Minimum tools for DIY electronics

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basicchip
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Minimum tools for DIY electronics

Post by basicchip » Fri Jun 07, 2013 12:02 am

I'm often asked what kind of tools do you need to do electronics. While I've been doing this a long time and have been accumulating test equipment over the last 25 years the answer can be surprisingly simple.

This is part of my lab bench (note -- wine glass required; it was after 5) --
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Obviously I have my pick of the tools, it helps when your business is electronics consulting.

But there are a couple tools, that I'd be lost without.

The first is a logic probe. Back in the dark ages I worked for HP and acquired one of their logic probes, like all HP gear from that era a marvelous design. Those are long since gone from the catalog, and when mine gave up after 20 years I was about to go build a PCB for one. But first I decided, better google it, and yes you still can buy logic probes and they are less than $20. I picked up one from Elenco. Not the fanciest in the world, but it shows high low and toggling signals. But it came with a couple alligator clips to supply power. Wow, how crude. Now a days there is a USB port within 10 meters of any spot in the US it seems. So I grabbed a USB cable, snip snip, wired the power leads to replace the alligator clips soldered it together. Added a cable tie for strain relief.

Walla, instant portable logic probe.
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While a scope is great, lots of time all you need to figure out is --
  • Is that line high or low?
    is power connected?
    is ground connected?



basicchip
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Re: Minimum tools for DIY electronics

Post by basicchip » Fri Jun 07, 2013 12:11 am

Next on my list is a continuity tester. It comes in handy when that signal isn't doing what you expect. You need to know if it is connected.

The old beeper lights are OK, and I still have a couple of those. Why the continuity lights are called ""beepers" too is interesting, maybe they are wishing they were audible as well.

But the audible ones are best. Some meters have this built in, but meters are a bit clunky and the pen type are most useful.

If you can find an obsolete LM3909 a couple wires and components make a great pen beeper. Halted in Sunnyvale still has them http://www.halted.com While $5 seems like a lot for an obsolete part, it is still cheaper than building the discreet transistor version, though I may do that someday with leftover SOT-23 transistors from the original ARMexpress.
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I built this one with perf board using the carcass of a beeper light. Believe me when one of the internal wires broke, I was lost until I could figure out where it was suppose to go. So now I've posted the spec sheet and schematic here so I'll be able to find it 5 years from now when I need it again.
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The components laid out
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And the assembled beeper. The obvious advantage of the audible one is you can keep looking at the PCB while you are checking continuity. Also you will get different tones depending on whether there is a small resistance or diode rather than 0 ohms.
Attachments
LM3909.PDF
Full data sheet for LM3909
(149.25 KiB) Downloaded 403 times

basicchip
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Re: Minimum tools for DIY electronics

Post by basicchip » Fri Jun 07, 2013 12:13 am

Next on the list is a meter. While Flukes are great, most of the time the $5 ones from Harbor Freight are perfectly fine. I have at least 4 of them around the bench and garage because they are so small they get lost under a pile of paper when I need one.
meter.jpg
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They often go on sale for $4

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Re: Minimum tools for DIY electronics

Post by basicchip » Fri Jun 07, 2013 12:20 am

Now comes a soldering iron. Hakko or Wellers are fine, get one with some sort of temp control. For the hobbyist and even professional, it still pays to use lead based solder, it melts at a lower temperature and flows better. Sorry EPA, but for the 1/4 pound of solder that I'll use in my lifetime, it can be lead. I lose more lead sinkers or fire more rounds than that every few years.

My eyes are old and the business can buy a good stereo microscope, but if you can still see an illuminated magnifying lamp is fine for a lot of work. That includes surface mount. I picked up one a long time ago either at a company auction or someplace like http://www.weirdstuff.com
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Another thing to buy is some reading glasses. Head on down to Walmart and pick up the highest number they have. I wear them over my normal glasses when working on boards, I guess that makes me 6 eyes...

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Re: Minimum tools for DIY electronics

Post by basicchip » Wed Jun 12, 2013 3:25 pm

Oscilloscope-

If you really get into electronics you will eventually want a scope of some sort. You can pick up Tektronix 2000 series scopes for less than $200 on ebay, which is one that I would recommend and one that I have. I would not go with earlier models, and these were the best you could get when I started working and cost upwards of $5K. They are analog scopes, but are pretty fast and won't fool you with aliasing of a sampling scope (which if you ever do TV -- NTSC work can be an issue). I also have a digital scope for measuring long time interval or one-shot events. Though I picked up a 2 channel USB scope that is part of my mobile tool box, and is good enough for a lot of things. When I bought it about a year ago the Link Instruments MSO-28 seemed to be the best bang for the buck.

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Re: Minimum tools for DIY electronics

Post by basicchip » Sun Jan 25, 2015 1:09 pm

Soldering irons-

The typical pen soldering iron is too big for doing surface mount work. I have a couple different ones, an old Weller EC-3001 that is no longer made, and when it got hard to find tips, I bought a Hakko FX-888 (about $90). You need some good fine point tips for SMT work. Since then the internet has found me sources for the old Weller tips.
fx888.jpg
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Weller has a WLC-100 station that looks like it might be good at around $50. I'll see if I can check one out when I'm at Fry's again.

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Re: Minimum tools for DIY electronics

Post by basicchip » Sun Jan 25, 2015 1:36 pm

I started with some SMT kits to keep a stock of parts. Eventually that built up to a lot of things to sort through. You can get parts organizers for electronic parts, but as SMT parts are very small, that can take up a lot of space. A friend built one of these for himself and one for me. It started with a wood box mounted on a lazy Susan plate. Into that box are plastic sheets about 11.5 inches square. He found some covers for fluorescent lights that were made up of a grid of little boxes, and small glass vials that fit in them perfectly. The biggest problem was convincing the vial supplier that we weren't selling drugs, as we bought a few thousand.

So in this box, less than a cubic foot, I have all the 0603, 0805 and 1206 5% values for resistors and caps, and a shelf of a large variety of transistors and diodes.
partsbin.jpg
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Re: Minimum tools for DIY electronics

Post by basicchip » Sun Jan 25, 2015 1:47 pm

Soldering SMT parts can seem daunting at first, but if you start with the 1206 parts, you will find it is easier and faster than handling through hole parts. No bending leads, pushing them through the holes, flipping the board over, spreading them apart, soldering them with the board upside down, and then clipping the leads.

Basically put some solder on one side of the pads (this was done with +2.50 reading glasses and GOOD light)
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Next hold the part with tweezers, melt that solder on the one pad and place the part, remove the iron and hold with tweezers for a second.
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Next rotate the board 180 and solder the other pad
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Pretty easy after a few times with a GOOD fine tip iron, GOOD light, reading glasses, and fine gauge solder. That is 0.010" diameter lead solder in the pictures.

That happens to be an 0805 resistor and if you blow it up you can almost make out the 5.6 marking for 5.6 ohms, lots easier than remembering "Bad Boys..." color codes. For reading those a 10X loupe is real handy. eBay to the rescue again as those are a couple bucks, or I've picked up a few as freebies at electronic trade shows.

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