This MDF Sound Bar Sounds Great

July 3, 2019 by Brian Benchoff 12 Comments

Everyone should build a speaker cabinet at least once in their life, if only so they can realize how much thought goes into building a simple box. [John] of ibuildit.ca wanted a sound bar for his home theater setup, and that means building a sound bar. The result is beautiful, and a demonstration of how much you can do with just a router and a table saw.

[John] built this sound bar almost entirely out of MDF, which isn’t the best material but it works well enough for a speaker cab that’s meant to be mounted to a wall. The sides were constructed first, with a rabbet holding the front and back on. Both the woofer and tweeter are inset into the front, and a standard piece of plumbing pipe serves as the bass port. Slap a round over bit into the router and do some light sanding, and everything looks great with a coat of black paint.

As with any speaker enclosure, the design is effectively parametric, designed entirely around the drivers being used. In this case, [John] is using a spreadsheet named ‘Unibox’ that gives you all the formulas and graphs for designing a speaker enclosure.

With the box built and the speakers installed, the only matter left were a few aesthetic choices. [John] went with a standard black finish with a very nice wooden grille held onto the front with magnets. It’s a design that pops, but the true test of a speaker is how it sounds. That’s a bit hard to convey over the Internet, but [John] included a few sound samples at the end of the build video, available below.

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Ramen Lamp Has Us Feeling Hungry

July 2, 2019 by Zoe Skyforest 7 Comments

Ramen comes in many forms, and whether you’re eating the 10 cent instant packets during the school year, or dining out at a fancy noodle bar, it’s a tasty meal either way. [ramenkingandi] has long been in love with the classic Japanese fare, and decided to create a homage to the dish – in lamp form.

The lamp build begins, somewhat unsurprisingly, with a lamp – but not how you’d think. A Walmart floor lamp is harvested for its lampshade, which approximates the dimensions of a typical ramen bowl. It’s then fitted with warm yellow LEDs to give it a pleasing glow. Polymer clay is used to create fake ramen ingredients – including noodles, pork, and choy sum. Jewelery wire is used to suspend the chopsticks in mid-air, before resin is poured into the bowl and the ingredients arranged on top. For a final touch, the bowl is painted with an artistic stripe to hide the electronics inside, and the lamp is complete.

It’s a great example of fake Japanese food, which is actually a huge industry in that part of the world. We’d love to have this lamp on display in our own home, fully expecting ramen consumption to increase considerably over time.

Lamps are a common feature around these parts – and some of them have even learned to leap.

AI Recognizes And Locks Out Murder Cats

July 1, 2019 by Dan Maloney 56 Comments

Anyone with a cat knows that the little purring ball of fluff in your lap is one tiny step away from turning into a bloodthirsty serial killer. Give kitty half a chance and something small and defenseless is going to meet a slow, painful end. And your little killer is as likely as not to show off its handiwork by bringing home its victim – “Look what I did for you, human! Are you not proud?”

As useful as a murder-cat can be, dragging the bodies home for you to deal with can be – inconvenient. To thwart his adorable serial killer [Metric], Amazon engineer [Ben Hamm] turned to an AI system to lock his prey-laden cat out of the house. [Metric] comes and goes as he pleases through a cat flap, which thanks to a solenoid and an Arduino is now lockable. The decision to block entrance to [Metric] is based on an Amazon AWS DeepLens AI camera, which watches the approach to the cat flap. [Ben] trained three models: one to determine if [Metric] was in the scene, one to determine whether he’s coming or going, and one to see if he’s alone or accompanied by a lifeless friend, in which case he’s locked out for 15 minutes and an automatic donation is made to the Audubon Society – that last bit is pure genius. The video below is a brief but hilarious summary of the project for an audience in Seattle that really seems quite amused by the whole thing.

So your cat isn’t quite the murder fiend that [Metric] is? An RFID-based cat door might suit your needs better.

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Trick Shot Bot Flings Balls Into Wine Glass Every Time

June 26, 2019 by Dan Maloney 7 Comments

We’ve heard of beer pong, but we’re not sure we’ve heard of wine pong. And certainly never wine pong automated with a ping pong ball throwing robot like this one.

There’s not a huge amount of detail available in the video below, and no build log per se. But [Electron Dust] has a few shots in the video that explain what’s going on, as well as a brief description in a reddit thread about the device. The idea is to spin a ball up to a steady speed and release it the same way every time. The rig itself is made of wood and spun by plain brushed DC motors – [Electron Dust] explains that he chose them over PWM servos to simplify things and eliminate uncertainty in the release point. The ball is retained by a pair of arms, each controlled by a pair of hobby servos. An Arduino spins along with everything else and counts 50 revolutions before triggering the servos to retract and release the ball. A glass positioned at the landing spot captures the ball perfectly once everything is dialed in.

Here’s hoping that build details end up on his blog soon, as they did for this audio-feedback juggling machine. And while we certainly like this project, it might be cool if it could aim the ball into the glass. Or it could always reposition the target on the fly.

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Dry Your Boots With The Internet Of Things

June 24, 2019 by Zoe Skyforest 16 Comments

If you live somewhere cold, where the rain, snow and slush don’t abate for weeks at a time, you’ve probably dealt with wet boots. On top of the obvious discomfort, this can lead to problems with mold and cause blisters during extended wear. For this reason, boot dryers exist. [mark] had a MaxxDry model that had a timer, but it wasn’t quite working the way he desired. Naturally, it was begging to be hooked up to the Internet of Things.

The brains of the dryer is an ESP32, a solid choice for such a project. With WiFi on board, connecting the device to the internet is a snap. Relays are used to control the fan and heater inside the boot dryer, while MQTT helps make the device controllable remotely. It can be manually switched on and off, or controlled to always switch on at a certain time of the day.

It’s a simple project that shows how easily a device can be Internet controlled with modern hardware. For the price of a cheap devboard and a couple of relays, [mark] now has a more functional dryer, and toasty feet to boot.

We don’t see a lot of boot hacks here, but this magnet-equipped footwear is quite impressive.

Banana Bomb Is Likely To Get You In Trouble

June 22, 2019 by Zoe Skyforest 21 Comments

If there’s one thing Hollywood loves, it’s a ticking clock to create drama. Nuclear weapons, terrorist bombs, and all manner of other devices have been seen featuring foreboding numbers counting down on a series of 7-segment displays. In this vein, [deshipu] developed a rather ridiculous take on the classic trope.

The project is built around a ticking four-digit display. The blue LEDs give it a modern touch, and it’s attached on top of an Arduino Pro Mini 3.3V. This enables the whole module to be powered by a coin cell, for an incredibly compact and tidy timer that is barely bigger than the display itself. There’s also a buzzer attached, which chirps each second, somewhat heightening the stress level in the immediate vicinity.

With a functioning timer, [deshipu] then went for comedy points, by hooking it up to a trio of bananas. This is widely considered more courteous than attaching it to a detonator circuit and actual dynamite, and is key to staying off government watchlists.

It’s a piece that would be amusing at a Halloween party or similar, and is easily completed by any beginner learning Arduino. It goes without saying that, while this is amusing, it’s a build that should very much not be bandied about in public or used for a prank. In this day and age, even touting a custom clock can draw unwelcome attention, so it’s important to be careful. Video after the break.

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Tomorrow Night: HDDG 40, Mechanical And Electronic Ephemera

June 19, 2019 by Brian Benchoff No comments

For the last several years, we’ve hosted a series of meetups for the Bay Area. This week is no different and we’re pleased to announce the fortieth Hardware Developers Didactic Galactic. It’s this Thursday, June 20th, in downtown San Francisco.

The Hardware Developers Didactic Galactic is our monthly IRL meetup, where we ask hardware developers what makes their thing tick. We’ve done dozens of these things, and for those of you in Internet-land, all the talks are available online. Even if you’re not in the Bay Area, all the talks are live streamed. Yes, you too can participate in the event, even if you’re not going to physically attend! It’s an amazing technology called ‘the Internet’ that combines real life with virtual being! It’s like [William Gibson] created some sort of virtual/hyperspace interface.

For this month’s talks, we’ll be joined by Embedded Ninja Shaun Meehan. Shaun has previously given talks that answer the question, what happens when the majority of your work blows up on the Antares space accident? You turn around and get some of your second string units on the next SpaceX launch (9 days later)! Shaun will be talking about his two 300kg robotic arms, FRED & LEFTY, and the project of replacing their 1987 era controllers. This talk includes high power electronics, FPGAs, fixed point algorithms, galvanic isolation, transistor matching, splitting transistors in half, strange position sensors, homemade 3-phase 480 in a garage, and freight LTL shipping.

The live stream for the talks will be available here. Of course, if you can make it to downtown San Francisco (a few blocks south of the Powell Muni/BART stop) we’d be happy to see you. It all goes down Thursday, July 20th, at 6:30 PM.