nothing is stacked weird on the one jason made for me. it's about 3/4 x 1" total size. not bad.

I meant the warning light circuit.

Thx, I'm working on a how-to. It's up on my Westfield site but I'm only halfway done. I'll post it here when it finished. As I have no access to the car right now it might take a month or 2 though.

Jason's is perfect, it's just that I'm trying to install all circuits (alternator, CKP & CMP, EBC, Fans, Vics and WI) on the MS board and often that means stacking components in an unusual way. Not so here :).

I'd have room in mine as well for that, though there's a bit of weird stacking. If I had it to do over, I'd leave off the EBC, which sucks horrifically. Maybe the new PID code on MS-II works, haven't tried it yet, if it did, EBC would be a nice thing to have. Certainly can't complain about spool on my ball-and-spring, though. I don't remember where, but I put mine on the heat sink, replacing some unused thing, threaded it into some of the circuitry at the DB-37 end of the board. Even the trace sizes made sense.

Here's the 12.8V threshold warning light.

edit: a 0.1uF or 0.22 uF cap between top and middle terminals of TL431 is necessary to make the warning light act digitally"

cool, thx

Here's the proto circuit with
- 2 programmable outputs for fans and vics
- knock input for knocksenseMS
- alternator field
- 2 active low inputs for launch control and table switching. Altough the manual says otherwise, JS7/PE0 is for launch control. R1/PE1 is for table switching! You need to free up 2 additional spare ports on the processor if you want to use these options.

There's not enough spare pins on the DB37 for all circuits, so I added an old chassis mount keyboard connector. I labeled the active low inputs AL1 and AL2.

There's not enough room for a 2N2222A (metal can) so use PN2222A (plastic) or ZTX450 instead. These are direct swaps.


http://westfieldmx5.devocht.com/star...lternator1.png

What are y ou using for a knock sensing circuit, where'd you get it from?

I haven't actually decided. I think I'm gonna use the MS circuit with the oem '99 sensor. I have access to a Link Map sensor (with built in knock circuit), so I might reverse engineer that at some point. If all that fails, I can always get KnocksenseMS, but I'm not convinced it's better though.

I have yet another schematic, for a knock sensor amplifier that works with the factory 99/00 knock sensor, and is tuned for the miata knock frequency...

You never fail to amaze me. I'm sure you know what my next question will be :).

I guess my question will be the same as Frank's...

where, how, how much....

can it be used with a parallel install so the stock ECU and whatever else can both see the signal?

With some mods yes.
The circuit is meant to emulate a GM style tuned piezo knock sensor.
IOW you take a 99/00 knock sensor, it filters and amplifies the signal. It is tuned to 13 khz IIRC, which is the peak frequency that I noticed when I did recordings of knock.

Started a new thread in ECU's.

Just found out that I forgot the circuit for the tach out in the circuit above.
Made a new one with tacho out.This one is using JS11 for tach out. It comes out on IAC2A on the DB37.
JS11 was previously used for EBC, but there's just not enough spare outputs to do everything.
FWIW.

http://westfieldmx5.devocht.com/star...lternator2.png

You can change the 3k resistors to 3.3k, and the 30k to 33k.

However the 48.7k needs to remain 48.7k - you can substitute this with a 51k in parallel with 1Meg - but if you use 5% instead of 1% resistors where specified, test that the voltage regulation setpoint is accurate, at 14.1 to 14.4V.

If you do that, you don't bump the 9k to 10?
k?

Also, the ztx690 is a 2 amp NPN - do you need two amps?? Couldn't I just use a 2222A (1 amp)?

What 9k resistor?

Are you looking at the 12.8V warning light circuit or the alternator controller?
The former needs a ZTX690 to drive the warning light because of the heat generated and the gain required, not because of the current.

Jason,

Can I test the alternator circuit out of the car?
I built it, but would like to test on the bench before hooking it up to the car.
When I apply 12V and ground, am I supposed to measure anything on the Field wire?
Increasing power from 12V to 14.4V make a difference?

How to test
 

Place an ammeter between the field output of the circuit to ground.
When the battery voltage is below ~14.2V, the ammeter will see ~13 mA. When the battery voltage is above ~14.3V, the ammeter will see 0.

Jason's circuit never worked for me. I rechecked the pcb I made 100 times and I still couldn't find a glitch. So obviously enough, I did what every geek should do, I made my own PID controller using a microcontroller and a 2x16 LCD. Did I say that it is totally tunable? Pics in the afternoon.

Jim