310Mhz transmitter circuit design needed

[jfigge]

I'm a newbi and have a fun project for my kids, but needs some help...

The background: 

After a recent trip to Great Wolf Lodge the kids came back with a couple of MagiQuest wands (Tilt switch wands with an IR blaster putting out a custom id per wand).  Using an ATTiny85 I can read the wands Id and would like to create a small device that I can place in each of the kid's bedrooms to control their X10 bedroom light switch.  The challenge is how best to interface with the X10 system?

Option 1) Have the bedroom controller wirelessly talk to a 'server' controller that can send X10 commands -> Easy to do over 315/433 Mhz but I don't really want to run a server
Option 2) Simulate a 3-way switch using a triac and have this toggle the switch directly -> Don't know how a companion switch works + direct access to mains electricity is scary
Option 3) Send a 310Mhz signal direct from the ATTiny85 to the X10 receiver module - Bingo!

#3 is my preferred solution but for neither love nor money can I find a 310-Mhz transmitter module?

* Can a 315-mhz module be 'tuned' to send 310Mhz signals?
* Does anyone have a circuit diagram I could follow (remember, I'm a newbie) that will construct a basic transmitter?

Any help would be appreciated
Thanks,
Jason

[radioactive]

Take a look at the Ti CC1125 transceiver.  It covers 273-320 MHz with LO divider of 12.  It is very flexible when it comes to making something compatible with existing devices.  I'm not familiar with X10 wireless protocol, but I would guess it isn't all that complex.

Quick search reveals:
https://en.wikipedia.org/wiki/X10_(industry_standard)

RF protocol
To allow for wireless keypads, remote switches, motion sensors, et cetera, an RF protocol is also defined. X10 wireless devices send data packets that are nearly identical to the NEC IR protocol used by many IR remotes, and a radio receiver then provides a bridge which translates these radio packets to ordinary X10 power line control packets. The wireless protocol operates at a frequency of 310 MHz in the U.S. and 433.92 MHz in European systems.

[edit]

Out of curiosity, I did a bit more searching.  It does appear that X10 uses OOK  (on-off keying), so the CC1125 should work for that or you can probably find something cheaper/more modular for something simple as OOK.  Here is a couple more links I ran across that might help.

http://www.linuxha.com/athome/common/x10.rf.html
https://www.rfwireless-world.com/Terminology/X10-basics.html

[edit] add note about LO divider / freq range to be clear.

[jfigge]

First, i'm going to say thank you for responding.
Second, thank you for a very helpful response!
Third, that chip is WAY over my head . Even if I could figure out how to use it I'm not sure I could figure our how to solder it!

Interestingly, though... Last night I looked at the decorator switch for an x10 3-way switch and it is ridiculously simple.  All the remote switch does is close a circuit between the live and control wire that travels to the secondary switch.  So a simple relay or triac could send a brief pulse and the x10 main switch do all of the hard work and toggle. As soon as I get the necessary components I'll give that a try.

Thanks again for the solution,
Jason

[uski]

Hi,

If you need an ASK/OOK transmission, you can use a cheap eBay 315MHz module and change the resonator to a 310MHZ model. I did exactly that to make a copy of my garage transmitter remote which works on 310MHz and it works fine.

I got a pack of 310MHz resonators on eBay (here is a link)
Make sure to get a 315MHz module that uses a resonator at 315MHz in this package. Some use a crystal with a PLL and you can't do this. In general, if there is a round package like this, you're good, especially if it says "315".

It's probably the cheapest and simplest solution.

Don't forget to use a proper antenna for 310MHz.

[ebclr]

https://www.aliexpress.com/item/32971119720.html?spm=a2g0o.productlist.0.0.3c943e24qXcC7y&algo_pvid=cc60bc49-c72f-4682-be3e-a211727c0d4c&algo_expid=cc60bc49-c72f-4682-be3e-a211727c0d4c-3&btsid=0a95264d-25ef-45ef-a149-8a3044167de1&ws_ab_test=searchweb0_0,searchweb201602_9,searchweb201603_52

[oPossum]

A few other ways would be using a PL513/PSC04, TW513/PSC05, or CM17A/Firecracker.

The CM17A protocol is simple and does not require precise timing.