http://www.jcsbanks.btinternet.co.uk...controller.htm

Tell me what you think. Then I need to get the board made and put this into proper basic and try it.

I don't know what size of overshoot I will get and how flat the held boost will be. I may have to convert to a map with RPM and duty cycles.

 

John, if you get this project up and running I would love one!

Cube.

 

John,

Working in the electronics industry I have access to a lot of PIC documentation, programming and test facilities. I also can help with PCB generation + fabrication and debugging of the complete board.

I am not a PIC expert myself (mainly analogue + a bit of digital) but we have a few experts on-site who I could get answers on particular problems.

I also have no idea on the input and output signals you intend to process, where is this information going to come from?

Automotive electronics is a very demanding environment - you may need to consider transient protection on all your I/O to stop the PIC being damaged.

If you need any help regarding the above drop me a mail at my work address:

richard.curtis@gyrus.co.uk

Rich

 

Thanks guys. I am taking sensor output data from the Link ECU manual which has done me well so far.

It is easy to tap into the MAP and TPS (they are both in the range 0-5V and can easily be read by a high impedance ADC input such as that on a PIC). I have never done RPM, but understand it is just a pulse train - I'll again find a high impedance device to read this.

To start with I may only need the MAP sensor and I will ignore the RPM and TPS to see the best method of getting tight boost control.

My only output will be a solenoid. If I take over the factory one I will need to put a dummy resistor across the original wires from the ECU to fool it that it is still present to prevent a check engine light. This is straightforward. I would however, rather source a solenoid to use separately.

 

I don't know if Impreza2LT (Colin) still frequents this board, but he did a similar project. Take a look at http://www.force8.demon.co.uk/impreza/bcontrol.htm. I've been in his car with his controller running and it certainly made a difference.

I'm just about to start developing for work using the AT90S/LS4433 and have used the 2313 and 85xx series before.

Good luck. If I can help in anyway let me know. Unfortunately I moved from Scooby ownership sometime ago so cant do any 'hands on' stuff.

 

v.0.1 is up on the site and is running P and D. No integration as I don't think it will be useful.

Have a look if you can make any sense of my code.

Thanks for comments/help so far. Progress is good - I only wrote the first line of code 30 hours ago and I have slept and gone to work as well as eaten and spoken in depth to the wife

 

Have ordered this board with a cable, and a higher spec chip and crystal than the one it comes with (so have 2 chips and 2 crystals) all for under £50 inc. postage from Australia. Note the board contains voltage regulator, RS232 driver, programmable LEDs and switches, as well as a headers (like first picture not second) for attaching other boards.

I am going to use the Subaru solenoid - I can get another for £40 if I blow it up - and you would have to be a real monkey to blow up a solenoid

Will use op amp to avoid loading the MAP sensor output. Still to work out the solenoid driver stage - may use a driver IC with integral diodes.

Initial test will ignore TPS and RPM as virtually all the aftermarket EBCs do except Blitz and Apexi. These will be added later if I get the simple one to work!

 

This could be built on a small daughter board to attach to the board above for development.

 

John,

For the solenoid driver try the MICREL MIC4422,

its a high current mosfet driver, will deliver 9A peak from a 12V supply!, is good for >500Khz, has hysteresis and takes a logic input. You may need to protect the driver with a flyback diode across the solenoid if one is not already fitted. A UF4001 should do the job.

If you find the driver getting warm just chuck a low 'RDS ON' mosfet of the output to do the switching, e.g. BUZ11.

If you want I can send u a few drivers in the post, mail me at work if required.

Rich

 

John,

Will be *very* interested if you get it all sorted.

Cheers



Iain

 

I emailed Colin but no reply. The 4433 seems a very capable chip. At least as fast as the old Amiga I used to have, but with less memory, but I don't have to display windows/graphics or make sound.

I have a few ideas for a V0.1 which may have a fudge factor prediction system as it approaches target boost as Stephen Done suggested. Can't do the full PID thing my head will break.

[Edited by john banks - 1/7/2002 1:46:55 PM]