So many years ago I bought a RC-029 remote control power hub which I used to control some AC lights in my old bachelor apartment I used to live in. It was a pretty simple unit. It came with one remote that had two buttons on it; an "ON" button and an "OFF" button. There were a couple things I disliked about this unit though. One being the fact that there was only one channel to control, and the other being that the remote required a strange A23 12V battery which was hard to find and fairly expensive. Not to mention it also didn't last very long. After a while I eventually stopped using this system and tossed it in my junk bin and forgot about it.
Fast forward almost 4 years later and my brother bought me a INSMA 4 channel remote control switch for Christmas. It had 4 channels which control 4 individual relays, and came with two remotes which both used a fairly common coin cell battery. The only catch with this unit is that you have to be fairly comfortable with wiring up relays and be able to find an appropriate power source since it didn't come with one which wasn't a problem in my case.
When I first hooked it up I used channel A to control a 120VAC light above my couch, I used channel B to control a 12VDC set of lights in my glass cabinet and I used channel C to control a small LED strip at my desk. Both the led lights on channel B and channel C shared the same high current 12VDC voltage source. I tried powering the INSMA switch as well with the same voltage source but I ran into issues where the unit kept resetting. I suspect when it shared the same power rail as the relays, the back emf upset the rest of the circuit causing it to reset. For this reason I ended up finding an old 12VDC adaptor to power it separately and that seemed to do the trick.
I used the system like this for months and scratched my head trying to figure out what to control with channel D. It wasn't until fairly recently when I had installed some hanging lamps in my kitchen I thought that it would be great to be able to control them with that last channel. The only problem though was that these new lights were on the opposite end of my condo from here I had the switch located. I thought it would be a pain to route wires all the way from switch to the kitchen where the lamps were installed.
After some thought, I realized I still had the older RC-029 powered hub sitting unused in my junk bin. I thought this would be a great way to repurpose it so I could avoid the wire routing. The plan was to open up the old RC-029 remote, solder wires across the buttons and connect them to relay channel D on the switch powering both using the same 12VDC source.
To control the two buttons on the RC-029 remote I only needed to solder 3 jumper wires since both of the buttons share a common connection. My first plan was to connect these jumper wires directly to the relay and make use of the fact that it is a SPDT relay. Since the RC-029 remote only transmits an RF signal when a button is pushed, wiring it in this way meant that it the remote would always be transmitting. I figured this wouldn't cause any interference issues with the switch since it operates on different frequency however that was not the case. I found every time that every time the RC-029 was transmitting(which was all the time), the switch could not receive any signals. After ruling out any power supply issues I decided to look at the signals using a SDR USB dongle to see if the RC-029 created any interference in the frequency range the switch was working at but couldnt seem to find any.
In the end I decided to make an adaptor board to connect in between the RC-029 remote and the switch.
Below is the complete system diagram with the adaptor board.
The purpose of the adaptor board is to only "press" the ON or OFF button to the RC-029 remote for a second or so when the relay on the INSMA switch makes a change. There are a couple different ways I could of designed this board by creating a 1 shot pulse using a 555 timer or something but I wanted to find a way to do this with the least amount of components possible.
What I ended up doing was using a 1000uF capacitor to provide a brief burst of current to the LED of an opto-isolated mosfet . Once the cap is full the current is then limited fully by the 100k resistor and the 1k which isn't enough to keep the opto-isolator on. The 1k resistor limits the max current going to the LED and the 100K resistor discharges the capacitor when the circuit is off. I had to be careful about choosing the value of the discharge resistor. I wanted it to be low enough to discharge the cap as fast as possible but I also didn't want it to be so low that the LED stays on at all times.
In the end I put the whole thing in a Blue Label whiskey box. I didn't feel like putting a whole lot of work into an enclosure for this(clearly). I just needed something to keep the wires out of sight and I think this worked great.
I know there are more advanced wireless systems out there you can buy that have multiple channels and multiple base stations that allow you to wirelessly control outlets from all different parts of your home but I wanted to make use of the parts I had. These days we live in a throw away society where we simply get rid of what we have and buy the latest and greatest to suit our needs but if I'm able to modify something old to make it do the same thing I get much more satisfaction.