Electronics question

[tres]

I have a battery powered light on the wall, simple mechanical switch on the side

I want to add Zigbee functionality to it to turn it on and off

I'd love some advice on the smallest possible solution to his, as hoping to incorporate it into the housing with the batteries.

Would something like this be viable, to also power off the batteries and solder in parallel with the switch, or am I looking in completely the wrong direction?

Thanks in advance clever people

 

[LuckyBenski]

That's designed for AC mains voltage. I'm guessing you want to run it on batteries still!

There are 2 main issues/problems to solve.

1. You want to switch this light on and off remotely. 1 option is a relay but they consume current. Maybe something solid state would use less energy to preserve battery life.

2. You want the device to stay on when turned on, but ZigBee being low energy, it only wants to power up briefly to send/receive a signal, change state, and power down again. Won't want to stay on indefinitely powering a relay.

Don't know what the right answer is off the top of my head but that might offer you some clues

 

[Rroff]

Maybe something solid state would use less energy to preserve battery life.

Personally I use optical relays/MOSFETs quite a bit - most often VO14642AT - but I build my own logic circuits around that using opamps, etc. which is where it gets a bit more involved if you have something which is triggered once on and off.

Though a BC557/547 transistor pair latching circuit isn't that difficult (personally prefer using a 555 or similar approach).

 

[tres]

That's designed for AC mains voltage. I'm guessing you want to run it on batteries still!

There are 2 main issues/problems to solve.

1. You want to switch this light on and off remotely. 1 option is a relay but they consume current. Maybe something solid state would use less energy to preserve battery life.

2. You want the device to stay on when turned on, but ZigBee being low energy, it only wants to power up briefly to send/receive a signal, change state, and power down again. Won't want to stay on indefinitely powering a relay.

Don't know what the right answer is off the top of my head but that might offer you some clues

Thanks very much, that's really useful

if the battery powered light in question was also IR remote controlled - and excuse my absolute lack of knowledge when it comes to these sort of things - could a zigbee switch trigger the light this way? That power up/briefly change a state to trigger the same whatever as an IR command would/power down etc?

 

[tres]

Personally I use optical relays/MOSFETs quite a bit - most often VO14642AT - but I build my own logic circuits around that using opamps, etc. which is where it gets a bit more involved if you have something which is triggered once on and off.

Though a BC557/547 transistor pair latching circuit isn't that difficult (personally prefer using a 555 or similar approach).

Thanks. I think all of that is completely over my head!!

 

[LuckyBenski]

Thanks very much, that's really useful

if the battery powered light in question was also IR remote controlled - and excuse my absolute lack of knowledge when it comes to these sort of things - could a zigbee switch trigger the light this way? That power up/briefly change a state to trigger the same whatever as an IR command would/power down etc?

Yes that could definitely work! It's a little bit adapter-on-an-adapter sort of thing, but there are ZigBee devices that can send IR signals too.

I actually thing Rroff's solution is the "right" one, but agree it could get a bit involved if you're unfamiliar. I'm an electronic engineer but haven't done a lot of that traditional transistor stuff, more digital/embedded e.g. Raspberry Pi and code.

I imagine you could find a small ZigBee module and circuit design for the matching transistor stuff, someone has likely solved this before, just need the right search terms.