Hot Mad Science How-Tos

How To: Create a PCB Etchant That Automatically Improves After Each Use

Etching your own circuit boards is tons of fun, but etching requires strong chemicals to dissolve the copper plating on blank circuit boards. The normal ferric chloride solution works well, but can be expensive and leaves permanent stains. Luckily, we can whip up our own etchant at home with everyday chemicals! Better yet, our new etchant will turn an eerie green color rather than the dull brown of ferric chloride.

How To: Make Super Fizzy Carbonated Beverages at Home with Dry Ice

Want to make your own soda or maybe just bring a dull one back to life? Homemade sodas don't always live up to the store bought ones because they can taste flat by comparison. This quick and easy method makes super fizzy drinks with only four ingredients. Because putting dry ice in a sealed bottle would effectively turn it into a bomb, you'll need to make a safety valve for the bottle.

How To: Build Your Own Mini Altoids Guitar Amp for About $5

I love making beeps and bloops with the Arduino pitches library, but sometimes archaic 8-bit tunes just don't cut it. Whether you want your robot to terrify your enemies with a demonic synthetic voice, you just need a pocket boom box on the go, or you want to a miniature guitar amp, a simple LM386 amplifier can crank up those signals loud enough to play through any speaker.

Spice Rack Explosives: How to Make Gunpowder with Salt & Sugar

The best chemistry experiments are those you can perform with items already laying around your house. With only some sugar, salt substitute and an instant cold pack, you can make your very own gunpowder! Being able to make homemade gunpowder without a trip to the store can be a lifesaver, no matter if it's just for testing out a Civil War-era musket, blowing up stubborn tree stumps, or preparing for battle when imperialists overrun your country.

How To: Build a Long Range Laser Spy System for Eavesdropping on Your Neighbors

Eavesdropping from a distance can be tricky because it usually requires some sort of bug or transmitter. It's easy to transmit audio through lasers, but you can also use lasers to build a microphone that picks up audio from a distance. LucidScience built the Laser Spy System for about $20. To make your own, you'll need a cheap laser pointer, an NPN phototransistor, a headphone amp, and a few other small pieces listed below. A light-to-sound circuit is installed in a small plastic box with the...

DIY Blacksmithing: Forge Your Own Steel at Home!

Metal is a great material to work with. It's rigid, tough, malleable and conductive, but sometimes the part we need doesn't exist in any store. In order to create custom pieces, you need to either melt the metal and cast it in a mold, or heat it until it's soft enough to shape with your hammer. Properly melting metals can be a bit dangerous in our home shop, but we can make a coffee can forge for all of our home blacksmithing needs.

The Sweet Smell of Success: DIY Smoke Mix with Sugar and Potassium Nitrate

I finally got around to trying out another one of Will's mad science experiments and found out that this one was actually more satisfying (and less frustrating) than my slightly uncooperative jar jet. There's something very pleasing about making potassium nitrate at home in the kitchen and then watching the transformation from semitransparent liquid to spiky, frozen crystals. That was the best part for me, second only to igniting it with its sugar companion.

How To: Make a Simple Fog Machine to Prank Your Roommates

Like theme music, I always feel that I need more fog in my life. Fog can be useful for many reasons—warding off smaller siblings from your bedroom, keeping curious hands out of your cupboard, and tricking your friends into thinking there's something horribly wrong with their vehicle. So, today we'll be making a very simple fog machine for small scale applications.

How To: DIY Flanagan Neurophone Lets You 'Hear' Sounds Through Your Skin

In 1958, Patrick Flanagan invented the Neurophone, a device patented in 1962 that allows radio signals to be picked up by the human nervous system. The skin is the organ that receives the signal, converting it into a modulated molecular vibration, which the brain interprets into sound. Basically, it gives one the ability to 'hear' through the skin, making it sound like the audio you're hearing is actually in your head. It's kind of like having headphones in your brain. The only problem was th...

How To: Send Your Secret Spy Messages Wirelessly Through Light with This DIY Laser Audio Transmitter

Looking to transmit some super-secret audio communications to your other spy buddies? A laser is the perfect tool for getting your sounds heard from a small distance—without anyone intercepting them— even if it's just a cover of your favorite pop song. A laser audio transmitter uses light rather than radio waves to transmit sound. This is a much more secure way to send audio communications because the laser is a focused beam of light, whereas radio waves are not controlled, so they can be pic...

How To: Design Your Own Custom Arduino Board Microcontroller

Microcontrollers are great. You can do anything from water your garden to catch wildlife trash diggers in the act—and on the cheap. I prefer to use the Arduino microcontroller because of the large and helpful community built around the website. Though it is my favorite, there are some drawbacks to using an Arduino board in every project. It gets expensive, the board can take up too much space, and the rat's nest of breadboard wires are a pain to repair.

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