motion sensor power supply problem

[wonderd]

I have a motion detector that uses 220V as input power supply, i need to use it with a 24V power supply.
it is made by Lynteck and the model is ES34.

Can anyone help please?

[wonderd]

I took pictures, do they help?

[LostViking]

I looked at the datasheet for this product on the manufacturers website. They didn't show any good information, but you can try contacting them directly with the question. I don't see any transformers in the pictures, but do see what looks like a full bridge rectifier. Although I find it hard to believe they use such a high voltage to run the thing. All PIR's I've ever used were powered by 24/48V's, some also used 12V.

Is there an external wall adapter or something?

[wonderd]

I tried searching for the datasheet too but with no luck.
no there is no adapter, only the three wires that you can see in the pictures, the blue and brown are the supply for this thing that you are supposed to connect directly to the power source.

[esp1]

hi,
The large blue capacitor is connected to the 'line' [phase] of the incoming mains supply.
The design uses the capacitive reactance of the cap to limit the current flowing that low value/hi-watt resistor.
You can work out the current flowing in the resistor, by using Xc= 1/ (2 *pi *  Freq * Cap)
Knowing your local mains supply 110Vac or 240Vac at 50/60HZ depending where you live.

The voltage across the resistor is connected to the FWB.

I traced thru a simliar device a few months ago, it takes less than 30 mins to produce a working sketch.
There are zener diodes and a sometimes a 5Vreg for the sensor chip.

Use the sketch to show you the best connection point on the pcb for your 24Vdc.

CAUTION: when connected to the mains supply the pcb and components are NOT isolated from the mains.

Lets know how you go, post your sketch if you need more help.

[waferstar]

I think that is easy to Change,and the left PCB is supply the power and for relay output.
and if you remove the compacitor and supply the AC current directly to the bridge circuit.

www.mcuservice.com

[wonderd]

I tried my best, does this make any sense?

[AN920]

I think it should trace out to be something like this. The 24VDC is further regulated down by another zener on the sensor pcb by the looks of it. You should be able to apply your 24VDC at the point indicated after removing Q1, or 24VAC  by removing C4 and making R3 small enough or short out (should have about 28VDC over C1) to have a regulated 24 VDC over C3

They may also run the relay coil positive direct from the unregulated DC, just after the rectifier. I have seen both methods used. In this case the zener may only regulate the output voltage to 12VDC and not 24VDC

[wonderd]

At the end, the solution i chose was the simplest and took me 5 minutes to get there. First i had to fix my drawing with the help of one of my co-workers that knows his way around electronics.
Then if you follow the red line on the bottom - you will see what i did.
Now the whole thing works using 220V, but the relay is providing dry contact and not passing 220V as it did before, so now i can connect it to my water computer in the yard and every time the dog comes to the lawn to dig, the sprinklers make sure she won't