Author Archives: Kristina Panos

Finding Noise with an Antenna

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[K5ACL], aka [SignalSearch], recently brought his active receive loop antenna in off the roof to give it a checkup and perform any necessary maintenance. While it was in the shack, he took the opportunity to discuss how well it would perform indoors. The verdict? Not ideal. He’d mount it 50 feet away from the house if the HOA would let him.

Houses, and subsequently most ham shacks, are filled with noise sources that interfere badly with HF. So after spending a minute or so listening on an SDR, [K5ACL] demonstrates another use for this type of tightly-tuned antenna—as a noise …read more

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Pinging the Depths of a Rain Barrel

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Rain barrels are a great way to go green, as long as your neighborhood doesn’t frown upon them. [NikonUser]’s barrel sits up high enough that he has to climb up on an old BBQ and half-dangle from the pipe to check the water level, all the while at the risk of encountering Australian spiders.

Arachnophobia, it turns out, is a great motivator. At first, [NikonUser] dreamed up a solar-powered IoT doodad that would check the level and report the result on a web page. He battled the Feature Creep and decided to build a handheld device that pings the water …read more

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Pinging the Depths of a Rain Barrel

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Rain barrels are a great way to go green, as long as your neighborhood doesn’t frown upon them. [NikonUser]’s barrel sits up high enough that he has to climb up on an old BBQ and half-dangle from the pipe to check the water level, all the while at the risk of encountering Australian spiders.

Arachnophobia, it turns out, is a great motivator. At first, [NikonUser] dreamed up a solar-powered IoT doodad that would check the level and report the result on a web page. He battled the Feature Creep and decided to build a handheld device that pings the water …read more

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Mechanisms: The Reed Switch

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Just about everywhere you go, there’s a reed switch nearby that’s quietly going about its work. Reed switches are so ubiquitous that you’re probably never more than a few feet away from one at any given time, especially at home or in the car. You might have them on your doors and windows as part of a burglar alarm system. They keep your washing machine from running when the lid is open, and they put your laptop to sleep when you close the lid. They know if the car has enough brake fluid and whether or not your seat belt …read more

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Repairs You Can Print Contest: Meet the Winners

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Six weeks ago, we asked you to show us your best 3D printed repairs for a chance to win $100 in Tindie credit and other prizes. You answered the call with fixes for everything from the stuff everyone has, like zippers and remotes, to the more obscure stuff, like amazing microscopes scavenged from dumpsters.

It was hard to whittle down the entries we received into the top 20 because you came up with so many awesome fixes. A few of them had us thinking hard about the definition of repair, but are brilliant in their own way.

So without …read more

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PipeCam: Shallow-Water Exploration with Raspberry Pi

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In what began as a personal challenge he issued to himself, [Fred] is in the process of building an underwater camera that’s capable of long-term photography in shallow waters. He’d like it to last about five hours on a charge while taking a photo every five minutes. Ideally, it will be as cheap as possible and constructed from readily available parts. Solving the cheap/available equation would theoretically make the camera easily to replicate, which is the third major requirement.

[Fred] has recently made great strides, both in the circuitry and the capsule design. The latest version uses a Raspberry Pi …read more

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Definitive Dog Feeding with Arduino

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Some dogs have no sense of self-preservation. Given the opportunity, they will eat until they’re sick. It’s up to us humans to both feed them and remember doing it so they aren’t accidentally overfed. In a busy household with young children, the tricky part is the remembering.

[Bryan]’s family feeds their dog Chloe once a day, in the mornings. She was a rescue who spent a few years scrounging for meals on the street, so some part of her is always interested in finding food, even if she just ate. Each morning, the flurry of activity throughout the house is …read more

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DIY Peristaltic Pump Keeps the Booze Flowing

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A few months ago we showed you a bar bot built by [GreatScott] that uses peristaltic pumps to food-safely move the various spirits and mixers around behind the curtain. The bar bot uses three of them, and at $30 each for pumps with decent flow rate, they added a lot to the parts bill. These pumps are pretty much the ideal choice for a bar bot, so what do you do? [GreatScott] decided to see if it was worth it to make them instead.

Peristaltic pumps are simple devices that pump liquids without touching them. A motor turns a set …read more

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Vera Rubin: Shedding Light on Dark Matter

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Vera sat hunched in the alcove at Kitt Peak observatory, poring over punch cards. The data was the same as it had been at Lowell, at Palomar, and every other telescope she’d peered through in her feverish race to collect the orbital velocities of stars in Andromeda. Although the data was perfectly clear, the problem it posed was puzzling. If the stars at the edges of spiral galaxy were moving as fast as the ones in the center, but the pull of gravity was weaker, how did they keep from flying off? The only possible answer was that Andromeda contained …read more

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Repairs You Can Print: Floor Lamp is Now Several Shades Better

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We all have that one possession—maybe more than one—that we’ve had forever and refuse to let go of, even though it has seen better days. When that something is a useful appliance, it can be heartbreaking to watch it deteriorate. For [Elmojo], that thing is a 10+ year old Medusa-style floor lamp. It still looks and works great, but the plastic shades are crumbling. The good news: [Elmojo] has a 3D printer.

Here’s where things get exciting. Not only did [Elmojo] have a pretty good chance of making new shades that would work, he had a chance to change the …read more

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