Tindie

As you go about your day-to-day life, you probably have some vague understanding that there is air pollution around you. However, actually putting a number on how air quality changes from one day, week, month, or even year to the next isn’t something you can sense, much less track, without assistance. To help make sense of instantaneous air pollution and overall trends, AiryFi provides a way to display stats locally, and also beam them out via WiFi.

AiryFi uses a PMSA003 sensor to get data on suspended air particles in the PM1.0, PM2.5, and PM10 ranges (signifying the respective maximum particle diameters measured in micrometers), and displays this via an onboard 1.14” TFT screen. A BME280 sensor is also implemented, providing temperature, pressure, and humidity readings. The design is open source, with documentation found on GitHub.

Processing for the device is via an ESP8266-12E module, which also provides communication via 2.4 GHz WiFi. This gives it the ability to transfer information to your Android or iOS device, and also to work with ThingSpeak, allowing for near-limitless tracking and data analysis over time. Ideas that come to mind include correlating pollution with humidity and/or the season. You could also simply take a stroll with one of these units in-hand as shown in the video below, observing how things change from one location to the next.

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It wasn’t long after the advent of addressable RGB LEDs that LED rings began to appear. Even though they are commonplace, we still think that these circles of glowing wonder are a spectacle to behold. They are usually pretty big, often starting at around 36mm in diameter and increasing upwards in size, limited perhaps only to what you can afford!  MakeTVee has gone the other way and has come up with this excellent set of LED PCB rings that are only 18mm in diameter.

Sold as a pack of 4, these little rings each have 8 WS2812C addressable LEDs mounted onto a 1mm thick PCB. Due to the small package size of the LEDs, the internal diameter of the ring is 10mm. On the back of each ring, there are solder pads for a 5V supply and ground as well as data in and out which means you can easily chain together multiple rings.

There’s a tantalising mention in the description that you could use these rings to build “Tiny LED balloons”. We weren’t familiar with this project but Maketvee included a link to @ItsMrHJP on Twitter who is building these beautiful model balloons using LEDs and edge-emitting optical fibres. We’d also bet that people have more technical uses for these; a first thought here was that they might make excellent light rings for tiny FPV-type camera systems. Whatever you choose, we look forward to seeing what the Tindie community uses these for!

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There are lots of floppy drive emulators floating around for sale these days. However, most of them have a very simple interface that can be frustrating to use. Enter the GoFloppy external floppy drive: not only does it have style, it also features an OLED display that shows you exactly which image is in use. This is a much better user interface than most of the floppy emulators available.

Unlike most emulators which use USB flash drives, this one uses SD cards, which may be a better choice depending on what you have available. Often, SD cards have higher read/write speeds, especially when compared with USB 1.1 or even USB 2.0, which most emulators use. This emulator uses the FlashFloppy firmware, which means it’s compatible with pretty much any retro computer that used 3.5″ floppy drives with 34-pin cables, including the IBM PC line, the Atari ST, Commodore Amiga, Acorn Archimedes, and many more.

This particular design also has a switch to easily change the floppy ID, so it can appear as a primary or secondary drive without having to change jumper settings or move it to a different spot on the floppy cable. The OLED display also shows which track and sector are being accessed; this can be really useful when using old floppy images that may have problems, or if you are trying to use copy-protected software that looks for “bad” sectors in particular spots.

Check out the video below for a demonstration, and consider grabbing this or one of the many other products Retro Supplies offers for retro computers!

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I have many component drawers full of breakout boards for various different development boards: Arduinos, Picos, and microcontroller dev boards of all shapes and sizes. It can be frustrating when I want to quickly prototype a circuit idea and I have to go rummaging around trying to find the right breakout. Well, this Universal Breakout Board design makes quick work of breaking out DIP-style development boards of just about any length or width.

Simply plug in whatever DIP package development board (or even bare chip!) and get a 0.1″ female pin header with all the pins broken out. This is particularly useful when trying to use development boards like the NodeMCU, which would hardly fit on a standard breadboard.

The Standard design brings out half of the pins to each side of the board, where both a male and female header can be soldered to attach jumper cables or wire. The Pro design brings all the pins out to each side, meaning you can keep all the cables confined to one side, or even solder in a male header and plug the breakout into a PCB if needed.

Having a few of these in your lab could replace unique breakouts for many different devices! Reduce some clutter and make your next prototype look a bit neater. Turkish designer Mete Hoca also sells pinout stickers for ATmega328P and Arduinos, as well as some other neat tools!

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I love retro-style microprocessor trainer boards. These were common back when microprocessors were still relatively new, and trainer boards were a good way to learn how to use them. Essentially, they were single-board computers, but they were often kits that had to be assembled (good soldering practice!) and they often had features specific to their mission of teaching, rather than trying to be general-purpose single-board computers. The PLC14500-Nano 1-bit Single Board Computer Kit is taking that same idea of a microcontroller trainer board and applying it to the unique Motorola MC14500 1-bit CMOS processor.

“How can a 1-bit computer be useful?”, you may be thinking. Well, while it technically is Turing-complete, that wasn’t the intended purpose behind these chips. They were designed to replace relay logic and other electromechanical control systems where the functions are relatively simple. Because so much of the design depends on the choice of external chips (it doesn’t even contain a program counter — this is contained in an external chip!) it was an extremely flexible and cost-effective design that was briefly very popular before microcontrollers came along and took over.

So what can you do with this kit? Well, first of all, just like trainer boards from the 1970s, you have to solder it together yourself. This is a great opportunity to study the schematic and learn how the system is designed. Once it’s built, you have a whopping 256 bytes of RAM to write any programs you want! Well, any program that can fit in 256 bytes, anyway. It has 7 inputs and outputs that could be connected to just about anything (assuming you remove the buttons/LEDs that are there by default). It even has control of the clock, allowing you to single-step through your program, which is an important feature on a trainer board. This way, you can see the system working one step at a time. With an oscilloscope probe in hand, you can learn an awful lot about microprocessor internals.

Yes, there’s a sneaky modern intruder — an Arduino Nano is there simply to make development easier by providing a way to upload code to the board. The designer recommends soldering it to the back of the board so as not to ruin the illusion of a retro machine! This would make a great gift for anyone keen on learning about processor technology or any hacker who is interested in oddball, unique designs.

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Now and then — in any hacker’s lab — the need to measure large currents comes up. Most multimeters have a 10A range, which is okay, but it often has a significant burden voltage and accuracy isn’t great unless you have a fairly high-end meter. And 10A can be limiting — sometimes the need to measure 50A @ 0.7V comes up. Well, this beefy, heavy-duty 200A current shunt is a great addition to any lab.

With a 10A per V output, any decent multimeter can get precise current measurements. Power this shunt with 24V and you can easily measure right up to the 200A limit! Now that’s a lot of power current!

The bandwidth of the measured signal can be important, and this shunt has a bandwidth of about 7.5kHz — enough to do some low-frequency measurements, but mostly useful for large, power-hungry DC loads.

It was originally developed to help measure a huge DC power supply, and this could easily be integrated into a test/measure setup for testing high-output power supplies, such as common ATX PC power supplies. Many modern ATX supplies can easily output hundreds of amps on the 12V rail, and this shunt would be very useful in characterizing the output of these supplies under heavy loads.

So if you need a reliable, well-built DC current shunt for under $25, check it out! Repowered Electronics also have other products designed for working with heavy-duty DC power.

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If you’ve got a modern boiler or HVAC system that supports the industry-standard OpenTherm interface, there’s a lot you can do with it! This tiny board pairs with an ESP32-S2 mini and allows you to integrate your existing OpenTherm thermostat with various home automation control systems, like the ever-popular Home Assistant, Tasmota, OpenHAB, etc.

By adding Wi-Fi or Bluetooth connectivity, you can easily control the temperature in your house based on whatever inputs you desire. It would be easy to implement multiple temperature sensors around the house to see how effective the heating/cooling is in each room and adjust the entire system for an acceptable average. Or you could implement a basic zone heating/cooling system by adding an electromechanical system to open/close HVAC vents. Your only limit is your imagination!

This board is designed to be paired with the powerful ESP32-S2 and comes with the software to immediately connect to Home Assistant via MQTT. It will appear in your Home Assistant monitoring software, and if your HVAC/boiler system supports it, it will also report information about the status of the system: whether it’s running, whether the flame is present, flow information, as well as outlet and return temperatures for boilers. This can enable you to calculate the heating efficiency of your system to a very fine level, allowing you control over how much energy you use and how much of a CO2 footprint you produce.

Systems like these will become more and more common as energy efficiency becomes increasingly important as we work to fight climate change. You can get started today with this fully customizable system!

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I’ve been an amateur radio hobbyist for quite a few years now, and like many who have gotten started in the past decade, I started out with a Baofeng UV-5R as my VHF/UHF radio. Because these are so inexpensive and have an easy-to-use audio interface, you can do a lot of neat stuff with them, including APRS, digital communication (including sending/receiving email over the air!) and much more. In order to get this working, however, you need some way to interface a computer to your radio. Enter this great little CM108 to Baofeng adapter board!

The CM108 is an easy-to-find USB soundcard that works with just about any computer and OS out there, including Raspberry Pis and other single-board computers. It’s plug-and-play — you plug it in, and new audio devices show up. If you connect one of these to this adapter board, you get an interface that plugs directly into the radio. All you need is an extra headset cable — and they are a dime a dozen online. This prevents you from having to connect directly to the radio and also takes care of triggering the Push-To-Talk or PTT using a MOSFET.

If you’ve wanted to get into digital modes with your VHF/UHF station, this is a great way to get started. Pick up one of these boards, a CM108, and a spare headset cable (or just chop up the one that comes with the radio — that’s what I did originally!) and you’re ready to go. You can use software like FLdigi, Xastir, and Winlink Express to experiment with all sorts of neat digital modes!

And if you’re not an amateur radio license holder yet — what’s stopping you? The requirements vary by country, but a week spent studying and typically a small fee will get you on the air! There’s lots of cool hacking going on in the amateur radio space, so don’t miss out!

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If you’ve ever lived through a cicada summer, you are familiar with the deep penetration their cries will inflict on your brain. For the blissfully unaware, this sound will follow you throughout your day and into the dusk hours, the drone eventually integrating into the white noise of your mind. But there’s something fascinating about the sound cicadas produce for me, especially having lived in the southern United States most of my life. I’ve got through summers where the cicadas were so prolific, I had to sweep them off of my windshield before driving to work each morning. So when I saw the Cicada 2.0 Solar Sounder, a PCB for reproducing the sound with a digital twist, I was intrigued, to say the least.

This is an unpopulated PCB with some gorgeous masking artwork and enough components labels to feel like an achievable DIY, you have the chance to make your own cicada calls with this project. If you’ve got a drawer full of spare components you’re looking to clear out, this project is an excellent opportunity to do so, as you’re encouraged to try different values to play with the signal. And an element that rings so creative and thematic is the inclusion of a solar panel as the power source. The fluctuation of light over the day will change the signal, much like how the pitch and volume of the cicadas change as the day goes on. For extra flair, try sticking the panel under some meandering shadows cast by a nearby tree, and see what sound a partially obscured solar panel makes.

If you already yearn for the summer months and what sounds that may bring, pick up this project and bring those summer months to you. It’s made by Graham’s Gear Bazaar, based in the United States. They also provide a detailed BoM with the package, if you’re looking for a bit more guidance in your cicada signal project build!

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One of the few complaints one could have about the Pixhawk drone flight controller is an issue with running extended-length I2C cables. Not only does making a cable extension usually involve some pretty finicky cable making, but most drone components come with JST connectors as well for structural integrity. And even if you were to build that longer cable, the EMF signature that drone motors produce is more likely to interfere with your signal integrity. To answer that problem, the TFI2CEXT module is here to give you an easy fix to a complicated scenario.

One of the greatest benefits of this board is its ease of hookup, with a JST-GH connector on both ends, compatible with the PixHawk connection standard. It also features power and
“ready” status LED indicators, plus the extender can perform a device reset if any issues arise midflight. Additionally, the routing on this board is done in such a way as to easily allow nesting of other I2C devices if you’ve already got pre-existing cabling onboard. All other documentation, including the PCB layout and exact dimensions of the board, are also available on the product’s Github page!

This I2C module is brought to us by ThunderFly, the Czechia-based drone supplier. They have a number of other drone accessories as well, including this Air Speed Sensor and this IR and Magentic Probe, in case you’d like to pick up some sensors to connect to your brand new I2C extender! Check out their page and see all the wonderful drone-based goodies they offer.

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