Author: James Hobson

1404 Articles

Five-Stage Coilgun Powered By An Arc Welder!

September 2, 2016 by 20 Comments

Coilguns used to be the weapons of science fiction. Nowadays, whenever we see someone build one in their workspace it always serves as an inspiring reminder that the future is now. YouTuber [Cody’sLab] has done just that, assembling a rudimentary — but beefy — coilgun in his workshop.

The one in the video is based off an old design that used a 12V battery and without any fancy electronics. This new model has five coil stages along its two-foot length. Four wooden dowels and two copper tubes are arranged in a hexagonal shape to form the barrel and accelerator rails. The coils are each 100 feet of 14-gauge thin coated copper wire, all connected to a common ground. Still lacking any complex electronics, this version eventually gets its projectile launched a good few dozen feet. The ‘bullet’ is a piece of  steel with some brass to prevent it spinning in the barrel, while a hole has been drilled in it to accommodate a spring which keeps the two graphite brushes contacting the copper tubes.

The first test proved to be a little underwhelming, and [Cody] had to try something drastic — so he hooked it up to an arc welder to fire the projectile using 22V and 200A.

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Cat-Operated Cat Food Dispenser

September 1, 2016 by 56 Comments

Tired of being harassed by your cat? [MomWillBeProud] made a cheap, effective — and more importantly cat-operated — cat food dispenser.

The feeder is of an efficient construction — a double cat food dish, one container to store the electronics, and a Pringles can to act as the hopper. A simple servo rotates the hopper thirty degrees and back on each button press; using gravity to drop food through an opening that appears due to this motion. The button itself is an old IKEA timer and a piece of plastic large enough for a hungry cat to swat.

An Arduino controls the servo, and while [MomWillBeProud] skips over going into detail on his code, you can check it out here.

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DIY Electric Pennyboard Can Hit 40Km/h!!

August 29, 2016 by 21 Comments

Home-made transportation is a thriving area for makers to flex their skills. Looking to shorten their university commute, [doublecloverleaf] modded his penny board by adding a motor that can have him zipping along at 40 Km/h!

The electric motor is mounted to the rear truck and delivers power to the wheel gear using a HTD 5 m pulley belt. Finding the deck too flexible to mount the battery pack under, [doublecloverleaf] strengthened it with a pair of carbon-fiber tubes bracketed on the underside. A few custom PCB boards connect ten 5 Ah LiPo battery cells in series to create two, five-cell packs which are kept safe by a thick housing mounted between the board’s trucks. [doublecloverleaf] calculates that they could make up to a 15 km trip on a single charge.

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Musical Proximity Detection Pet Bowls

August 29, 2016 by 2 Comments

An essential skill for a maker is the ability to improvise or re-purpose existing materials into new parts. Sometimes, one needn’t make many modifications to create something new, as is the case with [Robin Sterling] and his musical pet bowl.

Originally, it was a sealed pet bowl that opened when the proximity sensors detected an approaching pet. Having helped design the bowl, [Sterling] had a bit of an advantage when he decided to convert it into a theremin/light harp-esque instrument for the company BBQ. He routed the PWM outputs from each of the three proximity sensors (in each of the three bowls) to a small guitar amp, adjusting each sensor’s output to a different frequency. Despite the short amount of time [Sterling] had to practice, it works fairly well!

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Exoskeleton Designed For Children

August 25, 2016 by 4 Comments

Exoskeletons are demonstrably awesome, allowing humans to accomplish feats of strength beyond their normal capacity. The future is bright for the technology — not just for industrial and military applications, but especially in therapy and rehabilitation. Normally, one thinks of adults who have lost function in their limbs, but in the case of this exoskeleton, developed by The Spanish National Research Council (CSIC), children with spinal muscular atrophy are given a chance to lead an active life.

Designing prosthetics for children can be difficult since they are constantly growing, and CSIC’s is designed to be telescopic to accommodate patients between the ages 3-14. Five motors in each leg adapt to the individual symptoms of the patient through sensors which detect the child’s intent to move and simulates what would be their natural walking gait.

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Hoverchair For Your Hoverboard Turns Your Segway Into A Go-Kart

August 25, 2016 by 17 Comments

Want to get somewhere safely, but all you have is a Segway? An afternoon spent tinkering can turn your Segway into a lounging cruiser with this hoverseat attachment, just like YouTuber [Inflatable Boats]’s hot new ride.

The backbone of the cart is the Segway Mini Pro. An aluminium frame attaches to the Segway via an eye-bolt and two carabiners, the larger of which has some tape wrapped around it to reduce wear. A swivel caster is attached with u-bolts to support the weight  of the rider along the middle of this makeshift go-cart. Pushing on a t-handle made of pvc — connected to the Segway’s knee brace with a simple strap — engages the motor in lieu of the normal lean-to-go-forward action. Turning is simply done by swinging the handle or pressing with your feet.

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Compact EPaper Business Card

August 23, 2016 by 39 Comments

Is your business card flashy? Is it useful in a pinch? Do they cost $32 each and come with an ePaper display? No? Well, then feast your eyes on this over-the-top business card with an ePaper display by [Paul Schow]. Looking to keep busy and challenge himself with a low-power circuit in a small package, he set about making a business card that can be updated every couple of months instead of buying a new stack whenever he updated his information.

Having worked with ePaper before, it seemed to be the go-to option for [Schow] in fulfilling the ultra-low power criteria of his project — eventually deciding on a 2″ display. Also looking to execute this project at speed, he designed the board in KiCad over a few hours after cutting it down to simply the power control, the 40-pin connector and a handful of resistors and capacitors. In this case, haste made waste in the shape of the incorrect orientation of the 40-pin connector and a few other mistakes besides. Version 2.0, however, came together as a perfect proof-of-concept, while 3.0 looks sleek and professional.

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