Introduction: MacGyver a Welding Helmet to View the Solar Eclipse
So, I couldn't find any eclipse glasses, but I couldn't let that stop me. The essence of MacGyvering is overcoming obstacles with whatever you have at hand. I hacked together a TV remote control, a bottle cap, and an auto-darkening welding helmet to make a capable and safe eclipse viewer.
The basic principle of this thing is to used the pulsed infrared light from a cheap remote control to "trick" a normally automatic welding helmet into being a useful viewer for solar eclipses or other super bright stuff.
In this Instructable, I spent some time packing information into the images. Be sure to see the annotations on the images for extra details, ideas, and facts useful to any aspiring MacGyver types.
I have mixed feelings about the way that so much tutorial content has become video-based, but in this case, I felt it was useful and afforded some good opportunities to teach. For example, in the video I use a custom infrared viewer to show exactly what the remote is doing in the infrared. Enjoy.
Step 1: Materials List
Gather up these materials:
- Autodarkening welding helmet (this is a Harbor Freight 46092)
- Alcohol or cleaner (this is cheap vodka - a great cleaner and disinfectant)
- Aluminum foil tape or light blocking tape (2", Nashua)
- 2"/50mm plastic cap from bottle (I don't know what this one came from, actually)
- Small remote control (mine was from a toy media thingy)
- Paper towels (like these - roll type or a cloth will work, too)
- Hot glue gun (Adtech Pro 100)
- Not pictured - black hot glue sticks. I strongly prefer Surebonder 707.
- Of course, normal hot glue will work, too - or doublestick tape, or the foil tape.
Step 2: Clean Your Helmet
Pour some alcohol on the paper towel and clean your helmet. You should do this even if it's a new helmet - it may have oily residue from manufacturing. Mine was filthy from years of welding and grinding.
You only need to clean the area where you are going to stick the remote control. If you were in a tight spot and didn't have alcohol or a paper towel, you could use the condensation from your breath, and the cleanest part of your shirt or pants to clean as well as you could.
Step 3: Glue the Remote in Place.
As demonstrated in the video, the pulsed infrared light from the remote causes the helmet's window to darken. Glue the remote on the side with hot glue, close to the IR sensors on the front of the helmet. This will make it easy to bounce the infrared light over to the sensors. The cap basically serves as a little "light dome" that contains and bounces the infrared signal over to the infrared sensor.
Tip: If you have a surface that doesn't want to be glued with hot glue (like aluminum, for instance), you can make things work much better by preheating the surface. By putting the aluminum in an oven, heating it with a torch, or even leaving it out in the sun, you can make it possible to glue with hot melt adhesives.
If you didn't have a cap, there are still many ways to direct light from the remote. You could use a bit of mirror from a makeup compact. You could use a piece of broken glass as a light-pipe. You could also use the bottom of a soda can, cut with a swiss army knife. ;) There is nothing essential about the bottle cap.
If you don't have a remote at all, you can still test or trigger the auto darkening lens for a brief time. Use a lighter, or matches, or anything that can make a spark. You can even use the face proximity sensor on your smartphone (which is usually near the selfie camera). Anything that makes a pulsed or random IR signal will work.
Step 4: Glue the Cap in Place
As previously mentioned, the cap's job is to reflect the infrared light from the remote into one of the sensors.
Glue the cap so that the LED on the front of the remote and one of the sensors are inside of it.
These kinds of caps are typically made of polyethylene, which transmits some light in the near infrared (750-1400nm). This cap is white, meaning it is probably tinted with titanium dioxide, which is reflective in the near infrared. You can find polyethylene everywhere - hula hoops, cutting boards, bottle caps, car parts, pillow filler... it's an incredible material that has a lot of nice properties. You can bend and form it with a heat gun. It's lubricious, easy to cut and shape, and cheap. It can even be blended with synthetic waxes to make machinable wax. Heat up a soda bottle cap with a lighter or heat gun and jam it under that uneven table leg. It will fill the gap and prevent the table from rocking.
Definitely useful for the aspiring MacGyver.
Step 5: Tape It Up
Tape over the cap to prevent infrared from passing through it. Then cut a smaller piece of tape and cover up the other IR sensor. You want the tape to be a bit larger than the sensor, as shown in the images. This will prevent light from leaking around the edges and spoiling your fun.
Sensor locations are indicated in the fourth image. They are the two small black dots on the front face of the welding helmet.
The sensors themselves appear black to our eyes, but transparent in the infrared. This is possible due to the fact that most dyes (as opposed to pigments) absorb in the visible, but not in the near infrared. You can hide infrared cameras and LEDs behind black plastic. Just look at the black domes in a supermarket, or the top of your home TV remote control. That plastic is transparent to the camera or LED, but black and opaque to your eyes. One way to improvise an IR low pass filter is to cross the lenses from polarized sunglasses. With one lens at 90 degrees to the other, all visible light will be blocked, and only IR will pass. You can actually see into the near IR just a little. Take your crossed lenses out at night and look at the LEDs on a security camera... you will see a faint red glow, but not much else.
Step 6: Customize Your Helmet
I drew a silly face on my helmet to make it more fun. This is not really MacGyvering, but it is required by internet law because I did not include any pictures of cats.
The turntable in this image is made from a bearing block and wheel that I extracted from a surplus yard.
Step 7: Test Your Helmet
The moment has arrived! Take your helmet outside for testing. At first, do not look at the sun, just look at the landscape around you. Press a button on the remote to see if the lens darkens. If it works, point the helmet at the sun and try again. At this point, you should have achieved manual control of your formerly fully automatic helmet!
If you have done a good job of covering up the sensors, the helmet will continue working even when pointed at the sun. If something fails here, check that you haven't covered up too much of the main solar cell. Also check that there are not more sensors across the face of the helmet. High quality helmets will have 2-6 IR sensors across their face.
Almost every helmet like this has adjustable tint. Do not forget to set your helmet to Shade 13 or Shade 14 - anything less is not safe for solar observation.
Have fun! Hack the planet!
Step 8: Cleaning Up.
As mentioned in the video, you may wish to return your helmet to normal operation. This black hot glue is super tenacious stuff, but it can be easily removed with isopropyl alcohol. Just wet the glue joint with alcohol, wait a moment, and the glue will release in an almost-magical way. I like to use a brush to apply alcohol, but toothpicks, sticks, droppers, or straws will work as well.
In a pinch, you can also use ethyl alcohol like vodka, but it will take longer to work. Ethyl is a great alcohol to keep around. It tastes good, it can clean wounds, glass, and electronics, and it can serve as a basic fuel. it can even neutralize a jellyfish sting. Surgical-grade cyanoacrylate (super glue) is made with ethyl instead of methyl alcohol, because methyl is a poison. Vodka is also great to have in an emergency, you can comfort a friend or bribe a guard. ;)
Thanks for checking out this Instructable and going through the text and annotations. I hope you learned something useful. As I'm finishing typing this out, I realized how funny it is that the Grand Prize winner gets... a "Mac".