[mythtv-users] OT: IR LED testing...

[Dan Morphis]

Chris Petersen wrote:

>> I've got Enrique Vidal's circuit working 
>> (http://www.lirc.org/improved_transmitter.html).  Works great.  The
>>  only problem I had is I had to put a resister in before the ir led
>> as I kept burning them up.  I think I put in like a 500 ohm.  If
>> you want NTE part numbers I can get them for you.  I used 1n4148's
>> for all 4 diodes in that circuit.  I'd prefer not to (mainly
>> because its a pain to get it back together, and the circuit is a
>> mess), but I can take a picture of the top side of the circuit if
>> you want.  The bottom side will be impossible as it's held down
>> with about 2 glue sticks worth of glue :-)
> 
> 
> Well, I'm more interested in getting something I can use to etch a
> pcb (or in my case, wire up one of those hole+copper pcb blanks from
> radio shack because I don't have etching solution, etc).  Don't worry
> about it.  However, a list of part numbers would be great.

I got one of the RS prototype boards. I didn't use the one with just the 
copper holes for everything (this style: 
http://www.radioshack.com/images/ProductCatalog/ProductImage/276/276-148.jpg), 
I got the one similiar to this 
http://www.radioshack.com/images/ProductCatalog/ProductImage/276/276-170.jpg.


Radio Shack Part Numbers:
diodes: 276-1620
npn: 276-1617
pnp: 276-1604

I can't find the part number for the infrared project box I used. 
Everyhting else in the circuit you should be able to find.  The RS store 
I went to for some of the parts didn't have a few of the resistors, so 
for the 22ohm one, I had to put two 10 ohms in series to get close to 
the right value.  You may have better luck at an electronics supply 
house in your area.

Here are the NTE parts for the actual transistors I used:

NTE123AP npn transister
NTE153   pnp transister


> btw, did you use two IR LED's (along with the resistor and visible
> one)? If not, that'd explain why you were burning them out...

I couldn't get it to work w/ two. But I did use some I scrounged up and 
one of them could have been blown.

-dan