From: Sam Varshavchik <mrsam@co...> - 2001-07-01 14:45:00
Cameron Patrick writes:
> On Sat, 30 Jun 2001, Sam Varshavchik wrote:
>> It's working fine except that there appears to be a lot of noise coming out
>> of the receiver. When it's laying out in the open, I read occasional blips
>> from the receiver, about 150-200ms. If I hold a remote control up to the
>> receiver's eye, and cover everything up, the noise goes away and I can get a
>> good reading.
> It sounds like it's picking ambient light. Have you tried it with the
> light turned off? The LED that I have (the only one that you can get in
> Australia) claims to have an ambient light filter built-in. I'm not sure
> whether the Radio Shack one does, though.
> I'm not sure if this will help, but you could try putting something black
> behind the receiver (e.g. some card or plastic or whatever).
Heh. Turning off the lights in the room does indeed get rid of the noise.
I still get a little junk when I open the serial port. Which, I suppose is
to be expected, while the circuit stabilizes.
>> Also, if I shine a regular flashlight into the receiver, the
>> noise stops too.
> Yes, but if you shine a flashlight into the receiver, you're not going to
> be able to pick up anything from a remote control with it, for the same
> reason that if I shine a flashlight into your eye, you're not going to be
> able to see an awful lot ;)
Actually, no. If I shine a flashlight into the receiver, the noise readings
stop. Then, if I press something on the remote control, while still shining
the flashlight on the receiver, I get a clear reading.
Figure that one out.
From: Mike Ricketts <mike@ea...> - 2001-07-07 11:36:53
On Sun, 1 Jul 2001, Sam Varshavchik wrote:
> Actually, no. If I shine a flashlight into the receiver, the noise readings
> stop. Then, if I press something on the remote control, while still shining
> the flashlight on the receiver, I get a clear reading.
Makes sense if it has a not very clever background noise filter, which
simply adjusts the level that is regarded as no signal.
With the lights off, that level is pretty constantly very low. With a
flashlight shining in to the remote, that level is constantly very high.
In "nornal" situations, the amount of background light varies when, eg,
people walk between the light and the sensor. It is that variation that
is generating the noise.
Mike Ricketts <mike@...> Phone: +44 7968 381810
Hate is like acid. It can damage the vessel in which it is stored as well
as destroy the object on which it is poured.