/O configurations (analog and digital). The DSPIC series have DACs, but I would actually go with a non-DSP one and use I2C DACs like the Microchip TC1321, that way you can chain as many as you need (up to 255 of them). I would really like to have a spare Yaris to experiment with (a wrecked one with a running engine would be fine).