Touch activated Switches

[killivolt]

What Voltage do you want me to used for the relay. Can I use the V+ I'm using for the circuit or do I have to step it down.

What is the Ideal Voltage.

Edit Edit: Oops I got the wrong one / rated 60v

Looking at the Chart it was up to 15v so I'll just use the 12v supply line.

By the way... Thanks for all the help.

kv

 

[Roff]

What is the nominal voltage rating of your relay coil?

 

[killivolt]

What is the nominal voltage rating of your relay coil?

I haven't picked one yet.

Edit: I'm currently pulling a 5v line down and activating another relay. In effect this momentary contact relay we are talking about will pull the 5v down for me instead of using momentary contact switch that an Operator is doing with a hand held switch.

Edit:Edit: Any suggestions would be great.

 

[Roff]

I haven't picked one yet.

Edit: I'm currently pulling a 5v line down and activating another relay. In effect this momentary contact relay will pull the 5v down for me instead of using momentary contact switch that an Operator is doing with a hand held switch..

I don't understand what you mean.

If you intend to try this scheme, by all means test it, with the lengths of wire you intend to use, before you install it permanently!

 

[killivolt]

I don't understand what you mean.

If you intend to try this scheme, by all means test it, with the lengths of wire you intend to use, before you install it permanently!

Simple the wire is there already I will first get the circuit running on my bench then integrate it to the existing wire that I've already installed.

I was going to put in some Tactile switches but, I think this would be a good way of stopping the abuse and limit accidental firing of the circuit.

Edit: Sorry about the confusion.

 

[Roff]

You need two wires. Are they both in place?

 

[killivolt]

You need two wires. Are they both in place?

Yes. I have installed a wire with 4 conductors.

 

[Space Varmint]

Where will it be added if needed. In the one shot or on the D junction of the MOSFET?

Edit: I think I understand. I need to Amp the 5v line on the Drain.

The transistor amp would be in between the FET & the one shot if needed. I think I would put some resistance in the Drain circuit. Maybe 10K or more. I don't know what your relay is like. If it is low power then the one shot should drive it.

 

[Mr RB]

I think you can just use the remote receiver part of the circuit as the touch switches. There is probably plenty of room noise especially if there are fluorescent lights, I have done touch switches that are basically just a NPN transistor with a floating base (or 1megohm trimpot on the base). Touching the base will turn the transistor on fine with no need for an external "exciter".

 

[killivolt]

I think you can just use the remote receiver part of the circuit as the touch switches. There is probably plenty of room noise especially if there are fluorescent lights, I have done touch switches that are basically just a NPN transistor with a floating base (or 1megohm trimpot on the base). Touching the base will turn the transistor on fine with no need for an external "exciter".

I this what you had in mind ?

Edit: If possible I have that 5v coming from a 2n3907 and I need to pull it to ground with a single pulse in turn I have software that will read zero and mute some microphones in the room. A second pulse will un-mute.

Edit:Edit: I have put this on the power supply and measured the Emitter 1.9v with a 5v supply on the collector. I put 1megohm on the base and touched it droping the voltage to 0.6v on the emitter.

My thinking was wrong. It will not work with the 5v supply from the 2n3907 pulling it to ground as I thought. Instaead it would be a constant drain 1.9v until touched then it would drop the voltage to 0.6v.

 

[Space Varmint]

I this what you had in mind ?

Edit: If possible I have that 5v coming from a 2n3907 and I need to pull it to ground with a single pulse in turn I have software that will read zero and mute some microphones in the room. A second pulse will un-mute.

I would stick with the FETs because of the high Z which makes it very sensitive. You can always strap it down with some resistance if the fluorescent lights set it off.

 

[Mr RB]

I this what you had in mind ?

Edit: If possible I have that 5v coming from a 2n3907 and I need to pull it to ground with a single pulse in turn I have software that will read zero and mute some microphones in the room. A second pulse will un-mute.

Edit:Edit: I have put this on the power supply and measured the Emitter 1.9v with a 5v supply on the collector. I put 1megohm on the base and touched it droping the voltage to 0.6v.

My thinking was wrong. It will not work with the 5v supply from the 2n3907 pulling it to ground as I thought. Instaead it would be a constant drain 1.9v until touched then it would drop the voltage to 0.6v.

Close. You put the 1Mohm pot to ground, keeps the transistor turned off until you touch it. You would also need a pullup resistor say 1k on the collector to 5v then take the output signal from the collector.

 

[Space Varmint]

I agree with 1Meg to ground on base or gate but I would start with 10K or higher on collector.

 

[killivolt]

I have a question where is the frequency coming from in this?

I'm guessing it's the way A1 / (1-2)(3-4) are being influenced by the 9v,470k,27k,10k,470pf.

The arrangement allows it to invert at that frequency or something.

 

[Space Varmint]

The 20KHz? The oscillator. That's a square wave relaxation oscillator. It's held by the RC time constant. When the capacitor charges up through the resistor, the gate turns and turns the other off until it charges up again.

 

[killivolt]

The 20KHz? The oscillator. That's a square wave relaxation oscillator. It's held by the RC time constant. When the capacitor charges up through the resistor, the gate turns and turns the other off until it charges up again.

So, it's just dropping the signal to 0 then back up at 20khz.


Thanks.

Edit: In that way the sign is cut out. This is to mimc AC type of oscillation "Roff" was talking about in the beginning.

 

[killivolt]

I received approval for the parts. One problem I didn't look closely at what I needed I didn't pick up a 680pf capacitor.

I don't want to go back to get a single capacitor or get a bunch of them I probably won't use. So, I thought maybe I could either connect them in series or parallel out of the bunch I do have hoping to get close enough, or do I just get the right Capacitor and stop trying to fool the circuit.


kv

Edit: I have a bunch of tv circuit boards but haven't had any luck finding one. I'm wondering what other devices might have one say computers or VCR's , Hand held devices ?

kv

 

[Roff]

I received approval for the parts. One problem I didn't look closely at what I needed I didn't pick up a 680pf capacitor.

I don't want to go back to get a single capacitor or get a bunch of them I probably won't use. So, I thought maybe I could either connect them in series or parallel out of the bunch I do have hoping to get close enough, or do I just get the right Capacitor and stop trying to fool the circuit.


kv

Edit: I have a bunch of tv circuit boards but haven't had any luck finding one. I'm wondering what other devices might have one say computers or VCR's , Hand held devices ?

kv

I don't see a 680pF cap in the schematic. Am I just missing it?

 

[killivolt]

I don't see a 680pF cap in the schematic. Am I just missing it?

As I looked at it on top the 4069 connecting the 2 series busses bridging both.

 

[Roff]

I missed that. A larger value will give you slower rise and fall times on the output. A smaller value will, of course, give you faster rise and fall times.