Compact Sensor Keeps You Safe By Watching CO2 Levels

August 24, 2021 by Dan Maloney 21 Comments

Remember when work meetings were just a bunch of people filling up a small, poorly ventilated room with their exhaled breath? Back in the good old days, all you had to worry about was being lulled to sleep by a combination of the endless slide deck and the accumulation of carbon dioxide. Now? Well, the stakes may just be a little bit higher.

In either situation, knowing the CO₂ level in a room could be a handy data point, which is where a portable CO₂ sensor like this one could be useful. Or at least that’s [KaRMaN]’s justification for SYPHCOM, the “simple yet powerful handheld carbon dioxide meter.” The guts of the sensor are pretty much what you’d expect — an Arduino Pro Micro, a SenseAir S8 CO₂ sensor board, and the necessary battery and charging circuits. But the build does break the mold in a couple of interesting places. One is in the choice of display — a 1980s-era LED matrix display. The HDSP2000 looks like it belongs in a nice bench meter, and is surprisingly legible without a filter. It looks like it flickers a bit in the video below, but chances are that’s just a camera artifact.

The other nice part of this build is the obvious care [KaRMaN] put into making it as small as possible. The layout of boards and components is very clever, making this a solid, compact package, even without an enclosure. We’ve seen CO₂ sensors with more features, but for a quick check on air quality, SYPHCOM looks like a great tool.

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Occam’s Razor: Gardening Edition

August 21, 2021 by Bryan Cockfield 44 Comments

While the impulse to solving problems in complex systems is often to grab a microcontroller and some sensors to automate the problem away, interfacing with the real world is often a lot more difficult than it appears. Measuring soil moisture, for example, seems like it would be an easy way of ensuring plants get the proper amount of water, but soil is a challenging environment for electronics and this solution often causes more problems than it solves. [Kevin] noticed this problem with soil moisture sensors and set about solving this problem with a much simpler, though indirect, method of monitoring his plants electronically.

Rather than relying on soil conductivity for testing soil moisture levels, he has developed an alternate method of determining if the plants need to be watered simply by continuously weighing them. The hypothesis that he had was that a plant that needs water will weigh less as the available water respirates out of the plant or evaporates from the soil. This means that using a reliable sensor like a load cell to measure weight rather than an unreliable one like a soil moisture sensor will result in more reliable data he can use to automate his plants’ watering.

[Kevin]’s build is based around an ESP32 and a commercially-available load cell which are all built into the base of the plant’s pot. The design hides all of the electronics in a pleasant enclosure and is able to communicate relevant info wirelessly as well. The real story here, however, isn’t a novel use of an ESP32 chip, but rather out-of-the-box problem solving by using an atypical sensor to solve this problem. That’s not to say that you can’t ever use other sensors to directly monitor your garden and automate its health, though.

Hacked IKEA Air Quality Sensor Gets Custom PCB

August 13, 2021 by Tom Nardi 19 Comments

Last month we brought word of the IKEA VINDRIKTNING, a $12 USD air quality sensor that could easily be upgraded to log data over the network with the addition of an ESP8266. It only took a couple of wires soldered to the original PCB, and since there was so much free space inside the enclosure, you didn’t even have to worry about fitting the parasitic microcontroller; just tape it to the inside of the case and button it back up.

Now we’ve got nothing against the quick and dirty method around these parts, but if you’re looking for a slightly more tidy VINDRIKTNING modification, then check out this custom PCB designed by [lond]. This ESP-12F board features a AP2202 voltage regulator, Molex PicoBlade connectors, and a clever design that lets it slip right into a free area inside the sensor’s case. The project description says the finished product looks like it was installed from the factory, and we’re inclined to agree.

Nothing has changed on the software side, in fact, the ESP-12F gets flashed with the same firmware [Sören Beye] wrote for the Wemos D1 Mini used in his original modification. That said [lond] designed the circuit so the MCU can be easily reprogrammed with an FTDI cable, so just because you’re leaving the development board behind doesn’t mean you can’t continue to experiment with different firmware builds.

It’s always gratifying to see this kind of community development, whether or not it was intentionally organized. [lond] saw an interesting idea, found a way to improve its execution, and released the result out into the wild for others to benefit from. It wouldn’t be much of a stretch to say that this is exactly the kind of thing Hackaday is here to promote and facilitate, so if you ever find yourself inspired to take on a project by something you saw on these pages, be sure to drop us a line.

ESP8266 Adds WiFi Logging To IKEA’s Air Quality Sensor

July 24, 2021 by Tom Nardi 38 Comments

Introduced back in June, the IKEA VINDRIKTNING is a $12 USD sensor that uses colored LEDs to indicate the relative air quality in your home depending on how many particles it sucks up. Looking to improve on this simplistic interface, [Sören Beye] tacked an ESP8266 to the board so it can broadcast sensor readings out over MQTT.

Just three wires link the ESP8266 to the PCB.

While some of us would have been tempted to gut the VINDRIKTNING and attach its particle sensor directly to the ESP8266, the approach [Sören] has used is actually quite elegant. Rather than replacing IKEA’s electronics, the microcontroller is simply listening in on the UART communications between the sensor and the original controller. This not only preserves the stock functionality of the VINDRIKTNING, but simplifies the code as the ESP doesn’t need to do nearly as much.

All you need to do if you want to perform this modification is solder a couple wires to convenient test pads on the VINDRIKTNING board, then flash the firmware (or write your own version), and you’re good to go. There’s plenty of room inside the case for the ESP8266, though you may want to tape it down so it doesn’t impact air flow.

While not required, [Sören] also recommends making a small modification to the VINDRIKTNING which makes it a bit quieter. Apparently the 5 V fan inside the sensor is occasionally revved up by the original controller, rather than kept at a continuous level that you can mentally tune out. But by attaching the sensor’s fan to the ESP8266’s 3.3 V pin, it will run continuously at a lower speed.

We’ve seen custom firmware for IKEA products before, but this approach, which keeps the device’s functionality intact regardless of what’s been flashed to the secondary microcontroller, is particularly appealing for those of us who can’t seem to keep the gremlins out of our code.

[Thanks to nexgensri for the tip.]

Analog Camera Goes Digital

July 15, 2021 by Bryan Cockfield 33 Comments

The digital camera revolution swept through the world in the early 2000s, and aside from some unique situations and a handful of artists still using film, almost everyone has switched over to digital since then. Unfortunately that means that there’s a lot of high quality film cameras in the world that are gathering dust, but with a few pieces of equipment it’s possible to convert them to digital and get some more use out of them.

[befinitiv]’s latest project handles this conversion by swapping in a Raspberry Pi Zero where the film cartridge would otherwise be inserted into the camera. The Pi is attached to a 3D-printed case which mimics the shape of the film, and also houses a Pi camera right in front of the location where the film would be exposed. By removing the Pi camera’s lens, this new setup is able to take advantage of the analog camera’s optics instead and is able to capture images of relatively decent quality.

There are some perks of using this setup as well, namely that video can be broadcast to this phone over a wireless connection to a computer via the Raspberry Pi. It’s a pretty interesting build with excellent results for a remarkably low price tag, and it would be pretty straightforward to interface the camera’s shutter and other control dials into the Raspberry Pi to further replicate the action of an old film camera. And, if you enjoy [befinitiv]’s projects of bringing old tech into the modern world, be sure to check out his 80s-era DOS laptop which is able to run a modern Linux installation.

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Peeking Inside A Volcano Sensor

July 14, 2021 by Chris Lott 21 Comments

On a recent walk through the Hawaii Volcanoes National Park, [Andrew Cooper] stumbled upon an unlocked monitoring station. Being an engineer, he couldn’t resist taking a look. This station is one of a network of sulfur dioxide (SO2) monitoring stations installed around the park to keep an eye on volcanic emissions. Unsurprisingly, sulfur dioxide is unhealthy to breathe. Sensors like these keep people informed about local conditions before taking their strolls among the volcanic foothills, enjoying gorgeous vistas as [Andrew] describes it.

[Andrew] wasn’t particularly surprised at the contents of the station, since he builds similar equipment in his day job. Continuous power is provided by lead acid batteries kept charged by an array of three mis-matched solar panels. There are duplicate SO2 monitors, an air particulate meter, and a standard weather station affixed to the top. Data is logged on-site and reported up the chain by a cell-phone modem. [Andrew] wasn’t impressed with the workmanship, noting:

It appeared as if the circuits were wired by a ham-handed grad student with no sense of pride in their work.

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Hackaday Links: June 13, 2021

June 13, 2021 by Dan Maloney 6 Comments

When someone offers to write you a check for $5 billion for your company, it seems like a good idea to take it. But in the world of corporate acquisitions and mergers, that’s not always the case, as Altium proved this week when they rebuffed a A$38.50 per share offer from Autodesk. Altium Ltd., the Australian company whose flagship Altium Designer suite is used by PCB and electronic designers around the world, said that the Autodesk offer “significantly undervalues” Altium, despite the fact that it represents a 42% premium of the company’s share price at the end of last week. Altium’s rejection doesn’t close the door on ha deal with Autodesk, or any other comers who present a better offer, which means that whatever happens, changes are likely in the EDA world soon.

There were reports this week of a massive explosion and fire at a Chinese polysilicon plant — sort of. A number of cell phone videos have popped up on YouTube and elsewhere that purport to show the dramatic events unfolding at a plant in Xinjiang province, with one trade publication for the photovoltaic industry reporting that it happened at the Hoshine Silicon “997 siloxane” packing facility. They further reported that the fire was brought under control after about ten hours of effort by firefighters, and that the cause is under investigation. The odd thing is that we can’t find a single mention of the incident in any of the mainstream media outlets, even five full days after it purportedly happened. We’d have figured the media would have been all over this, and linking it to the ongoing semiconductor shortage, perhaps erroneously since the damage appears to be limited to organic silicone production as opposed to metallic silicon. But the company does supply something like 17% of the world’s supply of silicon metal, so anything that could potentially disrupt that should be pretty big news.

It’s always fun to see “one of our own” take a project from idea to product, and we like to celebrate such successes when they come along. And so it was great to see the battery-free bicycle tire pressure sensor that Hackaday.io user CaptMcAllister has been working on make it to the crowdfunding stage. The sensor is dubbed the PSIcle, and it attaches directly to the valve stem on a bike tire. The 5-gram sensor has an NFC chip, a MEMS pressure sensor, and a loop antenna. The neat thing about this is the injection molding process, which basically pots the electronics in EDPM while leaving a cavity for the air to reach the sensor. The whole thing is powered by the NFC radio in a smartphone, so you just hold your phone up to the sensor to get a reading. Check out the Kickstarter for more details, and congratulations to CaptMcAllister!

We’re saddened to learn of the passing of Dale Heatherington last week. While the name might not ring a bell, the name of his business partner Dennis Hayes probably does, as together they founded Hayes Microcomputer Products, makers of the world’s first modems specifically for the personal computer market. Dale was the technical guru of the partnership, and it’s said that he’s the one who came up with the famous “AT-command set”. Heatherington only stayed with Hayes for seven years or so before taking his a $20 million share of the company and retiring, which of course meant more time and resources to devote to tinkering with everything from ham radio to battle bots. ATH0, Dale.