aic@s.cc.purdue.edu (George A. Basar) (09/08/88)
Problem: I have acquired a second color t.v. that I wish to put in my bedroom, being the lazy programmer that I am.(My PC sits right next to the bed also). I've built a relay for the remote control of the cable converter and it works fine except for on hitch. The relay doesn't talk to the converter box. I basically have an I.R. detector driving some logic which translates the signal to digital, then wires that to the emitter(815nm) which sits in front of the cable box (very close proximity). Question: Why doesn't this work? a.) Wrong frequency of I.R. emitter b.) Some type of optical filtering c.) I am totally off base on my design(always a possibility since I am a programmer and not an EE) Helpful hints are welcome and appreciated in advance. Thanx George
pfales@ttrde.UUCP (Peter Fales) (09/08/88)
In article <3542@s.cc.purdue.edu>, aic@s.cc.purdue.edu (George A. Basar) writes: > I've built a relay for the remote control of the cable > converter and it works fine except for on hitch. The relay doesn't ^^^^^^^^^^ > talk to the converter box. I basically have an I.R. detector > driving some logic which translates the signal to digital, then wires > that to the emitter(815nm) which sits in front of the cable box > (very close proximity). > Question: Why doesn't this work? I am not sure what "works fine" means in this context, but I have done some playing around with IR detectors and have experienced similar problems. Typical (e.g. Radio Shack) bipolar Photodiodes and Phototransistors are not fast enough to detect the typically 40 KHz carrier used by IR controllers. A PIN diode such as the TIL 413 or SFH205 must be used (I purchased mine from Active Electronic Sales). Typical receivers are broad-band enough that when used in close proximity to the transmitter do not require a great deal of concern over frequency or filtering. -- Peter Fales UUCP: ...att!ttrde!pfales work: (312) 416-5357 AT&T, Room 2F-217 200 Park Plaza Naperville, IL 60566