How to order parts for this circuit?

I'm a new to building circuits and trying to help my son with a school project.  Here is the circuit to hack the wireless doorbell into snail mail notifier (http://mimeproject.blogspot.com/2011/01/mail-notifier.html).  I'm lost here though it appears to be a simple circiut.

 (attached the circuit as image file)

Please help me with ordering parts and the proper sequence to solder them.

Thanks in advance.
- Al

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thousandeyes (author) 3 years ago

Hello ernestcraphead:

Thanks for taking time to provide detailed explanation. Will go to RadioShack later this evening to get the parts. Will update the post on the progress of the project.



G4224T3 years ago

The parts should be freely available from your local RadioShack store. The parts marked 1 & 2 in your diagram are actually 2 "blocks" from a standard IC. The blog details this as a 74HCT02N which is a quad 2 input NOR gate, IE it contains 4 of those blocks.

The other rectangular parts are resistors which should also be freely available. The values are not detailed on the blog but look like 10k resistors at the inputs and maybe??? a 1k at the LED. The actual values may need changing dependant upon the voltages / current you have on your doorbell.

When soldering, fit the resistors first and the LED. I would recommend using a 14pin DIL socket (again freely available) for the IC as soldering the IC directly can damage it.

I recreated the circuit in Fritzing to give you an idea of how to assemble it on breadboard, although i haven't tested it so you should check it. The battery pack is there just to show where power is connected, the actual power should come from your doorbell circuit.

Fritzing also created a schematic from the breadboard layout so I've included this as it may help you build it.

The circuit is basically a copy of the one you posted from the blog as far as i can tell. Whilst it will probably work ok it isn't really ideal. Unused inputs on the IC should be handled and the supply should be decoupled. Also make sure that the voltage at the input from the doorbell isn't actually higher than the voltage that supplies the circuit, neither of which should be higher than 5v.

Hope it helps anyway.

RS Flip Flop.jpgRS Flip Flop Sch.jpg
verence3 years ago

Would help to know where you live. US? India? Russia? Australia? Europe?

thousandeyes (author)  verence3 years ago

I live in US and have few Radioshack stores around me here.

thousandeyes (author) 3 years ago


nor-gate-flip-flop red.jpg