Here's an example using optoisolators. Its shown for just one switch, but is duplicated for the number of switches you have. I show a bulb as a load, but really, almost anything can be driven, given the ratings of the optoisolator are not exceeded.

 

That would be ideal. Is there a good place to buy them that's cheap? I'm trying not to spend to much money on this.

 

Here's an example using optoisolators. Its shown for just one switch, but is duplicated for the number of switches you have. I show a bulb as a load, but really, almost anything can be driven, given the ratings of the optoisolator are not exceeded.
View attachment 79099

Keep in mind that the grounds do NOT need to be connected between the two halves -- that's why it's called an opto-"isolator".

 

That would be ideal. Is there a good place to buy them that's cheap? I'm trying not to spend to much money on this.

Have you tried Googling "optoisolator"?

Right at the very top you see several sources that sell variants of the 4n35 for anywhere from 16 cents to a dollar or so.

DigiKey has them for as low as 43 cents in single quantities (under 9 cents each in quantities of 3000, which I'm guessing you're not interested in).

Mouser and Jameco are good places to look.

 

I'll take a look at that. Looks different from what I was thinking it was.

 

Keep in mind that the grounds do NOT need to be connected between the two halves -- that's why it's called an opto-"isolator".

Correct. Thanks for the clarification.

 

Ok that is a lot of choices.
Which type do I need?
Isolators - Gate Drivers (1060 items)
Optoisolators - Logic Output (2086 items)
Optoisolators - Transistor, Photovoltaic Output (9865 items)
Optoisolators - Triac, SCR Output (1523 items)
I found the original three chime wires that I belive when they are to make noise the wire that goes back to main board and closes the circuit to ground. So I need to put a meter to it and a voltage to see if it completes the circuit. I Tryed yesterday putting it to a ground though a meter and tripping a part that would make a sound and saw
zero voltage on the meter. I just don't want to send voltage where I shouldn't. So I'm hesitant to do so.

 

Which you choose depends on the loads you are driving. For example, I'd use Triac/SCR output to drive high voltage AC circuits. Logic Output would be when you are driving a microprocessor or digital circuit...

So when you measure the voltage, it would be a good thing to configure your meter so it also can measure the current drawn.

 

Ok found out the line from the power supply board was discontented so I re contented it and when each of the 3 chime wires are jumped to it I get 3 to 5 volts depending if I hold down the switch for that wire. Checked for current but did not see any. I have another meter that I know reads current. I'll look for it. I'm going to do a quick led jump and see if it lights up when I trigger it.

 

Do you know the different methods for reading voltage versus current?

 

That would be ideal. Is there a good place to buy them that's cheap? I'm trying not to spend to much money on this.

Most SMPSUs have at least one opto-coupler, TVs, VCRs etc sometimes have more for standby switching.

If you have kerbside recycling in your area, you might get enough totally free.

Another good place to look is PC modem cards - sometimes (if you're lucky) you get an AC input opto, more likely is the basic variety with a bridge rectifier in front of it - I've seen as many a 4 optos on a single PC card.

 

Ok to read current I have to have the flow pass though the meter vs voltage is just across two leads. And i rechecked the Voltage to discover the voltage max out at 9v. I put a led on the jump area and it lit up then blew. To much voltage. So is there a optisolator that will take 3 to 12v and work fine?

 

Ok to read current I have to have the flow pass though the meter vs voltage is just across two leads. And i rechecked the Voltage to discover the voltage max out at 9v. I put a led on the jump area and it lit up then blew. To much voltage. So is there a optisolator that will take 3 to 12v and work fine?

Its an IRLED inside the opto - you have to put a current limit resistor in series.

There's no shortage of online calculators for determining the resistor value to suit the Vcc.

 

Its an IRLED inside the opto - you have to put a current limit resistor in series.
There's no shortage of online calculators for determining the resistor value to suit the Vcc.

That's why my diagram included a resistor. To prevent the magic smoke from escaping.

 

That's why my diagram included a resistor. To prevent the magic smoke from escaping.

Thanks i

 

Ok I think I have it figured this out. If 9v is the source and the optoisolator is 1.5v at 20mA then I need a 1/2watt 390ohms resistor to make it a good 1.5v. Is this right? I'm thinking this optoisolator https://www.sparkfun.com/products/314
I just need 3 resistors and 3 optoisolators.

 

I agree with your calculations