X10 RF Transceiver (TM12U)

The TM12U transceiver module operates on the new UK supported frequency of 433Mhz and acts as the receiver to a range of wireless transmitters. These include the Keyfob, Stick-on Wall Switch, Hawkeye and External PIR.

[googlead]The module receives the wireless RF commands and transmits them as X10 signals over the mains.  The unit has a metal telescopic aerial mounted on the side which extends to around 20cms above the top of the unit. The range of operation depends on the transmitter. As a guide around 10 metres through walls with the keyfob.

The TM12U allows the use of all 16 unit codes on any 1 house code. You can of course choose your house code as usual by setting the dial. The unit also doubles as an appliance module which can be controlled locally via the on/off switch on the front. However, the module’s address MUST be unit code 1 on the house code you have chosen (e.g. if you set the unit to “M” then M1 will be the address of the built in appliance module. In practice this is a bit annoying. Before receiving the unit I had my macros programmed into HomeVision. “M1” is mapped to another module address but every time I send an “M1 ON” from the keyfob as well as getting the desired result I also get the dreaded relay “Click”. I have my unit placed in the hallway (to be as central as possible) and the noise is heard over a wide area (I think it’s even louder than a normal appliance module). It would be nice to have the option of disabling the internal appliance module to avoid this.

While testing the TM12 I came across a strange problem. As mentioned already I use HomeVision to map the housecode “M” (for macro) to various other codes around the house. This means that my 3 1/2 year old daughter (who can’t reach the any of the light switches) is able to control her bedroom lights plus the bathroom lights from a keyfob remote. The simple macro in HomeVision receives (for example) an “M1 ON” and then sent out a “B8 ON”. When I was setting this up first I sent the command from the keyfob I noticed the X10 send and receive lights on the front of HomeVision were constantly flickering. On closer inspection it transpired that the “M1 ON” command was continually being resent by the TM12. To cut a long story short I found the answer after posting to the HomeVision mailing list. Turns out the TM12 was seeing the “B8 ON” that HV sent out as a collision to its “M1 ON” and so resending it. As it resent the “M1 ON” HV of course sent out another “B8 ON” which was seen as another collision and so on… The fix is to insert a pause into the HV macro before it sends the “B8 ON”. Seemingly 0.02 second pause is the shortest that works reliably.

This unit allows the retro-fit convenience that you know and love from X10 to be extended to places that don’t have mains wiring. For example, place an eternal PIR at your gate and have a chime module sound inside when someone is entering your property.  The TM12 opens up a whole new world of possibilities!

Approximate Price £47.00.  Available From Lets Automate

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