dem@larry.UUCP (Donald Michalski) (12/18/88)
I would like to design an ultrasonic remote control transmitter and receiver that our astronomers can use to control the University's telescope. Motorola did make a CMOS chip set (MC14457 & MC14458) but they no longer do. I did manage to get a few sets but the receiver, MC14458, has difficulty "waking up" following power-up. Manually forcing Power-On Reset has no effect. Repeated blasting by the transmitter will eventually get it going but it's tough. Once up, it works fine. This could explain why the chips are no longer available. Note, the ceramic resonators have a 1% tolerance and reasonable care was used in laying out the receiver section. If anyone has had experience with these ICs and have found a fix for this problem, I would appreciate hearing from you. If alternative ICs are available from other manufacturers, please tell me. Respond to the address below. Thanks in advance. Don Michalski dem@larry.sal.wisc.edu University of Wisconsin Space Astronomy Laboratory