On 3/03/2008 07:00 Franc Zabkar wrote:
On Sun, 02 Mar 2008 23:28:28 +1100, Bob Parker
put finger to keyboard and composed:

This remote control uses a SC6622 chip which has a minimum operating
voltage of 2.2V.

It was difficult to connect an oscilloscope across the battery
voltage to see exactly what was happening, but I suspect that after
sending out the first code burst, the battery voltage momentarily dipped
low enough to reset the chip, causing it to send the 'leader' bits out
again as though the button had been released then pushed again.

Yes, they pulse the IR LED to relatively high current levels. As far
as I could tell by looking at the PCB tracks, there's only a 2.2 ohm
resistor in series with the LED.


Bob

I'm betting that fresh alkaline batteries wouldn't exhibit this
problem. Did you measure the ESR of the batteries?

- Franc Zabkar


I didn't measure the ESR of the batteries but I agree. The unit and
remote were only one week old. It took that long for the impedance of
the cheap horrible Chinese carbon-zinc AAA cells supplied with the
remote to increase enough to make it start playing up.

Bob