How to wire a momentary switch as a 5-12v power button

[Basement_Modder]

THIS WILL WORK FOR ANYTHING BETWEEN 5-12v!
NOT JUST 7.4v!


Daftmike is doing this on his N64p. it was lost.
This is fairly-simple, and could give your portable that extra "flair" in the compo. Just follow the diagram exactly.

 

[daftmike]

Re: How to wire a SPST momentary switch as a power button

hmm...looks familiar

 

[Basement_Modder]

Re: How to wire a SPST momentary switch as a power button

hmm...looks familiar

Daftmike is doing this for his N64p

 

[daftmike]

Re: How to wire a SPST momentary switch as a power button

Just pointing out that it's a little rude to post a circuit I designed without my permission or giving proper credit.

Also you should only "follow the diagram exactly" when drawing around an amp from a 7.4v supply, some of the component values would need to be tweaked for other applications.

 

[Basement_Modder]

Re: How to wire a SPST momentary switch as a power button

Crap, I uploaded the wrong one. The final has credits to you in it. Will fix right now.

 

[daftmike]

Re: How to wire a momentary switch as a 7.4v power button

It's no big deal, I haven't got a problem with my work being posted here and I don't want it removed, there's no hard feelings or anything.

But in this case if I was asked beforehand I could have cleaned up my diagram a bit and written some proper instructions.
It's been taken out of context, I posted it as an aside in my wip thread and didn't intend it to be used in a reference style post.

The op copied it verbatim from my drawing and it's clear he hasn't made the circuit and wouldn't be able to help anyone if they tried it and ran into problems.

Connect the battery to the left-hand side and the load on the right.
Pressing the switch will turn the circuit on, pressing again will turn it off, after switching off there is a delay of about 2 seconds whilst C1 charges before you can switch on again
The transistors can be changed for equivalents, Q1 can be any low-power NPN (2N2222A, 2N904, BC337 etc.) Q2 can be almost any N-channel MOSEFT (IRF530, IRFZ44, STP36, BUZ71 etc.)

There's no practical advantage, it's purely aesthetic, I made the circuit so I wouldn't have a large ugly slide switch on the outside of my portable, hopefully giving it a cleaner appearance.

 

[Basement_Modder]

Re: How to wire a momentary switch as a 7.4v power button

I am going to do this in my portable; was just hoping to keep that hushed as its one of my "surprises."

Sorry for any hard feelings.

 

[daftmike]

Re: How to wire a momentary switch as a 7.4v power button

No worries, If you have any problems with the circuit or selecting components or anything just ask and I'll try to help you out.

 

[Basement_Modder]

Re: How to wire a momentary switch as a 7.4v power button

Thanks.

 

[snowpenguin]

Re: How to wire a momentary switch as a 7.4v power button

BUMP!

I need some help with this.

First- will this only work with 7.4v, or can I use different voltages, if so what range?

And since I'm don't know much about components, can somebody recommend a transistor from radioshack that will do the job of Q1?

 

[daftmike]

Re: How to wire a momentary switch as a 7.4v power button

The circuit should work fine as-is for 5-12V, the resistors may need tweaking a bit for voltages outside that range.
Q1 is any regular low-power NPN transistor such as this one.

 

[snowpenguin]

Re: How to wire a momentary switch as a 7.4v power button

Yay!

Kthxbai

 

[Basement_Modder]

Re: How to wire a momentary switch as a 7.4v power button

The circuit should work fine as-is for 5-12V, the resistors may need tweaking a bit for voltages outside that range.
Q1 is any regular low-power NPN transistor such as this one.

Wait-so this will work on 11.1v batteries? Sweet! Imma do this in my GCp now if I have room! <3

 

[snowpenguin]

Re: How to wire a momentary switch as a 7.4v power button

And a quick dumb question, what value is 4m7? 4 million and what, 700,000, 70,000, 7,000, 700, 70, 7?

 

[Argelfraster]

Re: How to wire a momentary switch as a 7.4v power button

A little off topic, but Daftmike, are you going to finish that N64 portable?

 

[snowpenguin]

Re: How to wire a momentary switch as a 7.4v power button

And also, is it ok to use a .1 uF cap in place of the .22 uF? Dang radioshack didn't have any .22.

 

[daftmike]

Re: How to wire a momentary switch as a 7.4v power button

@snowpenguin
4m7 = 4,700,000Ω and no, but you could put two 0.1uF caps in parallel to make 0.2uF, which is close enough.

@argelfraster
it all got lost a while ago when i moved house, along with all my games and spares

 

[snowpenguin]

Re: How to wire a momentary switch as a 7.4v power button

Damit Dangit Dangit, I got the last 2 pack of .1 uFs they had as well.

 

[eurddrue]

Re: How to wire a momentary switch as a 7.4v power button

Damit Dangit Dangit, I got the last 2 pack of .1 uFs they had as well.

And he said that would work...:S

 

[Basement_Modder]

Re: How to wire a momentary switch as a 7.4v power button

Damit Dangit Dangit, I got the last 2 pack of .1 uFs they had as well.

And he said that would work...:S

But if you look at the schematics you'll see that if he uses only .1uf caps, he will need 3 of them. :S

@snow- ask at the desk. At my ratshack, they only have 2 packs of most components in the drawers at one time, but they usually have a ton in the stockroom.