Help with simple project (Big Newbie here)

R!f@@

Joined Apr 2, 2009
9,918
The relay is to use instead of the FET since u don't have DMM.

I donno how the switch is wired, and without tht info u cannot trigger the device. To use the mosfet a common point should be there. If the switch has ground terminal used as connection then u can use a cheap transistor instead of expensive FET to trigger.

I asked for a relay cause this way u do not have to worry about the interconnection what so ever. it is isolated and works 100% guaranteed.

The relay will just click and will not drain the li-on any sooner than a mosfet. U wouldn't know the difference.
Besides using the relay makes everything really simple.

One more thing, my ckt will use less parts and will be easier to built. I do not a regulator either
 

Thread Starter

Rob1132

Joined Nov 4, 2010
36
Thanks for all the help everyone. I think I'm going to read up on everything a little more before I attempt to put this all together. I'll post back if I ever get it going.
 

Thread Starter

Rob1132

Joined Nov 4, 2010
36
Ok, well it's been about 2 months and I'm just no good at this. I followed Otaku's diagram and put everything together, but it doesn't work. It might just be that I'm not good soldering, but at this point I'm wondering where I can get professional help with this. I've looked around locally, but I can't find anything. Does anyone know of any web sites that might build these things for me?
 

R!f@@

Joined Apr 2, 2009
9,918
I dunno about websites but I think you might find someone here that lives near you. Give it time and you'll see.
 

thatoneguy

Joined Feb 19, 2009
6,359
Ok, well it's been about 2 months and I'm just no good at this. I followed Otaku's diagram and put everything together, but it doesn't work. It might just be that I'm not good soldering, but at this point I'm wondering where I can get professional help with this. I've looked around locally, but I can't find anything. Does anyone know of any web sites that might build these things for me?
Where do you live?

Several here like building projects, problem being, there's only so many projects one can build, so making a new one with the parts paid for is fun!
 

wayneh

Joined Sep 9, 2010
17,496
I've seen lots of Halloween novelties that say funny/creepy things when a Trick-or-Treater's hand approaches the candy bowl. IF (big if) there was a way to hijack the audio and replace it with something of your choosing, is that what you're trying to achieve?

Oops, I think I just went from page 1 to here without reading the history. Sorry.
 

thatoneguy

Joined Feb 19, 2009
6,359
I've seen lots of Halloween novelties that say funny/creepy things when a Trick-or-Treater's hand approaches the candy bowl. IF (big if) there was a way to hijack the audio and replace it with something of your choosing, is that what you're trying to achieve?

Oops, I think I just went from page 1 to here without reading the history. Sorry.
You just volunteered. :D
 

Thread Starter

Rob1132

Joined Nov 4, 2010
36
I live around the Buffalo, NY area. I thought I was actually going to get the thing to work on my own, but I think it didn't work because I had a hard time soldering. I'm not experienced with that and some of the parts required multiple wires soldered to one pin and there's probably some that accidentally over-lapped or something.
 

Thread Starter

Rob1132

Joined Nov 4, 2010
36
Ok, I actually finally finished this and got it to work! Thanks to everyone who helped. My problem the first time was that my soldering was so poor that a few connections got soldered together. After buying a third hand it made that problem much easier to avoid the second time I tried it.

I'm going to build this project again, but add a 9v battery clip/case with an on/off switch next time. I was sorting through all the parts to buy again and it looks like radio shack no longer carries the LM7805 voltage regulator. I found someone on ebay selling some LM7805C regulators, but I'm not sure if that would work. Does anyone know if there's a difference or is it just more of the model number?

http://cgi.ebay.com/iTM-LM7805C-5V-...932?pt=LH_DefaultDomain_0&hash=item5acf623acc
 

Audioguru

Joined Dec 20, 2007
11,248
I had a hard time soldering. I'm not experienced with that and some of the parts required multiple wires soldered to one pin.
We use a printed circuit board or stripboard where each hole has only one wire or one wire of a part. The printed wiring joins the parts together so there is never more than one wire in a hole. Sometimes jumper wires are used to join parts together but there is never more than one wire in a hole.
I use masking tape to hold wires on a circuit board for me to solder them.
 

wayneh

Joined Sep 9, 2010
17,496
I was sorting through all the parts to buy again and it looks like radio shack no longer carries the LM7805 voltage regulator. I found someone on ebay selling some LM7805C regulators, but I'm not sure if that would work. Does anyone know if there's a difference or is it just more of the model number?
Surprising the Shack would drop that one. The e-Bay regulators are probably fine. Personally, I've had very good luck with cheap parts out of Asian sellers on e-bay. But maybe I should emphasize LUCK, because there are plenty of horror stories from others here. And I'd be reluctant to buy 50 of anything from an unknown seller. I'd look for 5-10 and see how it goes.
 

Audioguru

Joined Dec 20, 2007
11,248
Don't buy cheap Chinese junk (fakes) on E-Bay. Buy guaranteed parts from a real electronics parts distributor in your own country.
 

Thread Starter

Rob1132

Joined Nov 4, 2010
36
Yeah one of the first things I do when I search for anything on ebay is to click on the "North America only" tab. The lot of 50 regulators is actually coming from Colorado. It's the only place I've been able to find the 7805's so far.
 

wayneh

Joined Sep 9, 2010
17,496
Yeah one of the first things I do when I search for anything on ebay is to click on the "North America only" tab. The lot of 50 regulators is actually coming from Colorado. It's the only place I've been able to find the 7805's so far.
I'll bet you those came from his supplier in Hong Kong, which would be happy to sell to you directly. Buy low, sell high.
 
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