Air Quality Monitor Plays Game Of Life

The problem with air quality is that you can’t really tell how good or bad it is just by looking…unless it’s really bad, that is. It’s usually more helpful to have some kind of sensor that can tell you what the deal is. To that end, [Arnov Sharma] built a neat air quality monitor with a fun twist.

A Raspberry Pi Pico W acts as the heart of the build, armed with an SGP40 gas sensor. This sensor is intended for monitoring total volatile organic compounds in the air, which can be a useful measure of air quality in at least one dimension. It reports a simple air quality score from 0 to 500, based on a 1-1000 ppm ethanol equivalent reading. Based on the sensor’s output, the Pi Pico drives an LED matrix display — setting it green for good quality air, yellow for moderate, and red for poor air quality (i.e. high VOC content). The fun part is that rather than just show a simple color, the display plays Conway’s Game of Life to create an animated visual. We’d love it even more if poor air quality lead to the premature death of individual cells, making it even more interactive.

We’ve featured other air quality monitors before; often, it’s desirable to monitor CO2 levels to determine whether more ventilation is needed.

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Smart Home Gets A Custom Keypad Controller

Voice assistants and smartphones are often the go-to interfaces for modern smart home systems. However, if you fancy more direct physical controls, you can go that route as well. To that end, [Salim Benbouziyane] whipped up a nifty keypad to work with his Home Assistant setup.

The build is based on an ESP32 microcontroller, which has wireless hardware onboard to communicate with the rest of [Salim’s] Home Assistant setup. Using the ESPHome firmware framework as a base, the microcontroller is connected to a four-by-three button keypad array, built using nice clicky key switches. There’s also an indicator light on top as a system status indicator. A fingerprint scanner provides an easy way for users to authenticate when disarming the alarm.

Security and speed were the push for [Salim] to whip up this system. He found it difficult to disarm his alarm in a hurry when fumbling with his phone, and the direct keypad entry method was far more desirable.

Sometimes, the easiest route to the smart home of your dreams is to just build the exact solutions you need. Video after the break.

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Franke A600 coffee machine with PicoVoice

Coffee By Command: The Speech2Touch Voice Hack

If you were to troll your colleagues, you can label your office coffee maker any day with a sticker that says ‘voice activated’. Now [edholmes2232] made it actually come true. With Speech2Touch, he grafts voice control onto a Franke A600 coffee machine using an STM32WB55 USB dongle and some clever firmware hacking.

The office coffee machine has been a suspect for hacking for years and years. Nearly 35 years ago, at Cambridge University, a webcam served a live view of the office coffee pot. It made sure nobody made the trip to the coffee pot for nothing. The funny, but in fact useless HTTP status 418 was brought to life to state that the addressed server using the protocol was in fact a teapot, in answer to its refusal to brew coffee. Enter this hack – that could help you to coffee by shouting from your desk – if only your arms were long enough to hold your coffee cup in place.

Back to the details. The machine itself doesn’t support USB keyboards, but does accept a USB mouse, most likely as a last resort in case the touchscreen becomes irresponsive. That loophole is enough: by emulating touchscreen HID packets instead of mouse movement, the hack avoids clunky cursors and delivers a slick ‘sci-fi’ experience. The STM32 listens through an INMP441 MEMS mic, hands speech recognition to Picovoice, and then translates voice commands straight into touch inputs. Next, simply speaking to it taps the buttons for you.

It’s a neat example of sidestepping SDK lock-in. No reverse-engineering of the machine’s firmware, no shady soldering inside. Instead, it’s USB-level mischief, modular enough that the same trick could power voice control on other touchscreen-only appliances.

Automatic Feeder Keeps Fish Sated

[Noisy Electrons] is a maker who also likes to keep fish. He sometimes needs to travel and keep his fish fed in the meantime, so he created an automated solution to handle that for him.

The build is based around an STM32 microcontroller, paired with a MCP7940N real-time clock to keep time. The microcontroller is hooked up to a few buttons and a small display to serve as an interface, allowing the feeding times and dosage amounts to be configured right on the device. Food is distributed from a 3D printed drum with a hole in it, which is rotated via a stepper motor.  Each time the drum rotates, some food falls through the hole and into the tank. Dosage amount is measured in rotations — the more times the drum rotates, the more food is delivered to the fish.

[Noisy Electron] built three of these devices for three separate tanks. Thus far, it’s been three weeks and all the fish are still alive, so we’ll take that as a vote of confidence in the build. We’ve featured some other great pet feeders over the years, too Continue reading “Automatic Feeder Keeps Fish Sated”

Spinning Top Chair Revisited

Designer furniture generally comes with excellent aesthetics and (sometimes) functionality. However, such furniture comes with a price to match. One such piece of furniture is the Magis Spun Chair. It’s a striking piece with a fun party trick to match: it works like a top spinning while you sit inside. However, it has a prohibitively expensive price tag of $1,200 to match. That’s why [Morley Kert] is on a mission to build one for less. 

This isn’t [Morley]’s first time building a spinning chair. The first attempt featured numerous 3D printed pieces glued together. It did not inspire confidence in spinning, nor was it a striking piece of furniture. So a revisit was in order.

This time around the chair’s construction was CNC milled plywood. Some surfaces featured 3D carving, but the majority were left raw with carving the final shape handled manually. Despite its size, the chair only took four and a half sheets of 3/4 inch plywood by hollowing out the base allowing for more efficient use of material. Once the router had completed the pieces, they were stacked and glued together. Each layer was aligned with hidden dowels making the assembly process fairly straightforward.

However, while usable, the chair looked rather unfinished, so [Morley] went to town on it with a power carving angle grinder. To ensure even carving on the circular profile of the chair, he placed it, or for some sections glued it, on an electronic lazy Susan. After some practice, the carving process turned out really well with a well-shaped and professional looking chair. Some wood varnish and a large amount of sanding finished up the chair very nicely for a total material cost of under $500.

We were happy to see the completion of this chair building saga. If you want to see [Morley] make even more designer furniture for cheap, make sure to check out his other 3D printed chair!

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Hexagonal Lighting Brings A Touch Of Elegance To The Workshop

Sometimes, we’re faced with what should be simple household tasks that we choose to make more difficult. Sure, you could buy a clock, hang it on your wall, and move on with your day, or could spend a week or two building the perfect one. [Nejc Koncan] was in one such situation recently when he needed some new overhead lighting. He wanted hexagonal lights — and since none of the off-the-shelf solutions met his exacting requirements, he built his own.

Unlike most of the cycling RGB hexagonal lighting solutions available on the market, [Nejc] wanted elegant white outlines that he could control via HomeAssistant. After some careful design and quite a bit of trial-and-error, he ended up with a highly modular and very professional-looking installation. The hexagons are constructed from LED strips set into aluminum extrusions, with junction PCBs at each intersection. To complete the look, all of the strips and wiring are hidden by diffusers that slot into the extrusions — and of course, the whole thing is open source.

We see lots of lighting projects here at Hackaday, and even other hexagonal lights — but this might just be one of the most refined. Sometimes it’s worth the extra effort to build a totally over-engineered custom solution.

This image created using GPT-4o on Poe using the prompt “picture of an upright freezer connected to a computer for temperature monitoring, together with a graph and an alarm siren. Suitable for a professional blog. Be humorous and use a vintage theme.”

Freezer Monitoring: Because Ice Cream Is A Dish Best Served Cold

[Scott Baker] wrote in to let us know about his freezer monitor.

After a regrettable incident where the ice cream melted because the freezer failed [Scott] decided that what was called for was a monitoring and alerting system. We enjoyed reading about this hack, and we’ll give you the details in just a tick, but before we do, we wanted to mention [Scott]’s justifications for why he decided to roll his own solution for this, rather than just using the bundled proprietary service from the white goods manufacturer.

We’re always looking for good excuses for rolling our own systems, and [Scott]’s list is comprehensive: no closed-source, no-api cloud service required, can log with high fidelity, unlimited data retention, correlation with other data possible, control over alerting criteria, choice of alerting channels. Sounds fair enough to us!

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