IR transmitter led021

H

huttonart

New Member
I'm making some simple mistake but can't figure it out. I've set up the IR receiver circuit as per Hippy's factsheet and it works fine with the TV remote- many thanks for that. Now I'm just trying to get the IR LED to work on another 08M by connecting it between Output 0 and 0V via a 220R. using this code:
transmitloop:
infraout 1,005
pause 45
goto transmitloop

I'm not trying to send a message, just to send an IR signal.
An ordinary LED in place of the IR LED works fine - i.e fast flashing, but with the IR LEd in its place I can't see any IR output using the dig camera. Any ideas please?
 
B

boriz

Senior Member
Yep. Hippy has it. Prolly in backwards. I have done the same thing myself. For some reason, some IR LEDs have the Anode on the Short leg.
 
H

huttonart

New Member
Thanks Dippy & Boriz

It's the Picaxe LED021 and though there's no data sheet on the product page they say cathode is flat and that's what I've been using. (Turning it round makes no difference)

I bought two and used them straight out of the packet. Also follwed advice given in a page from scilea.uk.com which advises caution when using IR LED's so I don't think I've damaged them in use. I tried the circuit on an ordinary LED before using the IR LED.

I'm using a 3*AA battery supply (fully charged) having read in a thread that using Infra in/out commands are sensitive to PSU noise. The 08M is on a proto board. No other pins are connected only Pin 0. If I just connect the IR LED in series with a 220R to a 4.5v supply it should just generate a contious emiision of IR, right? Enough to be picked up by a camera?
 
D

Dippy

Moderator
(That was hippy, not me :))

Just one question: hve you checked your digi camera can sense IR? (with a TV remote).
My Canon can see I/R but my Fuji can't so not all cameras are IR sensitive. Check with a known IR source first.

Yes, a few volts a res+IRLED should give something visble to an IR sensitive camera. 4.5V + 220R won't give much ooomph though.
 
Technical

Technical

Technical Support
Staff member
LED021 is normal shape LED, flat is cathode (-) as normal. Dippy is probably right about the camera....!

Remember the TV remote does not actually give out the number on the button - is this your original confusion? See the 'codes' comparision table under infraout in part 2 of the manual.
 
H

huttonart

New Member
Thanks everyone. The camera's a Cannon and its fine with a TV remote. Theres no problem with the Sony Protocol, I've just been cautiously trying to get an IR signal in the simplest way. Yesterday I went to Maplins and got another IR LED. It works fine as per Hippy's Basic IR Transmitting circuit and also just putting it series with a 100R receiver ( i.e a bit more ooomph) with a 4.5V battery pack. So I'm now assuming the IR LEds from rev-ed were dead on arrival.
 
H

huttonart

New Member
Erh Do... It was the camera - I just read on another forum that the best cameras for checking IR are mobile phones and yes it is emitting, somehow not enough for the Ccanon which was OK for the TV remote. So apologies to all but still very good to have feedback on double checking polarity, value of R etc. Thanks loads..
 
hippy

hippy

Ex-Staff (retired)
It's a very good lesson in the value of 'comparative testing' ( if this works then why doesn't that ? ) and the sensibility of replacing a suspect component with another less suspect; if they both don't work that suggests the problem is elsewhere, if one does work the focus can then be on why the one which does not will not.

Well done anyway; you identified the problem, and have discovered, "why" ? One cannot really ask for more than that.
 
B

boriz

Senior Member
Many cameras will have a built in IR filter, prolly makes the colours more natural when you filter out the IR.
 
You must log in or register to reply here.
Top