Searching \ for '[PIC]:IR receiving serial data , explanation sough' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/microchip/ios.htm?key=ir
Search entire site for: 'IR receiving serial data , explanation sough'.

Exact match. Not showing close matches.
PICList Thread
'[PIC]:IR receiving serial data , explanation sough'
2001\12\06@221411 by PICLIST

flavicon
face
Hi, I have an IR xmitter sending the string "1234567890abcxyz" over my
setup. (F628 - PWM 40khz carrier, RB2 TX 1200 baud).
The receiver is a F84 hooked to an LCD with the RX hooked directly to a
GP1U26x module.
The strange part is I have the two units 3 feet apart on my bench, when
xmitting on a straight line of sight, I get about 60% errors in the string.

However, when I place my hand directly in front of my two diode emitters,
I get 100% accuracy everytime ? Could somebody explain this or possibly
a solution ?
Thanks,
Kevin

Xmit Circuit was figure 6 from
http://www.rentron.com/Infrared_Communication.htm

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email spam_OUTlistservTakeThisOuTspammitvma.mit.edu with SET PICList DIGEST in the body


2001\12\06@225343 by Matt Pobursky

flavicon
face
On Thu, 6 Dec 2001 22:12:44 EST, .....PICLISTKILLspamspam@spam@MITVMA.MIT.EDU wrote:
>Hi, I have an IR xmitter sending the string "1234567890abcxyz" over my
>setup. (F628 - PWM 40khz carrier, RB2 TX 1200 baud).
>The receiver is a F84 hooked to an LCD with the RX hooked directly to a
>GP1U26x module.
>The strange part is I have the two units 3 feet apart on my bench, when
>xmitting on a straight line of sight, I get about 60% errors in the string.
>
>However, when I place my hand directly in front of my two diode emitters,
>I get 100% accuracy everytime ? Could somebody explain this or possibly
>a solution ?
>Thanks,
>Kevin
>

Possibly your transmitter is powerful enough that it's swamping the receiver photodiode or amplifier?

Putting your hand in front of the emitters blocks/scatters enough of the signal that the receiver gets a reflected or attenuated IR signal and that doesn't swamp the reciver circuit.

I've seen this happen before when directing a handheld transmitter directly at a receiver from a foot or so away. Maybe try reducing your transmitter LED current or only use one LED?

Matt Pobursky
Maximum Performance Systems

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email listservspamKILLspammitvma.mit.edu with SET PICList DIGEST in the body


2001\12\07@054825 by uter van ooijen & floortje hanneman

picon face
>  Hi, I have an IR xmitter sending the string "1234567890abcxyz" over my
> setup. (F628 - PWM 40khz carrier, RB2 TX 1200 baud).
> The receiver is a F84 hooked to an LCD with the RX hooked directly to a
> GP1U26x module.

How do you modulate the data onto the carrier? I don't know the Sharp
receiver, but the ones I know are not designed to handle a 'continuous on'
signal. They need 'off priods' in the signal, like all IR codes have. Maybe
your signal oversteers the receiver?

Wouter

--
http://www.piclist.com hint: To leave the PICList
.....piclist-unsubscribe-requestKILLspamspam.....mitvma.mit.edu


2001\12\07@124805 by kben

picon face
Hi Wouter,
The circuit is figure 6 on this page
www.rentron.com/Infrared_Communication.htm
I feed the 40khz carrier and the serial data into a
74HCT132 2 input NAND Schmitt Trigger.


{Quote hidden}

--
http://www.piclist.com hint: To leave the PICList
piclist-unsubscribe-requestspamspam_OUTmitvma.mit.edu


More... (looser matching)
- Last day of these posts
- In 2001 , 2002 only
- Today
- New search...