Bye Bye Standby make a great range of home automation plugs and switches, but their one major gap is a decent light switch. This instructable will show you how to improve their on-off ceiling switch to make it compatible with regular light switches.
The on-off ceiling switch is a great switch because unlike the many dimming switches out there, this one is straight on/off with a relay, so is compatible with energy saving lightbulbs. The problem with the switch is that it defaults to Off, so when you first power it up, the light is off and you need to find a remote to turn it on. That's OK for the householder who is familiar with it, but not OK for the visitor to the house who cannot work out why the light won't work. A better configuration would have been to have the switch default to on so that your light can behave just like a normal switched light, with a remote override when you want it.
That means the behaviour is now;
Turn on at the wall - light goes on
Turn off at the wall - light goes off
Turn on at the wall and turn off with the remote - light goes off
On at the wall/off with with remote - turns on with the remote, or turns on at the wall by turning off then on again.
The last step isn't perfect, but it's a darn sight better than always off.
WARNING: It should go without saying, but this project involves modifying a switch for mains electricity in a way that the manufacturer does not support. Only attempt it if you are happy with modifying electronics. Also, it will of course invalidate your warranty, but if you didn't figure that out, you really shouldn't be doing this!
Step 1: What You Will Need
Step 2: Crack Open the Switch
Unfortunately the switch is glued closed, not screwed, so you are going to need to use some force to open it. Apply a screwdriver to the edge of the join and push until you hear it snap open the glue. Do this all the way round. This will open the switch. If you are careful you will preserve the small clips that can hold it closed, but don't worry if it snaps them, because we are going to glue it back together in the end anyway.
Step 3: Take Out the Old Relay
The relay is the big black box at the edge of the switch. It should be obvious where it's connectors are, but look at the second picture for a diagram. Desolder them to take the relay off. Take care not to touch anything else, and to not melt the big grey rotary switches that go very near to one of the terminals.
Step 4: Insert the New Relay
The new relay doesn't quite slot straight in. First of all you need to snap of the leg that is the default open one - we don't need that and it just gets in the way. Looking at the pins with the two pins at the top and three at the bottom, you snap off the bottom left one, keeping the top two and the bottom right and bottom middle one.
You then need to add a new hole to the circuit board. Drill a 1mm hole just above the original one for the new default-on pin to go.
Solder the new relay in, bridging the gap to the new pin with solder.
Step 5: Re-assemble the Case
Since the relay is ever so slightly longer than the original, you will have to bend the fuse leads slightly to get the fuse out of the way of the contacts, but as you can see, there is enough give in there to do that.
Put a couple of drops of superglue on the case and put the lid back on. Now you have a default-on bye bye standby switch. Wire it up in the ceiling as described in the manufacturer's instructions.