MPGuino release one workspace - Page 35 - Fuel Economy, Hypermiling, EcoModding News and Forum

MilesPerTank · 06-19-2008, 08:55 AM

Gotcha

. I love the big numbers by the way.

Did you ever get your scope or do you still want me to hook one up on the top of the zener?

awillard69 · 06-19-2008, 09:43 AM

I plugged around with my setup. I ran the basic Freeduino board for a long time without the peripherals shield. It ran just fine.

So it must be something with the shield or it's components. I was checking voltages, signals. It was tedious. But once it reaches that state, it stays there until whatever condition dissipates, it just takes 45 minutes to reach it.

When I gave up for the evening I was out of ideas.

While the sketch compiled sizes may be different between Linux and non-Linux, I'm not certain that is what's causing the problem - see paragraph 1.

When I woke up this morning, I had a thought. My LCD has an 8+ inch ribbon cable connected to interface to the shield. However, not all of the leads are connected. I wondered if they are getting some kind of built up charge and causing the inputs to the LCD to enter this odd state. My thought was to tie them all to ground (logical 0). But, I didn't have the 45 mintues to reach the condition before work this morning.

Unless someone has a different idea, this is what I plan to look into this evening.

dcb · 06-19-2008, 10:05 AM

Glad you like the numbers MPT

re: scope, it is in route. And will take some work once it gets here. Were you going to double check the injector count?

re: LCD, all I can tell you is that I don't have anything connected to pins 7-10.

awillard69 · 06-19-2008, 10:09 AM

Like I said, it's just a thought. And I've got 8 inches of ribbon cable attached to mine. Those are just the other 4 data lines, aren't they? Any reference materials stating they should be grounded if not used?

My only other thought was to expunge the ribbon cable entirely and go with direct wire setup. But, I like the flexibility of not having the LCD not packed on top of the rest of the components.

Yoshi · 06-19-2008, 11:12 AM

Quote:

Originally Posted by RuHaSs

While we are on the subject of how harsh this environment is for electronics may I suggest LM2940T-5.0 as a replacement voltage regulator with the proper filtering.

Yes, the LM2940 has better specification data than 7805.
However, I believe the problem is caused by thermal overload protection.
I think we need some heat sink for the voltage regulator.
Would some tell us how hot the 7805 is?

Yoshi

awillard69 · 06-19-2008, 11:16 AM

Running on bench power (a PC power supply, 5v and 12v) at 12v, it is not warm to the touch.

Is it different when running on vehicle power?

MilesPerTank · 06-19-2008, 11:36 AM

It's worse when running high input voltages.

I posted a summary a few pages back.

awillard69 · 06-20-2008, 08:28 AM

Good news, tying the unused leads from the ribbon cable to ground solved the problem. It's been running all night long!

awillard69 · 06-20-2008, 08:32 AM

v.63 Ubuntu: 9964, 52%, 590 free.

Njay · 06-20-2008, 08:58 AM

I just want to leave a link to a post I did in another forum about auto transients you can get. I found an "auto surge transient tester" product from a Japanese company, and they have on-line the specs for the transients the generator is able to create. It seems that there's even a standard. Have some good readings

link to post