From: <s-m...@tr...> - 2000-10-25 02:23:31
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-=> On Tue, 24 Oct 2000 15:20:05 -0700, "Bill Sobel" <bs...@vi...> said: > But, I want to find a way to limit the number of RF receivers I > have. Does anyone know of a 'universal' receiver (e.g. supports > multiple if not all house codes simultaneously)? How about the > MR26A, can that receive all the RF commands and then have MH > actually transmit them? For me, this is the Holy Grail of X10. I'm so tired of the long delays, RF collisions, and general unreliability of the Motion->RF->TM751->PLC->CM11->RS232->PC path, I'm determined to find a solution. Last weekend I started a project to get rid of RF receivers. As I see it, there is no need for an RF->PLC receiver when a PC with a server like MisterHouse is available. The commands should go straight from the transmitter (handheld, motion, security) to the PC and the PC can decide what, if anything, should be sent out on the PLC (with collision avoidance). Inside the TM751 there is an RF receiver daughterboard. (Schematic available here: http://www.geocities.com/ido_bartana/toc.htm) I tore one out, and connected it to an RS-232 port directly, so that the RF output data wiggles the DCD line. Then it was a simple matter to go get the Linux LIRC project to think it's an IR receiver module and match patterns on it. (The "xmode2" program is especially interesting, as it lets you watch the RF pulses. I'm finally getting an idea of how busy a house full of X10 RF stuff can be. There's a lot of chatter.) It looked promising at first, but now I find that the RF receiver in the TM751 is noisy, has poor gain control, and very short-range. I won't be able to receive the whole house (or a whole room) with just one antenna. Other ideas are the MR26A, which is only available as part of yet-another $70 videosender package. I have heard that this too is low range, and there may be bugs in the firmware to decode RF. (It wouldn't surprise me to find the same daughterboard in it.) I'm tempted to design a receiver from scratch -- something with a nice antenna, good front-end, smart gain and filtering. Unfortunately, that's incredibly beyond my RF understanding. :) In the meantime, I'll play with antenna enhancements and tweak the TM751 board. The LIRC code seems well-suited to decoding the RF commands, so I'm content to do it on the host instead of in a microcontroller. If anyone else is working on an RF to PC interface, I'd love to hear about other approaches. If one was available for sale, I'd pay major bucks for a well-made X10 PC receiver. It would be a great improvment to X10 speed, reliability and flexibility. -Steve |