hi
i am trying to make a simulation of the sensors of electronic fuel injection system engine. the value of the sensor will be fed to the ECU via keyboard on the computer and i am using AVR atmega 8535 for the serial interface. the problem is there are too many sensors including simple potentiometer outputs and also square waveform generators like crankshaft sensors. i am not sure how to control the outputs of these all sensors with my controller. the options i know of are PWM and DAC but both require massive effort. what can be the most efficient way of controlling all these sensors.
and if i have to use more than one controller would that be adviseable.is there any other way i can do all this.
thank u for ur help

 

when you say 'controlling' sensors, I assume you mean emmulating them. In an automotive system, there are relatively few sensors, and they fall into digital or analog. some of the analog sensors may also be modulated.

You will simply have to take each device and analize it's ouput, over it's operational range, and decide on the apporpriate means to replicate that. You may be short on timers, and certainly will need DACs, or digital pots. Look into I2C pots as a usefull device.

 

The nice part about the "massive" effort is that the uC does not know any better, and will tirelessly give that level of effort for as long as called for.

I suspect that organizing the sensors will show that it's not so overwhelming to account for the various inputs.

 

thanks for the reply
D-pots really like them and thinking of using them (thanks)
the outputs of the sensors have been checked and i can run the engine fine while giving output via a potentiometer for a throttle position sensor
and also i have emulated the crankshaft position sensor using stepper motor speed variation

but the real problem comes for me when i am dealing with this problem digitally
i am using two ports partially or entirely for serial interface to the computer and timers for emulation of crankshaft and camshaft sensor. rest two ports can be utilized for the DAC or D-pots but that might require multiplexing as there are too many sensors
also i thought of PWM for every sensor with a single pin of MC in use but that also accounts for very complicated software effort
so i wanted advise on the design phase for what should i be using
and if there is any other option available then what could that be
thanks

 

Is there a description of these ecu signals described somewhere?

 

yes mmclaren i have a manual of the 2nz-fe engine of toyota
and all the description of the inputs to the ecu and from the ecu are given for a technician to measure
so i got it from there

guys what is a multichannel D/A converter any link might be useful
thanks