I think this might be the decoder chip on the R06. Found a clear enough photo of the R06 to get the chip #

http://www.adafruit.com/datasheets/PT2272.pdf

Per pg 6 you can drive an led thru a 560 ohm res for testing.

It would be interesting to measure the voltage on the output pin while driving the LED,
Both AC and DC.

Yes that's the one, thanks

 

I think that you should consider buying at least a cheap, used oscilloscope. It seems like you could put one to good use. If nothing else, at least download one of the free ones that runs on your PC and uses the sound card input, for low-frequency stuff, and playing around.

Thanks - I had no idea that PC oscilloscopes existed. I will investigate.

 

OK I seem to have solved it. On the assumption that the rx output was really a disguised pulse train, I put a 555 monostable with a period of about 0.1 seconds between the rx output and the mosfet gate. The 555 seems to drive the mosfet quite happily.

I also had to put an NOT gate in the chain because as far as I know the 555 monostable has to be triggered by a falling edge and the rx output gives a leading edge. To do this I used another 555, which is fine, but is there a simpler way?

Thanks for all the advice.

 

Just to recap - I was trying to drive a heating pad (resistance 10 ohms) with a 9V power supply, switching it using the 5V output of a remote control and a LL mosfet. The mosfet wouldn't turn on because the output was pulsed rather than steady. To solve the problem I added a 555 monostable that effectively lengthens the pulses, giving the mosfet time to turn on. And also another 555 as a NOT gate.

Which is all fine but I can't help thinking there is an easier way. Could I drive the heating pad directly if I used a power transistor rather than a mosfet? (Though the current through the pad is about 1A so I don't know whether I even need a v hefty transistor.) Given that the output from the rx is quite feeble, could I use a power transistor that incorporates a darlington pair?

 

....
Which is all fine but I can't help thinking there is an easier way. Could I drive the heating pad directly if I used a power transistor rather than a mosfet? (Though the current through the pad is about 1A so I don't know whether I even need a v hefty transistor.) Given that the output from the rx is quite feeble, could I use a power transistor that incorporates a darlington pair?

You could first try an RC low pass filter. You need a relatively low value series gate resistor with a capacitor from gate to ground.
Try a 1k with a 1uf cap. Better would be an RC low pass with a buffer.
Values are based on a guess that the frequency is an IR data pulse train. You could experiment with smaller resistors and larger value caps.

Edit: You could use a transistor. Just would have a bit more voltage drop when on. It appears the RX can drive ~ 5ma so you might need a 2A Darlington for some safety margin.

 

Thanks - you mean a transistor as an alternative to a filter/buffer?

 

Thanks - you mean a transistor as an alternative to a filter/buffer?

I meant a Darlington transistor instead of a Mosfet.

The RC filter would take the place of the 555 to smooth out the pulses from the RX.
Try that in place of the 555 to drive the Mosfet. May or may not work, but its simple to try.

A Darlington is easier to drive than a Mosfet. It would still be good to use an RC filter on the input.