Attach a spool of wire and a hypodermic needle to a ball point pen barrel to make an aid to make point-to-point wiring easier to do. The board shown is a microprocessor system board with a 8085, 2764 and 6464 - that is, the CPU, EPROM and RAM - and some additional glue circuitry.

Step 1: The parts

A hypodermic needle. Get the disposable type with a plastic collar, as this will need to be cut down to make it fit in the nozzle of the ball point pen.

A (used) ball point pen. I acquired one with a metal nozzle as it would probably last longer.

The spool of enamelled wire was from a relay, 12 V changeover contacts - the rest of the relay was dismantled with care not to damage the spool of wire. Other sources are transformers and rf chokes.

Some two component epoxy to cement the needle to the nozzle.

A screw long enough to hold the spool of wire (not shown)
<p>I made one with a small variation. Instead of using a screw to hold the spool of wire I used a 2mm thick copper wire which I soldered in such a way to form the shape you see in the photos.<br><br>It works pretty well and it made prototyping on perfboard much easier for me. Thanks for sharing.</p>
<p>Point-to-point wiring at the prototype stage or one-off project is far easier than techniques like stripboard. I have been doing an 8-digit 7-segment LED counter with a 24 pin Maxim driver and 28 pin Atmel (Arduino) chips. I soon gave up stripboard (too much scope for errors) and dug out my old wire-wrapping gear.</p><p>I'm glad I kept it as the component parts are available now, but inflation has taken it's toll - original wrapping/unwrapping tool &pound;80 for example. The wire is also available as Kynar covered 0.5-mm diameter. It's biggest advantage over enamelled wire is its clean stripping and silver-plated copper core. It's much finer than stuff like CAT5e and the Kynar sheath is very tough. The stripping tool is simply a piece of thin steel with a &quot;V&quot; notch.</p><p>I also stocked up years ago with needles and syringes. Like many other things that used to be easily available, including most chemicals, the bad boys have queered the pitch for legitimate users - nitrous oxide will be next. ID to buy contact adhesive?? Loctite used to do blunt needles for some of their superglues and you can get stainless steel tube right down to 1/16 inch OD.</p>
very cool thanks!
aren't hypodermic needles illegal?
If they are illegal where you live, you could probably get away with using an inflation needle, like you would use to pump up a soccer/volleyball/basketball with.
Not in Canada at least. We can go to any hardware, drugstore, or even the dentist for just one or two. I can also find them at pet stores sometimes, and the flooring department at most warehouse stores. You use the large 50CC ones for flooring, to apply glue to area's that are bubbled. Either way, they will have those metal tips you're looking for.
That depends where (and who) you are. some places put legal controls on the possession and transfer of hypodermic needles. this has changed with the spread of HIV Blunt hollow needles are legal most places, they are used in things like inkjet refill kits. It may be possible to roll a needle for this instructible from stainless steel shim (eg the sliding cover of a 1.44MB diskette) as the needle is just used as a guide for the wire.
why would they be? unless they are filled with a substance that is...
the last time i checked you can't buy hypodermic needles off the shelf anywhere legal. and besides how would you get a hold on one legally
eerrmmm just go to the chemist(UK)and ask for a box of them.
I got a free one from a pharmacy to <a rel="nofollow" href="http://www.curiousinventor.com/blog/27">apply acetone to an acrylic box joint</a>, and I think the pharmacist actually believed me when I said it was for a science project. Beforehand I got turned down by a walk-in care place--they did not believe me.<br/><br/>You can also buy non-super-sharp ones in bulk from mcmaster or places that sell solder-paste dispensing syringes. <br/><br/>
I'm sure all the Type I Diabetics are plenty of proof that they're NOT illegal. Just because something is not convenient or easy to find doesn't mean it's illegal.
you can find needles at farming supply stores, pet supply stores, pharmacies, vets, etc. They are not illegal in most places in the U.S., though if you are caught with some drugs and a needle it will probably be called paraphernalia
you can also get them out of a printer cartridge refill kit
I would guess that any reasonably-stocked pharmacy should have these (behind the counter), not every diabetic has an insulin-pump, so manual injection is vitally important. Professional piercers also use a variety of sizes of hypodermic needle, anywhere from 20ga all the way up to 2ga (or at least I've never seen anything larger than a 2)
that's because there isn't exactly an enourmous market for over-the-shelf hypodermics, but i haven't been to a pharmacy - i am sure if you looked around you could find somewhere to buy them in person. just do a little bit of google searching, you can easily find perfectly legal medical supplies without any need for you to fax them your phd or something stupid.
If you can't get a hollow needle, try it with a propelling pencil with a metal tip. Or you might try using the tip of a ball point pen after emptying the ink out, and use a needle to pop the ball.
if anyone could come up with a way to combine this ible with<br>http://www.instructables.com/id/Precision-Wire-Stripper---new-video-links/<br>i would be very grateful...<br>
I appreaciate you making this instructable but I cannot overlook the fact that readers might have the impression that EWP (enamel wiring pen) is only useful for creating rat's nest like wiring which is not the case.<br><br>I've attached the fabulous work of Markus Gritsch who is a world class talent on applying EWP. You can see <a href="http://elm-chan.org/docs/wire/wiring_e.html">the related page</a> on his site.<br><br>Also take a look at <a href="http://www.rrunner.co.uk/">Roadrunner Electronic Products Ltd.</a> who seem to be the #1 EWP tool maker<br><br>Lastly, <a href="http://info.ee.surrey.ac.uk/Workshop/advice/grotwire/index.html">there's a good tutorial</a> on EWP.
Nice instructable, but what is the advantage of point to point wiring?
The advantage is that you can use any old perforated board to wire your circuit. All other forms of wiring up circuits need to make use of some sort of a prepared or customised circuit board.
Cool. What do you do if the wires overlap? Could they cause a short circuit?
No, because the wire is insulated. I am using enamelled wire from an old relay coil for the one in the picture. Since the enamel in this case is somewhat coloured like copper, it might seem that it is bare copper. Enamelled wire is available in various colours, you might like a search on the net for details.
What size soldering iron do you use, and do you strip the wire ahead of time, or just solder and hope for the best?
I'm definetly making this now.
Okay, thanks!
Very useful. Thank you!
cant u just use a solder injector to a soldering iron lol u just need to pres a buttonin ur hand or a foot switch?????
This actually was a product back in the late '70's: the Vector Wiring Pencil (see below).<br/><br/>The solderable magnet wire is still available; I bought a 1/2 lb (230g) spool of <em>Belden 8058</em> &quot;<em>Beldsol</em>&quot; 36 AWG (0.01 mm<sup>2</sup>) wire on eBay for $40.<br/><br/>The Mouser catalog says about this wire:<br/><br/><em>Dual insulated magnet wire that combines the excellent dielectric characteristics of Polyurethane and the known toughness and solvent resistance of a Nylon overcoat. Rated by IEEE tests for 270&deg;F usage and will solder without insulation removal at 750&deg;F.</em><br/><br/>Mouser Electronics has this wire: <a rel="nofollow" href="http://www.mouser.com/Search/Refine.aspx?Keyword=beldsol">http://www.mouser.com/Search/Refine.aspx?Keyword=beldsol</a> though it costs about $53 for the 34 AWG (8057) and $61 for the 36 AWG (8058) in 1/2 pound quantities.<br/><br/>The wire has on its label the following note:<br/><br/><em>This magnet wire may be different from what you have previously purchased. This insulation has been improved so that it will stand more heat (130&deg;C) and it can be stripped by use of a soldering iron or gun at (750&deg;F).</em><br/>
I've <a rel="nofollow" href="http://gallery.me.com/bikenomad#100015">uploaded some images</a> of my 1970's Vector Wiring Pencil.<br/>There are three other detailed images there.<br/>Note in this image the spool of Belden Beldsol wire that I got recently.<br/>As I recall, it was helpful to use your finger on the side of the pen where the wire was exposed to modulate the tension. When you wrapped the wire around a component lead you wanted tension; when you were just going to another point you didn't.<br/>
how about an inflation needle for air pumps? Tube is a bit wider than syringe needle; how important is width?
Is scraping always necessary with enameled wire? Is there a temperature of soldering iron that would solder wire without scraping?
some enameled wire can be easily stripped by the heat of soldering some cant, scraping helps heat transfer ans wetting of the copper once wet the solder flows under the enamel and floats it off. the pen can also be used with proper wirewrap wire (eg Kynar)
wow.... just wow.....
Nice idea! I'm building one of these for myself right now, and I intend to build one for the lab at work tomorrow.<br/><br/>Anyway, for those of you wanting to make one of these dispensers, note that surface mount pcb assembly technology uses the type of needle tips pictured in the instructable for dispensing electronic solder paste and glues (except that the tips are already ground down for you).<br/><br/>These come in a variety of gauges from 14 to 30. They are available in single unit quantity (at <a rel="nofollow" href="http://store.sra-solder.com/section.php?xSec=9">http://store.sra-solder.com/section.php?xSec=9</a> and probably others) and are so cheap ($0.15 each) that you should be able to buy a full set of gauges for a couple of bucks.<br/><br/>On the other hand, the company I mentioned has a minimum order amount of $25; of course, they carry an excellent line of cheap soldering tools (no, I don't work for them, but I am an excited new customer), so it may be harder to stick to $25 maximum than $25 minimum. ;-) <br/><br/>Also, the type of wire he mentions is traditionally called &quot;magnet-core&quot; wire. Some of the best rework I've seen has been done using this stuff. To answer one of the concerns mentioned in other comments, it typically doesn't have the same problems peeling away from the wire that the Kynar wire-wrap coating does.<br/><br/>Cheers!<br/><br/>
at first glance i couldn't understand what you were doing with this until i re-read the comments and found out that the wire your using is insulated,now i see just how'brilliant'this actually is. EXCELLENT!!!!!!!!!!!!!!
a very nice and genius way but the wiring of complex electronic circuits in this way may be unpractical though and may lead to the problem that is called in electronics the rat's nest! nevertheless its a genius idea for simple stuff! well done!
Thats amazing! I will have to make one for my next electronics project!
COOL!! i could have used this for making my things. This is an AMAZING idea though THANKS!!
I'm going to just add that you want the gauge of the needle to be at least 20 - probably more like 18, so those insulin needles are out. Awesome idea!
You could also use this for soldering :). Great idea , keep it up
Very innovative!
holy wowness
Very ingenious!
Lovely gadget!<br/><br/>Back in the Olden Days of electronics, people would make prototype circuits (or even entire systems, such as the Apollo Guidance Computer) using something called <a rel="nofollow" href="http://en.wikipedia.org/wiki/Wire_wrap">Wire Wrap</a> technology. Rather than soldering, you would have a special pen-like tool that would tightly wrap a fine wire around the post of a component. Surprisingly effective, and so much faster than soldering everything.<br/><br/>I actually did my first EE thesis project back in mumble88mumble using this stuff, building a frame grabber for an IBM PC/XT (gah - remember those?), running at a sampling speed of 10 MHz. <br/><br/>Nice technology, and this pen reminds me a lot of that. I assume you can still find the fine wire wrap wires, if you prefer to use plastic-insulated rather than enameled wire...<br/>
<em>Wire wrapping</em> is alive and well! They still make motorized wrapping tools for the big jobs (I've got a little hand-spun one).. I still prefer it for one-off stuff...<br/><br/>Anyway, this 'Wiring Pen' is a pretty clever idea...<br/>
this is just amazing! something is wrong with you, because you are too smart
AH THIS IS SO NEAT! i could have really used this on some of my projects.
INGENIOUS!!! A simple solution to a complicated problem... Never like P-P Soldering myself...

About This Instructable


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Bio: Employed as an Engineer in Electronics. Interested in building small circuits around tiny chips (the electronic kind).
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