Wireless switch

[mytech]

Hi everyone.. i have wireless calling bell 433MHz freq.I wanted to trigger external circuit(Darlington to switch relay) using the receiver when the transmitter bell key is pressed instead of ringing.. also i wanted to take of the speaker.. then where can i get the trigger volt?..
Thanks..

 

[HarveyH42]

I bought some surplus($6 each) a couple months ago, but haven't gotten around to opening one up yet. Been using one to mess with the dog.

Figure there is a chip that generates the bell chime, was going to find the trigger pin there... Got me curious, so popped it open. The receiver portion is all descreets. Only chip is a 4069, hex inverter. Only bummer is that I don't think I have a relay that works off 3 volts.

 

[Hero999]

A Joule Thief style switcher might be able to make a 5V relay work at 3V.

 

[mytech]

I am getting 1.5v(+ive) from 2nd pin of IC and around .7v(+ive) from tone generator when the key is pressed..wat are the ways to amplify into 12v from external circuit with external power supply using this trigger except 555 monostable?..

 

[mytech]

@HarveyH42

Does your wireless bell contain diff. datas or same one?..
Because i brought 3 all has same freq. and data..

 

[HarveyH42]

They are all identical. Push any of the transmiters, and all receivers chime. The receivers have a variable cap and inductor with ferite slug, if the transmitters are similar descreets, should be able to alter the freq for different channels. Didn't do any measurements yet, got another project I'm trying to figure out what went wrong on.

I was going to just use an adjustable regulator and different batteries. A transistor should be good enough to drive a relay from there.

 

[mytech]

I got the perfect output to drive the relay.. it worked fine..
But i want to change the frequency..

Only one coil is available at transmitter as well as receiver, can i vary that or should i change the value of fixed capacitor?..,
I need to change the frequency or anything..

 

[HarveyH42]

I'm really not an RF guy, understand the basics, but getting more into it. Usually there is some way to adjust the frequency, but it's not a radical change. Really not sure if I'll get 4 seperate channels with these.

 

[mytech]

Thanks for your valuable infos. i il try if get the ans. i il inform. does anyone knows help me..

 

[Nigel Goodwin]

Adjust the coils! as simple as that.

 

[mytech]

But coil may need to match.. if i put the same cap. value at both the ends would be easy.. but i am not sure,, will it work when i change the cap?..

 

[Hero999]

The chances are the receivers aren't selective enough unless you want to alter the frequency a lot which might make it illegal.

 

[mytech]

The range is about 100 meter only.. so it wont be an illegal thing..
Whats the exact way to alter the frequency to get output...

 

[Hero999]

For a start it depends on where you live.

Here in the UK, it's illegal to transmit on most frequencies apart from 27MHz, 433MHz and 2.4GHz and 100m is close enough to interfere with your neighbour's radio so just shifting a couple of MHz could land you in trouble.

 

[mytech]

can we send any coded data using this module?..

 

[Hero999]

Not at any reasonable speed.

You could use mose code I supose.

 

[mytech]

I tested in scope its frequency is 310Mhz.. and i just added little to enormous value of inductor in parallel with the 15uh but the frequency doesnt change.. after connecting some more inductance also the receiver bell is ringing..
I didnt tested by changing cap.
Does anyone knows the solution for this?..
Also the whole information is below

http://www.talkingelectronics.com/projects/WirelessDoorbell/WirelessDoorbell.html