LED status monitor

[betlit]

well, i'm also not that deep into electronics, too.

the simplest method is hooking up a standard LED with a 220 ohm resistor to D0, D1, D2,...D7 (+5V). as ground, you can take any pin from G0-G7.

i made a little image (ok, the image of the port is stolen from a website...) to show which pins on the parallel port are used to wire up the LEDS.

of course you can hook up a more complex circuits too. a standard parallel port gives you 5V and up to 15 mA current. this should be sufficient for most circuits.

i will add this diagram to the zip-file.

[edit]attached image removed. see this post for the latest version of the "circuit" http://forums.gbpvr.com/showpost.php?p=4...stcount=39

daniel

[valkokir]

Cool thanks,

I just found info on how all this works (I like to learn something while I'm at it)

http://www.epanorama.net/circuits/parallel_output.html


Also considered the possibility of using the keyboard leds to show status, however, most of us use wireless RF keyboards for HTPC use and the keyboard status lights are on the receiver...

[valkokir]

Works great guys, thanks. I do wonder about the resistor on the setup as 470 ohms seems a bit high. The led is sort of dim. assuming the led is 1.9 volts the supply is 5volts and it is a 15mA led... (5-1.9)/.015=206ohms...

It's bright enough to see, just doesn't match the rest of the LEDs on my system.

I made a harness to run from the back of the system into the case and up to the unused COM led on my case. Swapped in a red LED for the record function and works great. Of course I did a nice job shrink tubing and insulatin geverything so it would be too hard to change out the resistor to make it worth it.

Thanks again

[betlit]

i'm pleased to hear that :-)

uhm.. yeah... a 470 Ohm resistor is common when operating with 9-12 volt...
i forgot to consider that we're operating with 5V here.
this is my fault, sorry.

i changed the circuit.jpg and replaced 470 Ohm with 220 Ohm. better this way? *g*

daniel

[smeghead]

Sub,

This seems like a brilliant idea but one of its limitations as specified in the readme that is part of the software download is:

limitations:
if you watch live-tv and hit the recording-button on the remote, or by
browsing the mini-tv-guide, going to the current (running) show and
selecting (quick-)recording, diode2 will _NOT_ become active, because
these recordings get the status 'ready' instead of 'in progress'.
probably, because you are acutally watching them.

Is this fixable - it's a wife acceptance factor thing!

Cheers

[betlit]

i'm about to fix this by checking every record manually (like in the shutdown-plugin v2). kinda like:

loop until all recordings are checked or the LED is allready active
is Recording(i).startTime >= now and Recording(i).endTime <= now then
set led active
end loop;

this means: the service consumes a _little_ more resources. at the moment i allready loop over all scheduled recordings and check their status.
i just change the if inside the loop.

i'm busy at the moment (ok... i just want to watch a tv show (of course with GBPVR)). i will change and upload this about 1am (GMT+1 *g*)

edit: ok. it's done and the post with the zip-file is updated.

have fun

daniel

[jimh]

Betlit:

Great work - any chance of posting Radioshack part numbers for the LED's and resistors? RS sells 1/4 watt and 1/2 watt resistors - novices like me wouldn't know which rating is needed for this project. Also, RS sells blinking and non-blinking LED's with various ratings - again, any help on identifying the appropriate parts would be greatly appreciated!

Thanks,

Jim

[betlit]

the red LED i would buy at radioshack has a voltage drop of 1.7V. the parallel port gives you 5V, 15 mA)

R*I=U --> U/I=R

for the red LED (as valkokir allready mentioned) this means:
(5V-1.7V)/0.015A ) = 220 Ohm

the green LED has has a maximum voltage of 2.8V (minimum 2.1V):

(5V-2.75V)/0.015A = 150 Ohm

as we know both (the current and the voltage) we can calculate the power:

I*U=P

0.015A * 5V = 0.075 W = 75 mW

so a 1/4W (250mW) resistor would be more than enough.

the parts:

red LED: 276-307
green LED: 276-304
resistor 150 ohm: 271-1109 (package of 5)
resistor 220 ohm: 271-1313 (package of 5)

if you want to use the blinking LED (cat # 276-036) you would have to find a resitor between 160 and 180 ohm (radioshack does not offer such resistors but you can e.g. use a 150 ohm and a 20 ohm resistor (serial!))

this are just examples, of course... with these formulas, you can easily calculate the resistors for any LED.
i will add the calcs and part-numbers to the readme.

i did not expect that more than one person is interested in this (i made it on 'special' request). if some more people will use this, maybe this little thingie will make it to the utilities-section of the GBPVR-wiki? *g*

have fun

betlit

[alex060670]

@ betlit:

Thank you for the support. I tried the program yesterday (I actually couldn't find the corrrect jack, so I couldn't try the hardware part ;-)...

What I noticed was the incredible high amount of CPU usage when the service has been started -> 14% (!) of my Celeron M 360 (1400MHz).

Is that normal?

Greetings, Alex

[alex060670]

Hi,

I finally found an old 25-pin-jack, mounted the two LEDs on it, put it onto my PC. Works.

But:

1.) The running service still consumes 14% of cpu capacity. Would it be significant less usage if the "live-tv and hit the recording-button on the remote"-thing would NOT light up the red LED?

2.) It seems the service recognizes the machine waking up from hibernate but not gbpvr frontend to be started by wake.cmd (which happens to be about 10 seconds later)

3.) WITH THE NEW SERVICE RUNNING MY PC DOES NOT GO DOWN TO HIBERNATE ANY MORE!

Am I doing anything wrong?
Greetings, Alex