Fred's FreeEMS prototyping hardware thread NO 56K,DSL beware

[Fred]

Upgraded the power supply to dual lm2940 devices and heatsinks. The power pack attached is not up to the task the rest is now, but it seems to survive without catching fire and I don't leave it alone when I'm not devving anyway.



Back to the code.

Admin.

[Fred]

It just occurred to me that the reason the caps weren't working was that there was no "pull back up" happening. I.E. the signal was being pulled low and the cap discharged by the transistor on the JimStim, but when the transistor switched off, the signal was staying low as you would expect. It would be nice to scope some signals and watch their behaviour with various setups in a controlled and measured scientific way. Perhaps one of you can do that with a simple square wave and resistors and caps. This also explains the false signals I was getting somewhat. the rising edges would have been at a very shallow angle. Because of that and other Voltage drops, the trigger point would have been crossed multiple times as it went by.

This should have been obvious, but it's all a learning process :-)

Admin.

[Fred]

I just snapped these for a VERY inquisitive guy on a forum and thought I'd post them up, they are just the latest way it all looks, nothing exciting. The wires and RCA jacks are for hooking to the sound card scope, 2x JimStim, 1x Fuel, 1x Ignition.





Fred.

[Fred]

Bump from the dead :-)

I was looking at this picture anticipating the arrival of my new second hand ECU and thought I'd take the DB9 out through the thin part of the back side of the case opposite the connector. That way I can lay a PCB along that back side over the CPU etc and keep away from the taller components closer to the connector.

So, to ready my board for that I desoldered the RS485 connector and trimmed the two header plugs with a knife :



That way it should fit up to that recess nicely and without binding on the case.

Fred.

[Fred]

Today I pulled the two LEDs off the TA card and beveled the edges of the corners of the board where the copper ground was exposed such that if it rests against the enclosure I don't get a funky ground loop. It still works nicely :-)

I also did some research into the remaining pin outs on the test mule ECU so I'll be logging ignition timing and dwell with it too.

Fred.

[Fred]

Some news! Alan To of www.14point7.com was nice enough to post me a couple of JAW units to assemble and use. Thank you very much to Alan for that! I can't wait to throw them together so I might do one or part thereof tomorrow some time. I still need to get a case and some wires and a sensor for it/them though, so there is lots to do.

Additionally I need to modify my precious dev setup to conform to the new way that Sean has suggested. Ironically the thought of using those two pins crossed my mind ages ago and i went for the even numbers instead... silly fred.

Lastly I need to mod that toy ecu i have to accept a ta card.

that and a stack of code

it still may be possible to run by end of feb... but we'll have to wait and see i guess.

Pics of JAW to come soon!

Fred.

[Fred]

Due to other pressing matters I didn't get to the JAW construction just yet. I did snap some pics for this thread of my test rig stuff, but can't post that just yet...

This weekend was pretty unproductive overall. This week and next weekend will have to be epic successes to make up for it.

Fred.

[Fred]

Wow, haven't put anything in here for a while! :-)

Yesterday afternoon I drove my FreeEMS powered Volvo up to DIYAutoTune and purchased an upgraded JimStim chip for my JimStim. While I was up there I gave Jerry a quick ride in the car - just down the road and back - understandably he didn't seem too happy about it, but never the less, it is what it is.

Jean, my JimStim chip has 2.0.3 on it, tell me about what I bought :-)

Fred.