Smokeless Burn Barrel Makes Your Backyard Fire Much Cleaner

October 21, 2021 by Lewin Day 80 Comments

Old 55-gallon drums are often repurposed into fire barrels with the simple addition of a few holes cut into the walls. Generally, they’re fit enough for purpose but can have a very smoky output, particularly when overloaded. However, this design from [Building Stuff Is Fun] combines two drums into one to create a barrel that burns far more efficiently with less smoke! (Video, embedded below.)

Note the vent holes feeding oxygen to the fire just before the barrel outlet.

Through some clever cuts and folding of steel, a single burn barrel is created from the original two that helps eliminate smoke entirely, through two clever design features. First of all, plentiful air is provided to the fire thanks to the intakes at the bottom of the barrel. Secondly, the barrel-in-barrel design, paired with some smart vents, helps provide fresh air to the fire just before it leaves the barrel. This extra oxygen supply helps create secondary combustion at the outlet which burns up all the matter that would normally be passed out as smoke.

The design involves a lot more work than just hacking some holes in an old drum, but the results are undeniably impressive. The output of the smokeless burn barrel looks far hotter and cleaner. We’ve seen similar designs used to supply workshop heat, too. Video after the break.

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Build A Dog Ball Launcher That Kinda Looks Like A Dog

October 18, 2021 by Lewin Day 12 Comments

The average garden dog will play fetch long beyond the average human’s endurance. If you want to keep your dog exercised without hurting your pitching arm, [brankly’s] automatic dog ball launcher might just be what you need.

The design is straightforward. The 3D printed housing features a large funnel into which a ball can be dropped. A servo then holds the ball while a pair of rollers are spun up by brushed DC motors. After two seconds, the servo releases the ball towards the rollers which launch the ball out of the machine. A Raspberry Pi Pico runs the show, controlling the timing of the ball launch and varying the motor speed to change the distance the ball is launched on each firing.

Files are available on Thingiverse for those eager to build their own. If you’re good, you might even be able to train your dog to drop the ball in themselves. We’ve seen similar builds before, too! Video after the break.

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Fail Of The Week: Magnetic Levitation

October 16, 2021 by Al Williams 26 Comments

We are big fans of the little desktop magnetic levitation setups that float a small object on a magnet. As [3D Printed Life] points out, they look like magic. He was surprised that the commercial units use analog electronics. He decided to build a digital version but didn’t know what he was getting into. He details his journey in the video you can see below.

Along with a custom control board, he decided to wind his own electromagnets. After finding that tedious he built a simple coil winder to automate some of the work.

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Unique Seven-Segment Display Relies On FR-4 Fluorescence

October 16, 2021 by Dan Maloney 11 Comments

It’s interesting what you see when you train a black light on everyday objects. We strongly suggest not doing this in a hotel room, but if you shine UV light on, say, a printed circuit board, you might see what [Sam Ettinger] did, which led him to build these cool low-profile seven-segment fluorescent PCB displays.

As it turns out, at least some FR-4 PCBs fluoresce under UV light, giving off a ghostly blue-green glow. Seeing the possibilities, [Sam] designed a PCB with cutouts in the copper and solder mask in the shape of a traditional seven-segment display. The backside of the PCB has pads for UV LEDs and current-limiting resistors, which shine through the board and induce the segments to glow. Through-slots between the segments keep light from one segment from bleeding over into the next; while [Sam] left the slots unfilled, they could easily be filled with solder. The fluorescent property of FR-4, and therefore the brightness and tint of the segments, seems to vary by board thickness and PCB manufacturer, but it looks like most PCBs will show pretty good results.

We’d say the obvious first improvement might be to cover the back of the display with black epoxy, to keep stray light down, and to improve contrast. But they look pretty great just as they are. We can also see how displays with other shapes, like icons and simple symbols. Or maybe even alphanumeric characters — say, haven’t we seen something like that before?

Here’s A 100 MHz Pin-Compatible 6502 Replacement

October 15, 2021 by Lewin Day 94 Comments

The MOS Technology 6502 CPU was a popular part in its day. In various modified versions, it powered everything from the Commodore 64 to the Nintendo Entertainment System, and showed up in a million other applications too. A popular variant is the 65C02, and [Jürgen] decided to whip up a pin-compatible FPGA version that runs at a blazing 100MHz.

The CPU core was borrowed from work by [Arlet Ottens] and extended with 65C02 functionality by [Ed Spittles] and [David Banks]. [Jürgen] then packaged that core in a Spartan-6 FPGA and placed it on a small PCB the size of the original 65C02’s 40-pin dual inline package.

The FPGA is set up to access the external CPU bus with the timing matched to the clock of the host machine. However, internally, the CPU core runs at 100MHz. It copies RAM and ROM from the host machine into its own internal 64 kilobyte RAM, minus the areas used for memory-mapped I/O by the host. The CPU then runs at full 100MHz speed except when it needs to talk to those I/O addresses.

It allows the chip to accelerate plenty of tasks without completely flipping out when used with older hardware that can’t run at anywhere near 100MHz. The pin-compatible design has been tested successfully in an Apple II and a Commodore 8032, as well as a variety of vintage chess computers.

We’ve seen the opposite before too, with a real 6502 paired with a FPGA acting as the rest of the computer. If you’ve got any cutting-edge 6502 hacks of your own (not a misprint!), let us know!

[Thanks to David Palmer for the tip]

Electroplating Carbon Fibers Can Have Interesting Results

October 15, 2021 by Lewin Day 17 Comments

Typically, electroplating is used to put coatings of one metal upon another, often for reasons of corrosion protection or to reduce wear. However, other conductive materials can be electroplated, as demonstrated by [Michaɫ Baran].

Finer details are sparse, but [Michaɫ’s] images show the basic concept behind producing a composite metal material hand sculpture. The initial steps involve 3D printing a perforated plastic shell of a hand, and stuffing it with carbon fibers. It appears some kind of plastic balls are also used in order to help fill out the space inside the hand mold.

Then, it’s a simple matter of dunking the plastic hand in a solution for what appears to be copper electroplating, with the carbon fiber hooked up as one of the electrodes. The carbon fibers are then knitted together by the copper attached by the electroplating process. The mold can then be cut away, and the plastic filling removed, and a metal composite hand is all that’s left.

[Michaɫ] has experimented with other forms too, but the basic concept is that these conductive fibers can readily be stuffed into molds or held in various shapes, and then coated with metal. We’d love to see the results more closely to determine the strength and usefulness of the material.

Similar techniques can be used to strengthen 3D printed parts, too. If you’ve got your own ideas on how to best use this technique, sound off below. If you’ve already done it, though, do drop us a line!

[Thanks to Krzysztof for the tip]

Hack Your Sodastream With A Giant CO2 Canister

October 14, 2021 by Lewin Day 111 Comments

Sodastream machines are popular amongst people who like to make their own seltzer water at home. However, replenishing the tiny gas canisters is expensive and wasteful. [Becky] decided to upgrade her machine to avoid this problem, and added some smarts while she was at it.

The simple part of the hack is using an adapter to connect the Sodastream apparatus to a 50 lb CO2 tank from the welding store. This is easy enough, and just uses a off the shelf adapter. Using welding-grade gas in your drinking water is probably a really bad idea, but [Becky] was willing to take the nisk.

However, safety was given due attention in that a CO2 monitor was installed to make [Becky] aware of any dangerous leaks. The tank is also placed on a custom scale built with load cells and an ESP8266, which allows monitoring of how much gas is left. [Becky] notes that at her rate of drinking one bottle a day, the tank should last her a full 7 years or so.

The project brings costs down to 18 cents per liter of seltzer, versus 38 cents for the Sodastream gas supply. It’s likely that the Sodastream prices could still be beat even if a food-safe CO2 source was used. Plus, there’s no need to regularly buy new bottles!

Overall, it’s a great project and one that recalls us of continuous-ink printer hacks. Video after the break.

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