Thread: Universal Remote Cicruit

Hey Everyone,

I'm interested in how a universal remote control works. I can't seam to find any good circuits online . I'm not interested in the firmware or anything, just learning about the circuit of a standard universal remote (with no learning features, just a USB port or something). My best guess is there are a bunch of tact switches, an integrated circuit, a transistor, a few capacitors, resistances, diodes, an infra-red LED, battery casing and something else I can't work out? A circuit diagram or something would be really nice .

Thx
Antoine

I thing this would be better off in Eleectrical and Electronics, so have moved it.

Meteor Wayne

Originally Posted by Ant1

Hey Everyone,

I'm interested in how a universal remote control works. I can't seam to find any good circuits online . I'm not interested in the firmware or anything, just learning about the circuit of a standard universal remote (with no learning features, just a USB port or something). My best guess is there are a bunch of tact switches, an integrated circuit, a transistor, a few capacitors, resistances, diodes, an infra-red LED, battery casing and something else I can't work out? A circuit diagram or something would be really nice .

Thx
Antoine

It's not clear exactly what level of detail would be appropriate to answer your question, so sorry if this is more basic than you want. In any event, we can start here and veer off as desired.

An IR remote is dead simple at its heart: It's just an infrared flashlight. Commands are encoded as specific on-off patterns. There are several quasi-standards for the underlying clock frequency that determines the basic on-off time durations, as well as for the meaning of the on-off code patterns themselves. The clock frequency generally lies in the octave between 30 and 60kHz, with 38kHz seemingly quite popular (based on my totally unscientific sampling of the few remotes I've opened up over the years).

So the block diagram is trivial: A memory to store the code patterns, logic to get the memory to output the desired code bits serially in response to key depressions, a clock to drive the logic, and driver circuitry to light up the IR LED.