Instructables
If you work with your hands and want to have more light where you're working, these hand lights (okay.. forearm lights) work great and are pretty simple to make. Use them for working with crafts, electronics, changing light bulbs, visiting the fuse box, rummaging through the crawl space, or cleaning out that one unlit closet.

I like to work on stuff in my living room, because that's where all the comfortable furniture and the good music system is. Unfortunately there's not a ton of light. I tried a task light but it got uncomfortably warm and cast harsh shadows. I tried the head mounted lamps like the cool DJ's wear, but I didn't like where I had to hold my head to see my work.

So I made these. They'll give you light right where you hands are, wherever you move them. Wearing one on both arms makes sure there's always enough light on everything, and they're pretty light and comfy. I've worn them for hours without noticing. And the little arms are adjustable so you can tweak where the light goes. Just be careful scratching your nose, they're bright enough they'll hurt if you look into them at close range.

I've been using them for carving and working on electronics. But I think it would be cool to make a couple with UV LEDs and break out the blacklight paint for DJing.

These instructions are for making one, but you'll probably want two.

Time: Less than an hour

Skills needed: Basic soldering, hot gluing, wire stripping etc.

Total cost: About $8-12, including the batteries.

Thanks!
I managed to be one of the winners in the Get the LED Outcontest! Thanks everyone for their support!

Parts:

  • 1 Battery holder for 3 AAA batteries.
  • 3 AAA batteries.
  • 1 mini toggle switch. (SPST. Skip this if your battery holder has a switch, or you just want to turn it off by taking the batteries out.)
  • 18 inches of 2 conductor stranded wire. 20 gauge or so.
  • 18 inches of Velcro. Hook or loop.
  • 1 inch of Velcro (the mate of the Velcro above)
  • 3 White LEDs: (I used 3, 7000mcd 3.5v, 25mA LEDs, though fewer, brighter LEDs would work too.)
  • 3 resistors, 47 ohm. (Or whatever your LEDs need. Check here.)
  • 18 inches of 9 or 11 1/2 gauge aluminum wire. AKA armature wire.
  • Solder
  • Hot glue
  • Electrical tape/heat shrink tubing.

Tools:

  • Soldering iron.
  • Hot glue gun.
  • Wire cutter/strippers.
  • Pliers.
  • Scissors.
 
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Step 1: Collect all your parts and tools.

Picture of Collect all your parts and tools.
To review:

Parts:

  • 1 Battery holder for 3 AAA batteries.
  • 3 AAA batteries.
  • 1 mini toggle switch. (SPST. Skip this if your battery holder has a switch, or you just want to turn it off by taking the batteries out.)
  • 18 inches of 2 conductor stranded wire. 20 gauge or so.
  • 18 inches of Velcro. Hook or loop.
  • 1 inch of Velcro (the mate of the Velcro above)
  • 3 White LEDs: (I used 3, 7000mcd 3.5v, 25mA LEDs, though fewer, brighter LEDs would work too.)
  • 3 resistors, 47 ohm. (Or whatever your LEDs need. Check here.)
  • 18 inches of 9 or 11 1/2 gauge aluminum wire. AKA armature wire.
  • Solder
  • Hot glue
  • Electrical tape/heat shrink tubing.

Tools:

  • Soldering iron.
  • Hot glue gun.
  • Wire cutter/strippers.
  • Pliers.
  • Scissors.

Step 2: Create the support arm

wrist_lights_wire_bend_one.jpg
wrist_lights_battery_tape.jpg
First I put little pieces of electrical tape over the visible metal bits of the battery holder to prevent shorts from our armature wire. Don't use too much tape because it'll conflict with the hot glue we use later. (You want to apply hot glue to the plastic, not to the tape.) Skip this step if you're using a less cheap battery case.

Take the armature wire and bend it around 3 1/3 sides of the battery case. It should generally be snug, but leave a small (1/8") gap along the "inside back". That's the side that will be closest to your chest and closest to your shoulder. (This is where an image is worth a thousand words.) That gap is where you'll secure the adjustable strap, so make sure your Velcro strap will fit through it. Note that this one is a right handed light. For a left handed one wrap the wire the other way.

When you're happy with it, hot glue it in place. Make sure you don't put any glue on the part where the strap will go. And don't get any glue inside or you'll have a hard time getting batteries in.

Step 3: Wire up your LEDS.

Solder the resistors to your LEDs.

Since 4.5 volts is too much for most LEDs you need to put a resistor in there to keep them from burning out.

In most cases a 47 ohm resister on each will work. Use the LED resistor calculator here to be sure. (The values for my LEDS: 4.5 volts, 3.5 forward volts, 25mA forward current, and 3 LEDs.)

It doesn't matter if you put them on the long or short end of the LED, just put them all on the same end so you don't get mixed up and have to spend 20 minutes desoldering them. (Like I did.)

Now would be a good time to check them with your battery pack to make sure you've got it right, The long end of the LED goes to the +, short to -.

If they all check out then solder the three LEDs together. (Or if you got one big, bight LED you skip this step.) Solder all the free ends of the LEDs together along with one side of your two conductor wire. Similarly connect the free ends of the resistors together with the other strand of your wire.

Apply some electrical tape or shrink tubing to prevent short circuits.

Now would be a good time to test it again and make sure they all light up and you don't have any short circuits.

Step 4: Create the Velcro strap

wrist_lights_strap_close.jpg
wrist_lights_strap_tab.jpg
wrist_lights_strap_complete.jpg
Make sure you have enough Velcro to fit around your forearm with a several inches to spare. For me 15 inches was enough, but I don't spend lots of time at the gym.

Hook or loop doesn't matter, as long as you have a long piece of one and a short piece (an inch or so) of the other.

Hot glue one end of the long strip to the bottom of the battery enclosure. Make sure it's hook or loop side facing the battery holder. Put it on the "up the arm" end, furthest away from where the armature wire sticks out, and pointing away from our little gap we left for our strap. Again, the picture is worth a thousand words.

When the glue cools, put the strap through the strap hole we left in step one. Then hot glue the short bit near the end of the strap. Leave about 1/2 inch to make it easier to pull off. Glue it on the hook or loop side, not the smooth side. (You could also stitch it, but the glue gun is already hot...)

You should now have an adjustable strap that will secure it to your arm.

Give it a try, put your arm through the strap and see how it fits.

Step 5: Finish connecting the LEDs

While you're trying the strap out, bend the remaining bit of the armature wire to a goodBrontosaurus neck shape, and cut it to length. For my arms I found that I liked the lights about 6 inches from the back of my hand, which meant trimming the wire to about 6 inches from the front of the battery case.

When you find a length you like, hot glue the lights in place and wrap the trailing wire around the armature a few times to keep it out of the way.

Step 6: Connect the switch

Picture of Connect the switch
Note for the lazy : You can get a battery enclosure with a built in switch, or simply skip the switch and just take the batteries out to turn it off. But why wouldn't you want to add a toggle switch? Toggle switches are awesome.

Connect your switch between one of the leads from the battery holder and your LEDs. Connect the other battery lead directly to the LED wire.

Again check to make sure that everything is wired the right way before soldering into place.

Try to keep the leads as short as possible so you don't have to worry about them catching on stuff. If you have extra wire you can wind it around the armature wire before soldering.

Hot glue the switch into place. I also covered the wire with glue to prevent shorts, keep it from catching on stuff, and because hot glue is one of the most fun ways to get first degree burns.

Step 7: Use!

Put it on your arm and fire it up! Tweak the position of the armature wire and make the individual LEDs to make sure they direct light where you want. I wear them just below the elbow, half way between the inside and side of the arm.

And lastly: Make another one, they work better in pairs. And your second one will go much faster.

Step 8: Become A Master Of Hand Lights

Picture of Become A Master Of Hand Lights
Did you make this?  Post a photo of what you made and you'll earn a Master of Hand Lights patch* and your name on the Hall of Fame.

*If I have extra patches to hand out.  Which I do.


Masters of Hand Lights

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ScubaSteve3 years ago
Reminds me of the goonies.
phenoptix3 years ago
Wow product of the day! Been a while since I've seen this project! There were some awesome entries for the particular "LED out" contest, good prizes too (especially the runner up prizes ;)) Was looking at the Monkeylectric website only yesterday, the video pro 7 is amazing.
GIJane19683 years ago
My 7 yr old son and I put together a pair of these. He loves them. Now he wants to make them for Christmas presents.

I am wondering if you could do this project with only 1 LED instead of 3? If so, what size LED and resister would you suggest? Would the power input be the same too?

Please keep in mind I am not an electronics geek type. But I am willing to learn.

Thanks!
Sergei-3 years ago
mmmmmm so you have to constantly keep you arms in that position or move around the lights every couple of seconds

wouldn't it be more effective on your shirt or shoulder or any where like a head unit so you can freely move your arms around

even a torch in your mouth allows for better light
Grathio (author)  Sergei-3 years ago
Quite the opposite. When you have a head or body mounted lights you have to hold your head or body in position to keep the light pointed at your work. When they're mounted on your hands the light is automatically pointed at where you are working.
Sergei- Grathio3 years ago
Hi

Thats my point you have to reajust for different angles but with something like head mounted you just look at it any way and don't need to adjust if not in the same possition

And somthing like shirt mounted will give you a better spread of light to cover the work area if it needs to be brighter just hold it closer and if it's to bright just a little further, and for both it just needs one set of lights not 2

Your idea is another way of looking at it anyway
and makes people think of other ways
keep up the experimenting
menacel5 years ago
is it ok if your battery compartment holds 4 AAA batteries? or can it only be 3?
Grathio (author)  menacel5 years ago
It's fine, though you'll need different resistors since you'll be putting more voltage through the circuit.

There is a simple calculator at this link to figure out what resistors you need. If you're going to use 3 of the same type LEDs I used you'll need one 100 ohm resistor for each LED.
menacel Grathio5 years ago
cool thanks
put your leds in series instead of in parallel.
2 leds in series creating a row, and 2 rows parallel with each other
kadris3 menacel4 years ago
when only 4 cell holders are available, make a "dummy" battery. i have heard of using a dowel which is drilled down the middle. place copper disks on each end and solder a wire running through it. bits of old circuit board work well, as does cu flashing. that way u still need use only 3 batts and don't need larger resistors to throw away more power. 4.5 vdc(source) minus 3.4vdc(the led) divided by .02(20ma)=55 calculated ohms. for long term use go to the next highest fixed resistor.
'able a good idea. keep up the excellent work. unclecytheledguy.
gtsky3034 years ago
Great idea, similar to the HexLight shown on the tv show Pitchmen:

http://dsc.discovery.com/tv/pitchmen/inventions/inventions.html
Grathio (author)  gtsky3034 years ago
Shame that I published my Instructable more than a year before the HexLights episode.

Wonder if one of us was copying the other?
I do remember them mentioning in that episode that there was at least one patent on a similar type of device and that they wouldn't be able to make the HexLights. But then they made a slight change to the design and the patent infringement no longer applied.
I was just about to say that, but then i saw your comment.
miska_man5 years ago
Where exactly can you get this armature wire? I'm finding it hard to buy in small amounts. Can I substitute some other type of wire instead? Thanks, Miksa
Art supply stores. But you can also use heavy gauge copper wire -- like 10 gauge or lower -- any home center will have some. leave it insulated or strip it. Copper is pretty!
Grathio (author)  miska_man5 years ago
I don't know of anywhere you can buy it by the foot, unfortunately. Art stores have it in their sculpture sections, it can sometimes be called "Craft wire". One Supplier. Another. A great many suppliers.

You can also find something similar at hardware stores if you shop for aluminum wire, which can also come in a bunch of colors.

It has all sorts of uses.

You could cut up a wire hangar to use but it wouldn't be as good as aluminum. It would make it harder to build because the steel wire is harder to shape, and the the light position wouldn't be as easy to adjust because the steel is springy and won't say where you put it. But it would work.

excuse me can i ask what are the possible materials to replace the velcro
Grathio (author)  cjanhero5 years ago
Here are some other options, but Velcro will work the best:

  • Nylon strapping with a buckle (like these) You might be able to scrounge one from an old backpack or bag.
  • Make a metal bracelet from a wire hangar. Cut the hook out of a the hangar and bed the wings into a loop a little smaller than your arm. Glue in place. Make sure you cap any raw pointy bits of wire.
  • Shoe laces or ribbon. Take two shoe laces or lengths of ribbon and glue one to the front and one to the back of the battery holder. Glue the laces at the mid-point. Put it on your arm and tie 'em up. This will probably be a pain since you have to do it one handed.
  • Cuff from a sock. Cut the top 4 inches off an old sock and hot glue it on. It won't be adjustable, so make sure it fits right on your arm before gluing.
Those are my ideas off the top of my head. Anyone else have any suggestions?
Ok good, we have a Ben Franklin in town, so I don't have to wait on shipping from over the internet. How about the battery holder? Can I do a 4 AAA holder, or will that be too much voltage?
Grathio (author)  miska_man5 years ago
You can use 4 batteries, but it will likely change what resistors you use.

To figure it out either go here and put 6 volts for the source voltage and fill in the rest with the specifications from your LEDs, or you can follow this instructable to calculate the resistors you need.
I love your project mate. And i'm working on a way to miniaturize the design, in order to be able to fit 2 of these to my Wayfarer glasses for night study, Project making, late trips to the fridge etc, perhaps using a smaller LED, and smaller batteries, what do you think?
Grathio (author)  phant0m_sp00f3ra4 years ago
You certainly can shrink it. You could power them with a couple of watch batteries. (Or if you don't need a ton of light, basically just make a throwie.) Of course you'll need to change the batteries more often, but they should last a few hours at least.

For the late night lights, consider making them with red LEDs, they won't kill eyes that are adjusted to the dark
Adri3l4 years ago
I think your idea is absolutely astonishing, but instead of using "plenty" of electrical tape, why not use heatshrinking tube; just a 3am thought :)
Grathio (author)  Adri3l4 years ago
Of course!  I wanted to keep these instructions as simple as possible using the most common supplies, which means there are limitless possibilities for improvement.
knektek4 years ago
instead of 47 ohms, i used ohms law to figure out that r should be 120 for 
30 mA and 3.6v. nice idea! im going to make this with only 1 battery pack and a wire running down your arm and your other arm so you can have 2 sets for half the batteries! i had a thought that was wierd! run some wire from your power source through your underwear and next to your socks. that would feel wierd!
nolte9194 years ago
Ask, and ye shall receive.
I did things a bit differently.  I used just one resistor for all thee LEDs instead of one per LED.  The LEDs I used, Digikey C503C-WAN-CBADA151-ND ($0.54), are a bit more focused than yours.  If I was to do it again, I might us more diffused ones.  I also put a nifty little pot, Digikey 3352W-101LF-ND ($1.24), in parallel with the resistor.  It was a 100 ohm resistor and a 100 ohm pot so the resistance can be varied between 0 and 50 ohms.  I thought this would let me conserve batteries if I so choose and crank up the current when the batteries start to die.  I also used a push button, Digikey 518PB-ND ($1.19), to turn it on and off.  For the main supporting wire I used the wire from marking flags.  The flags used to mark buried cables, Harbor Freight item number 95264 ($1.49 for 25).  Instead of running two wires up to the LEDs, I used the supporting wire as one connection.  So I soldered the three LED cathodes right to the supporting wire.  The wire, being galvanized, wasn't exactly conducive to soldering but with enough heat and solder it seems to be holding quite well.  I drilled a hole through the battery holder and ran the support wire through it where the support wire first meets the battery holder to add a bit of strain relief.  This way adjusting the support wire won't put quite so much strain on hot glue alone.  The battery holder part number was Digikey BC3AAW-ND ($1.22).  For the velcro straps I used Harbor Freight item number 66125 ($1.99).  These already had a plastic buckle on one end so I didn't need to used your spiffy trick of using the support wire to make one.  Because I wanted to keep both ends of the straps but they were way too long I took a section out of the middle.  I just cut some out of the middle and sewed it back together.  I used a razor blade to shave off some fuzz to make the seam smooth.  I also shaved off all the fuzz where I hot glued the battery holder to the strap.

I love my hand lights.

If you'd like to add any of this comment to the main part of your instructable please feel free and thanks for the great idea.


SANY1878.JPG
Grathio (author)  nolte9194 years ago
They look fantastic!  Thanks for sharing your excellent build notes and materials list.  Your Master of Hand Lights patch is on the way!
mo55 years ago
great concept. :)
Leejin5 years ago
Wow, I can really see this being useful for gaming at night. Typing on my Laptop has always been terrible. I've been looking for a way to light my keyboard effectively. Grats on the contest!!
well at night you might want to use red LEDs so they don't mess up your vision. if you want to know what I mean go some place pitch black, wait till you can see without a light then turn on a flash light or something then turn it off. you wont be able to see for a while but with red light it wont mess up this vision.
Grathio (author) 5 years ago
Thanks for all the support everyone, you guys really made my week! I have just one request: If you make one, please some photos! The comments have some really great ideas and I'd really like to see what you guys can do. Post 'em in comments or email/private message me directly, whatever. A little shameless self promotion never hurt anyone!
dombeef5 years ago
Comgrats!
PyroMonger5 years ago
you should actually consider marketting this product...unless there already is such a thing around...I personally have never seen anything like it
The item is great, but more than that is the concept behind. A very, very useful tool with tons of potential. Please, listen to the other members and try to market it, or at least patent it before a big-box-blood-sucker company does, stealing YOUR great idea. Instructables like this make me addict to it. I've faved it. Cheers!
Grathio (author)  arirang7775 years ago
Thanks for the encouragement everyone! Now to find that five start Instructable on "Marketing" and "Bringing a Product to Market". Both things that I don't particularly have the temperament for.
Right? I want to see that instructable too. I can't tell you how many times I've wanted to try something out like that, but not had the first clue how to do so.
smh scoochmaroo5 years ago
I'd buy two =)
i second that. i would definately buy one of those.
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