MJLJ Stimulator...with some pics

MartinM · Post by **MartinM** » Fri Jun 01, 2007 10:00 pm

Here's something I knocked up for fun - just connect +12v to the connector near the Molex, the Molex into the MJLJ and the computer to the MJLJ and the rest should be self-explanatory from the picture!

Only components are the LEDs, some series resistors and an Atmel AVR (ATTiny13 - about GBP0.75) with about 75 lines of assembly code....

Post by **brentp** » Sat Jun 02, 2007 6:44 am

Looks neat! I'll post pics of mine, but yours wins in sophistication, I only used a 555 timer to stimulate PIP.

I'm also building a new test bench for more elaborate testing, I'll post pictures of that as well!

MartinM · Post by **MartinM** » Sat Jun 02, 2007 7:07 am

I used software so that I could get the rpm (500-8500) to be linear with the pot rotation - the ATTiny13 has an onboard ADC, so I thought I might as well use it!

It's not really a test bench, since it doesn't take any notice of PIP - that's the MkII version I suppose

It also, obviously, only does Engine Load as TPS - I still have my trusty syringe and windscreen washer pipe for MAP

Post by **brentp** » Sat Jun 02, 2007 7:33 am

No kidding on the non-linearity! the last few 1000 RPMs are a bit touchy!

I've attached pictures of my abomination

it's not pretty but it does the job. The MJLJ unit it's attached to is the grandpappy first MJLJ v2.0.

You know what works great for testing the map sensor? One of those rubber bulbs used for clearing an infant's nose. Cleaned, of course.

Spockie-Tech · Post by **Spockie-Tech** » Wed Jan 02, 2008 1:01 pm

Hi Martin

I relaise this is an old thread, but I have just completed two Megajolt/EDIS's, and am interested in the source code to your driver micro if you will share it.

I have AVR programming facilities, and even a ATTiny on the shelf !, so is you code and a diagram available please ?

regards

Brett

MartinM · Post by **MartinM** » Wed Jan 02, 2008 9:10 pm

Hi Brett

AVR Studio 4 files attached. Enjoy!

Any questions, just ask - post here or PM.

Let me know if they make sense - if so, I'll post the schematic ....

Regards
Martin

Spockie-Tech · Post by **Spockie-Tech** » Thu Jan 03, 2008 10:22 am

Thank you very much Martin !

Got them open in AVR Studio and perusing them now.

AVR Assembly code is new to me ( did some 90s1200 code a few years ago), but I've done plenty of coding on Pics, Z8's, 68x and so on, they're all similair, so its looking straight forward enough.

get an ADC input, use that as an offset into a lookup table to compare against an interrupt driven counter. nicely formatted

I've been meaning to get into some AVR coding for a while (I have a Mega32 and 90Can128 on the bench here to do some Can/Lin bus projects for my car as well a Megajolt)) - so this is a good excuse to get moving on it

Now I need to do some datasheet browsing - The Tiny I have is a 15L - I have to see what the difference between that an the 13 is.

If you have a schematic handy that would be useful, but with only 8 pins, I'm sure I can figure it out if its not convenient.

Has anyone thought of adding a temperature input to the MJLJ ?

I was thinking of analog tweaking the Map input with a coolant sensor modifier so as to pull the advance back a bit on hot days without having to mess up the existing code or configurator.

jonboylaw · Post by **jonboylaw** » Wed Mar 12, 2008 11:07 pm

I also would welcome a circuit diagram.

Jon

MartinM · Post by **MartinM** » Wed Mar 12, 2008 11:47 pm

Sorry chaps - completely forgot

Here's a very badly laid out schematic on a scrappy piece of paper inelegantly scanned...

jonboylaw · Post by **jonboylaw** » Thu Mar 13, 2008 7:53 am

Cheers Martin

Autosport Labs

MJLJ Stimulator...with some pics

MJLJ Stimulator...with some pics

Circuit diagram please :)