This WiFi Signal Strength Meter Ain’t Afraid Of No Ghosts

December 23, 2022 by Dan Maloney 5 Comments

The original Ghostbusters movie is a classic that’s still delivering nearly 40 years after its release — just let that sink in for a minute. Almost every aspect of the film, from hand props to quotes, is instantly recognizable, even to people who haven’t based their lives on the teachings of [Venkman], [Stantz], and [Spengler]. To wit, we present this PKE meter-style WiFi scanner.

Of course, [Kevin McAleer]’s project is strictly in the “Just for Fun” category. But that doesn’t mean it’s not at least somewhat useful. The design is pretty close to the original PKE meter, with a little bit of creative license taken to make it easier to build. Guts include a Raspberry Pi Pico W and a generous 320×240 LCD display. The body of the meter is entirely 3D printed; design files are of course available. The meter’s arms are geared together to move with a single hobby servo.

On the software side, [Kevin]’s GUI lets users see a list of WiFi hotspots in the area and select one from the list. From there, the position of the arms is determined by the RSSI for the hotspot, similar to how the prop was supposed to indicate the proximity to a spook, specter, or ghost. There’s perhaps a bit of a missed opportunity by not adding LEDs to the arms, but we’ll let that slide.

The video below has full design and build details, but fair warning that it’s a bit on the long side. That’s probably just a reflection of how much work [Kevin] put into this, though. Of course, you may rather build a PKE meter that “actually” detects ghosts, in which case we’ve got you covered.

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More Detail On That Fantastic Lego OLED Brick

December 20, 2022 by Dan Maloney 39 Comments

It’s always great when we get a chance to follow up on a previous project with more information, or further developments. So we’re happy that [“Ancient” James Brown] just dropped a new video showing the assembly of his Lego brick with a tiny OLED screen inside it. The readers are too, apparently — we got at least half a dozen tips on this one.

We’ve got to admit that this one’s a real treat, with a host of interesting skills on display. Our previous coverage on these bedazzled bricks was disappointingly thin on details, and now the original tweets even seem to have disappeared entirely. In case you didn’t catch the original post, [James] found a way to embed a microcontroller and a remarkably small OLED screen into a Lego-compatible brick — technically a “slope 45 2×2, #3039” — that does a great job of standing in for a tiny computer monitor.

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A Simple High-Fidelity DIY Mic Pre Amp

December 16, 2022 by Lewin Day 13 Comments

If you’re doing any serious work with microphones, you’ll typically find yourself in want of a dedicated preamp. [ojg] needed just such a thing for acoustic measurement duties, and set about working up a cheap DIY design by the name of ThatMicPre.

The design is based around the THAT1510 preamp IC, known for its good frequency response and low harmonic distortion and noise. The design is also compatible with THAT1512, SSM2019, and INA217 chips as well. [ojg] gave the design switch-controlled gain levels, providing greater accuracy than a potentiometer adjustment, and the ability to supply phantom power for mics that require it. The PCB is designed to rely on through-hole parts and common connectors for easy assembly.

The design is open source, and has already been built by others on the DIYAudio forums. Built into a simple case, it looks like a handsome and well-built piece of audio equipment. We’ve featured quite a few unique preamps over the years, and if you’ve been building your own, we’d love to see those too!

Crazy Bike Frame Made Out Of 147 Nuts

November 16, 2022 by Lewin Day 39 Comments

Bike frames are most commonly made out of steel. If you’ve got money for something nicer though, you might go with something in aluminium or carbon fiber. [The Q] went completely off-the-wall with this build, though, constructing a bicycle frame out of 147 nuts.

Yes, a variety of nuts in various sizes were laid out and welded together to make the frame. The overall layout is a conventional diamond frame, albeit constructed out of many nuts stuck together rather than with tubes. Notably though, several important areas aren’t made in this way. The front and rear dropouts are made of sheet steel, and the bottom bracket, seat post mount, and headstem are all made of steel tube. After welding, the bike was given an attractive coat of grey paint. It was then laced up with the usual running gear and given a set of chunky mountain bike tires.

We wouldn’t want to push this frame too hard over bumps and jumps. The video only shows the nuts being joined with tack welds, and the front forks look particularly fragile. One suspects a decent shock loading could snap parts of the frame apart. Overall, though, it’s an eye-catching bike that has plenty of easy places to attach a lock. For an ultra-fashionable city-bound cruiser, it would be hard to beat.

We’ve featured some weird and wonderful bikes over the years, including this tasteful plywood design. Video after the break.

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Circadian Lighting For The Home Via Home Assistant

November 13, 2022 by Lewin Day 10 Comments

Artificial lighting is great, in that it lets us work and live well into the night. However, our bodies are dependent on the natural lighting cycles of the sun as part of their basic operation, and artificial lighting can interfere with this. [Tyler Cipriani] decided to use Home Assistant with some smart lights to try and make home lighting more suitable for our natural circadian rhythms.

The basic intent was to give the home bright white/blueish light during the day, matching the sun’s output. The light would then be altered to warmer yellow/red tones in the evening. The eye has cells that respond to blue light to regulate our circadian rhythms with the presence of the sun, so reducing blue light at night may help reduce disruption to sleep and other body processes.

Home Assistant has a Circadian lighting component available built specifically for this task. It’s a useful smart home tool for achieving such a job, too, as it readily works with a wide variety of hardware from different vendors. In [Tyler]’s case, light switches are Zigbee devices that talk to Home Assistant via a Zigbee2MQTT hookup and a Combee Zigbee gateway. Lights around the home are a mixture of Philips Hue devices and other brands of smart lights.

[Tyler] states the effects are “subtle but noticable.” He notes that it’s easier to feel sharp and work during the day, but harder to continue the lighting warms and dims at night. He points out that this is a design feature to help keep him on a healthy sleep schedule.

We’ve seen other circadian rhythm lights before. In fact, NASA uses them on the ISS, but you can build your own for a lot less than they spent. If you’ve got your own circadian lighting hacks, don’t hesitate to drop us a line!

Protect Your Property With This Fire-Breathing Billionaire

November 12, 2022 by Dan Maloney 16 Comments

Let’s face it: if you can’t trust a fire-breathing billionaire industrialist to protect your stuff, who can you trust? (Video, embedded below.)

This one is straight out of the Really Bad Ideas™ files, and comes to us from [Marc Radinovic]. His story on this one is that he wants to protect the stuff in his new house, and felt that a face-recognition system with a flame thrower would be the best way to address that. And to somehow make it even better, said system would be built into a ridiculous portrait of everyone’s favorite plutocrat. The guts of the system are pretty much what you’d expect — a camera and a Raspberry Pi running OpenCV and a face recognition library, a butane reservoir and a solenoid valve, an arc lighter as an ignition source, and an Arduino and some completely not sketchy at all wiring to control all pieces. And LCD displays for [Elon]’s eyes, of course.

The system is trained to recognize [Marc]’s face and greets him cheerfully when he’s in view. [Non-Marc] people, however, are treated a bit less accommodatingly, up to and including a face-melting fireball. Effigies of other billionaires got the treatment; strangely, [Marc]’s face-recognition algorithm didn’t even recognize another [Mark] as a human face, which when you think about it is pretty darn funny.

So, certainly not a practical security system, and definitely not something you should build, but it’s pretty good fun anyway. It reminds us a bit of the fire-breathing duck we saw years ago.

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The Seven-Segment Display That’s Also An Input Device

November 5, 2022 by Dan Maloney 1 Comment

We’re used to seeing all manner of seven-segment displays, be they mechanical, electronic, or something in between. But what all these displays have in common is that they’re, you know, displays. Using them as inputs would just be crazy talk, right?

Perhaps, but we like where [Dave Ehnebuske] is going with “InSlide,” the seven-segment input device. The idea for this comes from the “DigiTag” display, which we covered back in October, and divides a standard seven-segment character into three vertical strips — two skinny ones for the outside vertical segments, and one wide strip holding the horizontal elements. By sliding these strips up and down relative to each other, the standard nine digits, plus a few other characters, can be composed.

[Dave]’s take on this theme started by building his display from laser-cut plywood pieces, which is a nice choice because of the good contrast between the white wood and the engraver segments. Next, he embedded rare earth magnets in the slides and installed seven Hall effect sensors in the frame. The sensors are connected to an Arduino Nano via a 74HC165 parallel-load shift register, which lets multiple modules be daisy-chained together. He also built an Arduino library to read the current state of the segments; it supports the full hexadecimal character set, or even duodecimal if you like.

[Dave] has shared the library, and it looks like you can get the build files for the mechanism from the original project. That’s good, because this looks ripe for hacking. It looks like it would be pretty easy to motorize a display like this by adding rack-and-pinion gearing and steppers — something like that could make an interesting clock.