My solution to Auto Power ON Lilliput screen - Page 14

lazarus · 04-01-2005, 04:53 AM

despite haveing done no mods to my 7" lilliput it turns on by its self any way. its the newer revision of the board and its hooked up to an opus 90watt psu (positive and ground), i also remove it completely from the car on a night so it has kind of back up power but still it fires up by its self in the morning. when i get the a chance i'll go and check if there are any model/revision numbers on the back to compare against.

MatrixPC · 04-01-2005, 11:24 AM

Quote: Originally Posted by phc

FYI - Mod made simpler.

By leaving the resistor in, I've added just one 150uF capacitor and it works fine.

Getting a 150uF cap is tough, especially one that is not huge. I found a 6.3V one in DigiKey that is pretty good.

Quote: Originally Posted by joshthepilot

Since 100K and 10uF work, 100uF cap would also work in this setup.

I pointed this out on page 2 of this thread (post 29) but no one try it.

http://www.mp3car.com/vbulletin/show...6&postcount=29

Post 30 is Coyote reply
http://www.mp3car.com/vbulletin/show...8&postcount=30

[edit]correct link to Coyote post 30 [/edit]

MatrixPC · 04-01-2005, 01:34 PM

Quote: Originally Posted by joshthepilot

Yes you did. And now that I see it, I wish you would have rebutted against that this could be damaging.

The cap, regardless of size really has the same effect as the button. There is no way the charge would damage the mcu, the circuit, or the power button.

You have done it this way Matrix? And if so, tell us how well it works.

Nope I didn't mode my LCD for this auto on yet that is why I don't know how it works and how reliable it is.

looneeii · 04-06-2005, 11:03 AM

Anyone do this on the 8in liliput yet?

ming · 04-12-2005, 05:31 PM

works on lilliput 8" TS too.

the circuit is slightly different, with the switchboard connector on back rather than front, so I routed the - wire of cap through a hole to back to get a ground point, but front side is same.

Arathranar · 04-12-2005, 05:35 PM

Ooh! Thank you! Please post (many) pictures!

ming · 04-12-2005, 08:34 PM

the board is mounted on the back of the casing. second photo shows the whole board and 1st is how I soldered the resistor and capacitor -- the original resistor was removed. 3rd image shows where I grounded the cap on the back side.

looneeii · 04-12-2005, 11:56 PM

Very nice, thanks

fantomas · 04-13-2005, 12:09 AM

do the lights on the bottom stay on constantly now for the 8" as well?

Arathranar · 04-13-2005, 01:01 AM

Quote: Originally Posted by ming

the board is mounted on the back of the casing. second photo shows the whole board and 1st is how I soldered the resistor and capacitor -- the original resistor was removed. 3rd image shows where I grounded the cap on the back side.

What size cap / resistor did you go with? Ok - I know I could work out the resistor by digging up the details on how the color code but I'm sure you won't mind letting me take the easy way out by telling me

.

shotgunefx · 04-13-2005, 06:38 AM

Any specific reason to use an electrolyte cap as opposed to a non-polarized mylar or more rugged Tantalum cap?

ming · 04-13-2005, 08:28 AM

I used values in coyote's post -- 150k resistor and 10uF cap. I didn't pay attention to what type of cap, but for 10uF probably Al electrolytic ones are most common and cheap, I got a 20 assortment pack from radioshack for $4.29.

I think the button lights work as they should be, but I didn't pay much attention to that.

Arathranar · 04-13-2005, 10:31 AM

Its a different mod for the lights.

phc · 04-14-2005, 01:51 AM

Quote: Originally Posted by shotgunefx

Any specific reason to use an electrolyte cap as opposed to a non-polarized mylar or more rugged Tantalum cap?

Capacitor selection depends on many factors, Tantalums are great for voltage regulation to supress high frequency oscillations and have low ESR. Film caps are good for high voltage spikes, low leakage, etc..

In the case of the lilliput, you have a 5V signal that you are trying to delay. Super low frequency, super low voltage. No need to spec anything but a cheap-*** aluminum electrolytic, rated to 6.3V.

I use a 150uF, in combination with the on-board 10K-ohm resistor, giving you an RC value equal to a 150 k-ohm resistor with 10 uF cap.

23 cents at digikey

http://rocky.digikey.com/scripts/Pro...&M=UHE0J151MDD

Putting in a more expensive capacitor won't make it work any better.

shotgunefx · 04-14-2005, 03:01 AM

Thanks for the answer. I'll probably use the tantalums as I have tons of them.

Quote: Originally Posted by phc

Capacitor selection depends on many factors, Tantalums are great for voltage regulation to supress high frequency oscillations and have low ESR. Film caps are good for high voltage spikes, low leakage, etc..

In the case of the lilliput, you have a 5V signal that you are trying to delay. Super low frequency, super low voltage. No need to spec anything but a cheap-*** aluminum electrolytic, rated to 6.3V.

I use a 150uF, in combination with the on-board 10K-ohm resistor, giving you an RC value equal to a 150 k-ohm resistor with 10 uF cap.

23 cents at digikey

http://rocky.digikey.com/scripts/Pro...&M=UHE0J151MDD

Putting in a more expensive capacitor won't make it work any better.