Go Down

Topic: Control multiple IR devices (Read 973 times) previous topic - next topic


What's your power source? Which transistor?


2N3904 and a bench power supply


200mA current transistor and a worthless description of a power supply. Gonna have to do better than that.


I tried with a S8050, I don't have anything more than 700 mA, but so far it doesn't seems to make any difference.  The power supply is HY3005D at 5V.


Does 13 not already have a current limiting resistor for the onboard LED?
And actually that may be why your range is dismal.
No. Pin 13 on an Uno-R3 is buffered by an opamp.
The opamp drives the onboard LED, not the pin itself.


How do you power the Uno.
External power on V-in or DC jack. What voltage.
Do you have a link to the IR diode.
Is it a narrow angle or wide angle type.

If you want maximum IR power directly from a pin, then try a 22ohm resistor and three IR diodes in series.
Spread them about 30-45 degrees.

Better to use an external transistor, e.g. the 2N2222, and drive the LEDs to 100-200mA (pulsed).


If more power is actually making it to the LED, then there is no way it "doesn't make any difference".

Hopefully you're not confusing distance with spread. More power gives more distance, but the cone of dispersion is fixed. The beam angle is usually very narrow on IR LEDs otherwise it'd trade off a lot of distance for wasted spread when you generally aim at the device you want targeted.
With a fixed beam angle, the spread is dependent on distance from the LED.


The distance is okay, the problem is the spread, I would need to make a stand practically as high as me to make it work. I just want to be able to let the arduino on the table. If I place the original remote on the table I can control the AC, but not with the arduino.

I'm saying that I don't see any difference, but for sure my tests are not really scientific, so maybe there is a little difference, but nothing that I can easily see.

I don't really need (for now) a wider spread horizontally, I need a wider spread vertically.


On a round led, the horizontal and vertical spread will be the same... If the spread is the problem then I would look for another led. Still haven't seen you post data about the led so it's a bit hard to say. But looking at all my remotes, I don't have to aim that much so the angle is alright.

Or you could modify the lens of the led. In the past I have snipped off the lens of leds to make them wide angle. Never did it on a IR led.

Yeah, and driving it harder can help etc. But in most remotes it's also directly driven and it works pretty well.
Use fricking code tags!!!!
I want x => I would like x, I need help => I would like help, Need fast => Go and pay someone to do the job...

NEW Library to make fading leds a piece of cake


Not sure if you can find a strawhat IR led.
If you have multiples of your led then time to wire them up. Walls of standard rooms typically bounce enough light to get near omnidirectional but your environ may vary.


I can't find them in my ebay purshare history, but I think they are like these one.

Is there a type of led that would be better suited for me ?

On a round led, the horizontal and vertical spread will be the same...
I know ! I meant that adding more led could help horizontally, but not vertically.

Go Up