Anyone Know How To Make A Touch Contact Switch?

[Sir_Lawrence]

I'm trying to find out how to make a switch witch is activated just by touching the contacts. Using this type of switch would solve the problem of the mod being activated by laying it down on a pushbutton switch. The Bartleby mod uses this kind of switch. Any links, parts list, or diagrams would be greatly appreciated.
Thank you

 

[FizzleFisch]

I'm trying to find out how to make a switch witch is activated just by touching the contacts. Using this type of switch would solve the problem of the mod being activated by laying it down on a pushbutton switch. The Bartleby mod uses this kind of switch. Any links, parts list, or diagrams would be greatly appreciated.
Thank you

hmm ...didn't realize the Bartleby used a touch-switch. Are you sure?

..wonder what mosfet & charge ic it's got.

 

[wingerlight]

This is a circuit I found for a touch switch. Hope this helps ya.

 

[cybervex]

A master on/off switch also solves the problem of a box mod firing when laying on the button.

The problem with the touch switch is that dry skin tends to not work well.

 

[Sir_Lawrence]

I know, but it has now become my quest to make a mod with a contact finger switch. I just think it is cool. But I know nothing about schematics, electronics, and so forth. I need common sense drawing of the connections with an exact parts list. I guess I'll just keep looking. Like when I post about how to make 5v mods... I show every little detail and try to answer every question that people have so they can make their own mods.

 

[cybervex]

The touch switch can be made with the the design that wingerlight posted

I would use a IRF8736 MOSFET and a surface mount 4.7M OHM resistor. Can be purchased from Newark or Digi-key for a total <$1 plus shipping which is very amusing at 5 time the cost of the parts.

The circuit board will be a little more difficult. copper clad board from radioshack along with some ferric chloride. YouTube has many videos on etching circuit boards. Laser toner printed on magazine paper then ironned onto the copper clad board works fantastic depending how small you are planning to make the traces.

cadsoft has free circuit design software.

 

[Sir_Lawrence]

The touch switch can be made with the the design that wingerlight posted

I would use a IRF8736 MOSFET and a surface mount 4.7M OHM resistor. Can be purchased from Newark or Digi-key for a total <$1 plus shipping which is very amusing at 5 time the cost of the parts.

The circuit board will be a little more difficult. copper clad board from radioshack along with some ferric chloride. YouTube has many videos on etching circuit boards. Laser toner printed on magazine paper then ironned onto the copper clad board works fantastic depending how small you are planning to make the traces.

cadsoft has free circuit design software.

Thank you. I will give this a try.

 

[Sir_Lawrence]

The only problem is that I don't know what pins on the mosfet to hook up to where. What I need is a drawing... one day I'll get the hang of this stuff!

 

[WillyB]

Keep searching these forums, touch switches have been discussed many times. Most though have abandoned the idea.

Here's something to get you started. Sorry I forgot whose work it is to give proper credit.

 

[MastiffMike]

Some interesting stuff here:
Tapeswitch Corporation - Safety, sensing, and signaling products

And sized about right for mods:
Tapeswitch Corp. Online Store

 

[AmplexorJ]

To answer your question, Yes, I know how to make a contact switch.

 

[MastiffMike]

To answer your question, Yes, I know how to make a contact switch.

I see you read the thread title but failed to read the original post that goes with it!

 

[Sir_Lawrence]

To answer your question, Yes, I know how to make a contact switch.

I'm glad you know how to make one. Would you care to share with everyone how you do it?

 

[Scubabatdan]

Hows this look, help any? It is one I have have ordered parts for.
First one is without a voltage regulator.
Second is with a voltage regulator.
Dan

 

[Sir_Lawrence]

Hows this look, help any? It is one I have have ordered parts for.
First one is without a voltage regulator.
Second is with a voltage regulator.
Dan

That looks great! Thank you. The 100K and 470R are just resistors? Where did you order the parts from? I looked at Digi-Key and they don't have the BC109C... And the 2n3055 is kinda large (and expensive). Eybervex suggests using the IRF8736 mosfet. I think that is what he uses in his Bartleby 5v mod. But, I don't know how to wire that. If you could help, that would be great... showing me what pins go to where!
Thanks

 

[Scubabatdan]

That looks great! Thank you. The 100K and 470R are just resistors? Where did you order the parts from? I looked at Digi-Key and they don't have the BC109C... And the 2n3055 is kinda large (and expensive). Eybervex suggests using the IRF8736 mosfet. I think that is what he uses in his Bartleby 5v mod. But, I don't know how to wire that. If you could help, that would be great... showing me what pins go to where!
Thanks

Well I was actually leaning toward 2 BC548's As these will handle up to 30vdc and they are smaller transistors. Yes the 100k and 470R are just resistors. I found them at Futurlec, The Electronic Components and Semiconductor Superstore
I will Have to look up the IRF8736, havent used one.
Oh and I found them here:
BC548 Datasheet

BTW here are circuit board schematics:
Dan

 

[5cardstud]

There was one posted on here earlier today.

 

[Sir_Lawrence]

Well I was actually leaning toward 2 BC548's As these will handle up to 30vdc and they are smaller transistors. Yes the 100k and 470R are just resistors. I found them at Futurlec, The Electronic Components and Semiconductor Superstore
I will Have to look up the IRF8736, havent used one.
Oh and I found them here:
BC548 Datasheet

BTW here are circuit board schematics:
Dan

So, just use 2 BC548's instead of the diagram you first showed? I went to their site, and they are really cheap! And this will work for 3.7v, 6v, and 7.2v with or without a regulator? This seems to be the way to go since they are so small!
Thanks

 

[Scubabatdan]

So, just use 2 BC548's instead of the diagram you first showed? I went to their site, and they are really cheap! And this will work for 3.7v, 6v, and 7.2v with or without a regulator? This seems to be the way to go since they are so small!
Thanks

The first one is without a regulator good for 3.7vdc, second is with the regulator for 6+vdc. Use the BC548's instead of the BC109C and the 2N3055. I have not tested these that is what is in the mail comming here.
My first try too
Dan

 

[Sir_Lawrence]

The first one is without a regulator good for 3.7vdc, second is with the regulator for 6+vdc. Use the BC548's instead of the BC109C and the 2N3055. I have not tested these that is what is in the mail comming here.
My first try too
Dan

Thanks again for your help. I'm going to have to order these this week.