Thread: Reusing components from circuit boards?

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OK I will start with a disclaimer.... I KNOW VERY LITTLE about computer related issues.

Now that is cleared up, on to my question. I found a circuit board in a tread mill the other day and it has 8 LED lights on it. What I was wondering is if I can unsolder the LEDs and reuse them. Also I was wondering about reusing the resistors. I have heard people mention doing something similar to this, but thought someone here might know.

OK the second question I pose is about using computer components to make current adapters. I saw a how-to one time about using the power converter on a computer as an adapter. If I can salvage the LED's I was wondering if then I can power them with the adapter. Or if someone has a way to reuse these components that would be better, I would greatly appreciate it.

This is very similar to the thread about using LED's in a skull in the how to section, but I didn't want to bog down that thread with my frugality.

OH one more disclaimer.... I know I can go to Radio Shack and buy these items but I think that it is so much more fun so salvage stuff. I have access to lots of circuit boards whether they are from computers, appliances, house hold items or other crazy stuff like tread mills so it would be really cool to reuse some of this stuff. Thanks in advance for any help!!!!



Here is the circuit board. The LED's are ate bottom.

Sure you can. Get yourself some Solder-wick or a solder vacuum (Soldapult) and go for it. If de-soldering IC's that are attached directly to the board, be sure to not overheat them. Use alligator clips as heat sinks if possible. Resistors can also be recycled the same way.

Originally Posted by Otaku

Sure you can. Get yourself some Solder-wick or a solder vacuum (Soldapult) and go for it. If de-soldering IC's that are attached directly to the board, be sure to not overheat them. Use alligator clips as heat sinks if possible. Resistors can also be recycled the same way.

How do I use alligator clips as heat syncs? Do I unsolder it from the back of the board or the front? Once I get the components I need, do I just solder them back together like they do in this L.E.D. eyes for Bucky thread? Or is there someway to wire them up with an adapter?

De-soldering is done from the back of the board. Use small clips so you can attach them to the leads (legs) on the IC you're removing. I usually do this with 2-3 legs at a time. Heat the solder until it melts then use the vac to pull the solder away. If you use copper wick place the wick on the solder then the soldering tip on the wick. Heat until the solder flows into the copper wick. Make sure that the lead(s) are completely free of the board before you try to remove the part or it may be damaged.

I'd just use the 9 volt battery snap for powering the LED eyes. It's cheap and the battery will last for many hours. I wouldn't worry about using an on-off switch unless you really want it.

That board in the pic is a resistor gold mine. Most boards nowadays use SMT resistors (very tiny) that are a pain to solder manually.

There are a couple of downsides to using salvaged LED's IMO. It's difficult to establish the component ratings as there aren't any labels on them. For example, LED's have forward voltage and current ratings which are used to determine the required resistor value to use with a given power supply voltage. The other issue is the leads are typically trimmed flush with the board, so you have very little to work with unless you plan on mounting them on another PC board. I learned a long time ago, it's just not worth trying to salvage this type of stuff - especially when you can pick up a hundred LED's off of Ebay forn under $5 shipped.

Mark

If anything I would look for components that are going to cost a descent amount if bought new to try and reuse. If I can pick up X component in a bag of 5 for $1 brand new, then I would have piece of mind that this component is probably going to work. At least a better chance then a used component. At least with my skill level, new to electronics, I don't feel that I have the experience to deal with used components.

Thanks bubbels that makes sense. I know that people can't really comprehend my frugality. I take great pride in the fact I make my own props and primarily use salvaged parts. I have learned that if I want to ask a question on a forum like this I need to take the good with the bad. Do you find that too being a novice with electronics? Its cool when you get great advice from someone like Otaku though. Thanks again Otaku by the way. Without him I wouldn't have known about the resistors on the board I found not really being used any more.

I also come across tons of relays and I mean lots of relays. So I am going to compile a list of them and see what people think I might be able to use.

Oh and one more question. Its more of a theory so I hope someone can tell me if I am wrong. Basically I am a complete beginner to all things electric and computer related and in my mind if i see a device has lights I assume that if I follow the path from the plug in the wall to the light that logically there would be the components I need to make the lights work on their own. So lets just take a hypothetical situation, say I have a tread mill that plugs into 110. If that tread mill plugs into 110 and there are LED's on the tread mill, am I wrong to assume that along that path there is not a voltage regulator that transfers the current for the existing LED's? Once again I will preface that I know nothing about such things I am just thinking out loud with the hopes there are people willing to impart some wisdom.

Absolutely.. I get some great idea, ask for opinions and the responses I get usually point me in some other direction. I know all about frugal pride. I worked construction during college, so I consider myself fairly skilled with wood. I am always finding super cheap ways to build things. My shelves out in the garage are made from an old computer desk. My new computer desk uses old dock legs I got for free. And I recently built 4 dvd shelves all from scrap wood.

Originally Posted by Bubbels

Absolutely.. I get some great idea, ask for opinions and the responses I get usually point me in some other direction. I know all about frugal pride. I worked construction during college, so I consider myself fairly skilled with wood. I am always finding super cheap ways to build things. My shelves out in the garage are made from an old computer desk. My new computer desk uses old dock legs I got for free. And I recently built 4 dvd shelves all from scrap wood.

Have you used any of that frugality for Halloween projects?