V4 board suggestions

aarc240 · Post by **aarc240** » Fri Mar 02, 2007 3:21 am

As there will eventually be a board update at some time, here are a couple of suggestions.

1.
Reposition the Molex connector toward the opposite side of the case to make space available on the end plate for a bulkhead vacuum port in line with the sensor to eliminate stress.
There should be no need to fit a vacuum pipe with an S bend in it.

2.
Make provision for a current limiting resistor between the 'option' input pin and the zener diode.

Post by **brentp** » Fri Mar 02, 2007 4:21 am

Thanks for the feedback. Yes, I have a list of improvements to make... as they say, hindsight is 20/20.

aarc240 · Post by **aarc240** » Mon Jun 04, 2007 12:08 pm

Another one to add to the new version board.

Connect R5 to PIP - I used pin 9 of the MAX232 and disconnected R5 from U1 pin 13 / R1.

This eliminates most of the problems with the TACH-OUT signal and the existing R5 / T2 / R2 arrangement avoids loading PIP.

Post by **brentp** » Mon Jun 04, 2007 8:21 pm

So far there haven't been any reported problems with PIP current loading but it is a good suggestion regardless. Thank you again for the feedback!

aarc240 · Post by **aarc240** » Wed Jun 13, 2007 12:25 pm

Umm, hindsight really is better!!
I reconfigured my V3 board (again!) to pick up the PIP source signal from the X2 p2 / U2 p8 track, works just as well and is much easier to patch the existing board.
The track is adjacent to D7 and immediately above U1 and IC1. A small diameter sleeve is needed on each end of R5 and I also used a couple of dobs of hot-melt glue across the gaps between IC1, U1 and the body of R5 to protect against vibration.

david jenkins · Post by **david jenkins** » Thu Jun 14, 2007 5:39 pm

Another useful addition on the V4 board would be a USB port to replace the serial input. It could also mean the end of all those "my USB-serial adaptor doesn't work" threads!

I know that someone has adapted the megasquirt board, using a small USB add-on board.

cheers,
David

Post by **brentp** » Thu Jun 14, 2007 6:15 pm

But my love for usb-serial has no end.. and what would I ever do with my huge pile of different adapters?

Great suggestion, and one that's been on the forefront of my mind....

david jenkins · Post by **david jenkins** » Thu Jun 14, 2007 8:18 pm

If it helps, the one I saw used devices from FTDI

Gilesy998 · Post by **Gilesy998** » Fri Jun 15, 2007 1:33 pm

I remember there being talk of and EDIS-free version of mjlj possible in the future - and that I really fancy the idea of. I guess it'd mean pulling open EDIS4/6/8 modules, copying their schematics and adapting it's functions to fit on a single board.
Maybe even moving away from the EDIS altogether, I presume the result of such a project would be MJLJ V4.x/4, /6 and /8 - maybe even allowing for odd numbers of cylinders such as Audi's 5-pot, using a coil-per-plug arrangment. This would probably mean differing board latouts per cylinder quantity?

Post by **brentp** » Fri Jun 15, 2007 3:34 pm

As had been indicated before: Yes, there is a completely stand alone, non-edis version on it's way. I will be soon be announcing the firm details, including capabilities and rough pricing information. And yes, it will be a DIY-themed project in the spirit of Autosport Labs.

Thanks,

fikus01 · Post by **fikus01** » Sun Jun 17, 2007 10:13 pm

if you're going non edis then maybe a different or selectable type of trigger could be employed. maybe utilising static timing from a distributor!

i know there can be an amount of slack in an ignition system with a dizzy because of slack in the timing chain or work gears etc etc, especiall on a-series engines but just being able to have a customised ignition curve thats to within a couple of degrees of accuracy would be lots easier to plug and play that having to make a timing wheel and vr sensor fit in somewhere!

does that make sense!!

aarc240 · Post by **aarc240** » Mon Jul 02, 2007 3:28 am

David (and anyone else interested)
If USB is giving enough problems have a look at this one
http://www.dontronics-shop.com/product. ... ctid=16497
More out of interest than any real need I patched one of them onto a MJLJ in parallel with the RS232 interface and had USB working in minutes.

david jenkins · Post by **david jenkins** » Mon Jul 02, 2007 9:34 am

That's a useful looking device. It would be interesting to see if that could be piggy-backed onto the existing boards (not that I have a problem with the data - my antique laptop has a 9-pin RS232 port).

However, if Brent's going to the trouble of redesigning the board, then he might as well skip the RS232 bit and go straight from data to USB.

cheers,
David

aarc240 wrote:David (and anyone else interested)
If USB is giving enough problems have a look at this one
http://www.dontronics-shop.com/product. ... ctid=16497
More out of interest than any real need I patched one of them onto a MJLJ in parallel with the RS232 interface and had USB working in minutes.

aarc240 · Post by **aarc240** » Mon Jul 02, 2007 9:58 am

Dunno about skipping the RS232C altogether - I'd prefer to see the option of either/or installation.
USB doesn't like electrically noisy environments, particularly anything that puts out much RF energy.
Sometimes the older slow ways are actually better!
Maybe I'll have to search out a daughter board for RS232C that can be installed in much the same space as the USB one. That way either one or the other can be installed as the user prefers.
Given that hardware flow control is pretty much redundant these days, the RS232C board could break all the rules and use a connector physically similar to USB type B thus allowing one end plate to service both.

Oliver Sedlacek · Post by **Oliver Sedlacek** » Wed Jul 18, 2007 10:11 pm

Brent,
I'm working on a non-EDIS box, which I'm prepared to put in the public domain. Going non-EDIS certainly gives flexibility on trigger wheels, as it's all done in software. With four coil drivers, it could do 4, 6 and 8 cylinder engines in wasted spark configuration or 4 cylinder coil-on-plug. It's a bit more than Megajolt V4 though.