Hacking an X10 Mini Timer – Review


Submission by Mark Marooth – I plan to use my mini timer for switching a number of lights and other devices namely my home security system in a manner that was not originally intended for the humble mini timer.

Having obtained a number of Mini Timers from Homebase for £2.99 each, the first thing I needed to do was remove the electronics from the nicely styled case. Turning the case over I saw two screws at the back. There are in fact four screws to be removed, the other two are at the front under the rubber feet… I removed these feet by picking them off and unscrewed the four screws with a longish but slim Phillips head screwdriver. Once loose, it is best to open the case from the back.

When you get it open, it looks like the photo above. I unhooked the power/data connector from its clip and pulled through the 9V battery clip as well. I had no need for the alarm so I clipped the two white wires that are soldered to the piezo element (round metallic and white thing).

The screws to remove the circuit boards are fairly evident. The LED board is stuck to the case with what looks like hot melt glue. With a little encouragement this also comes away from the case.

A word of caution, when you remove the board that covers the buttons, take care that the buttons do not launch themselves into space. If not then like me you will

Spend some time picking them up from the kitchen floor. I especially kept the rotary switch that selects the house code so that I can refer to it when I come to solder the pads to select the house code that I want.

I now have the guts of the timer and the case. I dumped the case, screws and any other bits that I did not want to keep. I now have something that looks like this.

Looking at the face of the keyboard I saw a bunch of small metal buttons that are held in place by sticky tape. As I will be soldering new wires to each switch I can remove this keypad. The tape is quite sticky but will come away.

I noticed that when looking at the back of the keyboard that each keypad had one hole. For what I want to do I need two holes for each keypad so I used my trusty dremmel with a 1-1.5 mm bit to drill an additional hole for each keypad. I did this from the front to accurately place the drill. There is plenty of room at each keypad to do this.

I decided not to try and figure out how the chip and its connectors work which is the reason why I am soldering two wires to each pad. In essence I am duplicating the action of the switches that were removed.

Once all the holes are drilled, I tin the pads to be used, with solder. I am using Cat 5 pairs for each switch so I tinned the ends of each pair and then soldered these ends to the previously tinned pads, inserting the tinned ends of the pairs through the previously drilled holes. I sniped off any extra wire from the soldered ends.

I now have something that looks like this…

…and with all the pairs soldered, it looks like this…


Next I needed to set the house code. I’m happy enough to hard code this so I took the easy option and set the house code to A by holding the rotary switch to the pads and marking the pads that are connected to the switch. These I then soldered together. Pretty easy. Of course, this is the one part of the job that I did not take a picture of! If the house code needs to be selectable, It should be pretty easy to solder on additional pairs and hook these up to more switches.

OK, now the stressful bit. I plugged the timer guts into its power supply, plugged a lamp module into a mains socket (Set to A1) and shorted the ON wires for A1. Yay my lamp came on. Shorted the OFF wires and the lamp went off. Success! I then tested the remainder of the switches. Fine.

When powered up, the time flashes on the LED panel to indicate that the time is not set. This seems to cause no problem and as I did not make any connections for these switches, there’s not much I can do. I was not game to snip off the LED but perhaps for the next one I will de-solder.

I now have to house this unit in something that is functional and since hidden away, not necessarily pretty. I found a case in my office for a 6525 tape and decided that this would do. I drilled a number of holes for the cables and cut out a piece to accommodate the power/data connector and with my ever-ready hot melt glue gun, here is the result


I was concerned that the unit would generate some heat but after running it for several days, there was no noticeable heat generated, all the heat was at the wall wart end.

The Cat 5 pairs are terminated with terminal blocks. Here you can see the unit with the terminal blocks attached (Hot Melt) and each of the Cat 5 pairs connected into one side.

Next, I needed to connect this unit to node 0.2. This node is above the kitchen/utility room and really only controls the lights in these rooms. I have nodes 0.0, 0.2, 0.5 and 1.0 just now but more on those later. In node 0.2 I have 240V in, a number of electronic transformers that are connected to LV halogens and the necessary switching gear to make it all happen. Included in this switching gear are 4 lamp modules that have been modified a-la Future Flat and look like this.

I used a standard 2-gang surface pattress box cut to take the X10 units. The blanking plate had two holes cut into it to take safety fuses (Maplin), replacing the fuses in the original X10 units. Beneath the X10 switches are the two electronic transformers and below those, a terminal strip which connect the halogens to the transformers.

Power is provided from a ring main circuit and is isolated from the X10 units by the switches that you can see here.

Beside these two switches is another single gang box that provides the power to modified Mini Timer. I originally had all of this on the same ring as a number of older electronic transformers but the interference was such that I did not get a high X10 event success rate. I changed this so that the Mini Timer is on a separate ring to the switches and transformers and a filter, which clears up the interference, bridges these rings. My Home Controller PC is on the same ring as the Mini Timer and this is working with 100% success, to date.

I have two sets of (mains) multi-way switches, which currently switch the kitchen lights. I will replace my existing switches with momentary contact switches (pictures and description to follow) and will run cat 5 from the switches to the Timer unit, paralleled where necessary to simulate the same functionality as the multi-way switches.

When a switch is pressed, the appropriate switch on the Timer Unit is shorted and a X10 event is generated which will turn on the appropriate lights making this event pretty fast. My Home Controller (Mr House) will also pick this event up and change the status of the lights accordingly, which is a little slower.

The objective here is to keep the X10 switching as fast as possible with logging the events catching up later.

As you will probably know, the Mini Timer is capable of switching up to 8 devices. There is another switch on the Mini Timer that controls whether items 1-4 or 5-8 are active. I plan to use 1-4 as regular light switches with a key switch that will change control to 5-8. In this mode the X10 events will enable the alarm through 4 zone modes, which are Day, Night, Vacant and Pets.

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