I've been using an IRman for years but recently bought a Sky Navigator remote to use with my mythbox, the reason being was that it had a keyboard which I thought would be useful. Anyways, the remote and IRman don't get on so I looked for a replacement. The IRman uses lirc anyway so I thought I'd build the 'homebrew' serial receiver.
I had all bar one of the components hanging around so I stuck a TSOP1738 on a recent CPC order and decided to build one.
The details are here:
http://www.lirc.org/receivers.htmlSchematic is here:
Code:
IC1 = TSOP 1738
+-----------------------+ 3 R1 (4k7)
| data -> +--------------------------------+------------o DCD
| | _______ |
| ______________ | | 78L05 | | | D1 (1N4148)
| / | +-----+-----|OUT IN|--+ | |
| ( | 2 | | + |__GND__| | | | /|
| \______________ + +----+ ----- | +----+------|< |--o RTS
| | ----- | IC2 | \|
| | 1 | |
| - +----------+---------+------------------------o GND
+-----------------------+ C1 (4.7µF)
To put it bluntly, it doesn't work. The serial port of every machine I have at home (7 or 8, must try harder) is seemingly unable to supply the voltage under load resulting in just over 3V going into the TSOP, not enough, the minimum is 4.5V. So, I decide to power it off the internal 5v rail via one of the molex's. The reg finally puts out a good 5V but this then shows up another problem, the data line is then tied high at 10V (the TSOP is running at 5 remember) and it melts the bugger (good job i bought a few).
Am I being an idiot, or is this design ill-conceived? Given this circuit is basically a reg, a cap, a diode and a resistor, it should work fine.... and they do, in isolation. Just bringing it all together seems to be the problem.