Cap Touch Morse Key

Hams like myself are always looking to play with technology, especially as it applies to our hobby of amateur radio. Whether it’s the newest, top of the line transceiver or a DIY dummy load, we’re interested – and this Capacitive Touch CW Key is a neat design! With a small touch-sensitive circuit powered by a battery, it can control any standard CW transceiver. From the look of the design, it can be used both as a straight key or as a paddle, which is a nice feature.

Why use something like this in the first place? Well, traditional keys are mechanical, and require maintenance and adjustment – not to mention they are a bit noisy! This design is completely silent (except for the sound of your dits and dahs) and will last for a long time. The only maintenance it might need is the very occasional cleaning of the touch pads, though even that is pretty unlikely unless they get particularly dirty.

The only downside is that it does require a CR2032. I would imagine that battery life is pretty good, and you can of course remove the battery when not in use, but a mechanical key doesn’t need any power at all, and so each have their pros. This is the sort of key that would be very useful on field day, or when in a quiet room with others – the silence could be a big plus! Just make sure you don’t call it a silent key or you’ll get some strange looks. 73 and good DX!

source https://blog.tindie.com/2025/08/cap-touch-morse-key/

Home Automation Controller

There are many good reasons to avoid commercially made home automation systems and roll your own. First of all, you take back control of your data, and can choose where and when to store it or delete it. For many, that’s reason enough; but you also get benefits such as being able to combine sensors from multiple vendors, create custom web UIs for viewing data and creating schedules and actions, and easy integration with open source software like Home Assistant. The Home Automation Mate from Elecram is an all-in-one home automation “hub”, ready for integration into an existing system or to serve as the base in an entirely new one!

Featuring the venerable ESP32-S3 Wifi/BT microcontroller, it supports a wide array of sensors out of the box, including CO₂ sensors (SCD40/41, MH-Z19), particulate matter sensors (PMS5003), and the Bosch BME280/BME680. Additionally, you can add any compatible Stemma QT/Qwiic compatible sensors or breakouts for additional functionality. A built-in colour OLED header makes it easy to show system status at a glance on a compatible display.

For powering everything, the board supports USB-C Power Delivery up to 9V, or 12-24V in through a standard barrel jack. An onboard regulator gives 5V/2A and 3.3V/0.5A for circuitry, plus a regulated output adjustable from 0.2-12V using PWM from the microcontroller. The same connector can also be used to power fans, either for drawing in air to sample or to cool power-hungry components like motor drivers.

If you’re willing to roll up your sleeves and dive into some coding, this platform is an excellent way to get started on a custom home automation setup. The creator has some example code repositories available for viewing and modifying: an air purifier project, and a plant monitoring project.

source https://blog.tindie.com/2025/08/home-automation-controller/

BT Internet Radio Player

Internet radio is awesome. Free, high-quality music, talk, news and just about anything you could want to listen to can be streamed from a huge number of servers worldwide. From national broadcasters like the BBC to independent, volunteer-run stations like Anonradio, there’s so much to discover. This cleanly designed, ESP32-based Bluetooth Internet Radio streamer is a great way to listen to your favourites on any Bluetooth audio devices you have!

With room for up to 1000 stations, the variety you can pack into this tiny device is amazing. Perfect for those who like having some background music or who like to listen to news from different countries. It needs an 18650 battery, but has built-in charging and can operate from USB-C without the battery if desired. 18650s pack a lot of energy and so the battery life should be excellent.

There are lots of websites that collate streaming radio URLs and make them easy to find by genre and bitrate. Many stations stream in 320kbps MP3 which sounds excellent! If you’re into internet radio or know of someone who would love this device, be sure to check out the video below to see how it works!

source https://blog.tindie.com/2025/08/bt-internet-radio-player/

All-In-One Environmental Sensor

Air quality monitoring has increasingly become front and center since the COVID pandemic. Once the populace learned about CO2 levels and how they’re a good proxy for air freshness, sensors have become increasingly popular. This nifty little board called the Canopy features the popular ENS160 CO2/VOC sensor in combination with the powerful BME280 for humidity, temperature and air pressure. Together, you get a very good picture of the air quality and environment in a particular area.

The Canopy is designed to work with related boards from Sprig Labs, together called SprigStack. This includes an ESP-C3 development board, plus other sensor boards for plant monitoring and motor control. Together, you get a very easy to use sensor platform that is designed to work with systems like Home Assistant for data collection and display.

If you want a quick and easy way to get some accurate air quality data, the Canopy looks like a great choice. You can also get the Sprig-C3 development board paired with it at a discount, so you can be up and running in no time. And with the Sprig-C3 attached, you can add a battery as it has built-in charge control!

source https://blog.tindie.com/2025/08/all-in-one-environmental-sensor/

A New Approach to Protoboard

Protoboard is a great way to try out circuits before deciding to get PCBs made, or as a way to quickly produce a project that’s on a deadline. Classic protoboard is just a big matrix of holes without any connections – you have to make all the connections between nodes with wires, which can get messy really quickly and make debugging a pain. The Protomatrix routable perma-breadboard can connect all 160 rows into 30 different nets, simply by bridging pads at the edge of the board.

Each column on either side of the board is commoned together. Then each row of the tiny pads are not only commoned, but also attached the same row on the opposite side of the breadboard! This way, you can quickly and neatly route signals around the board without using any wires. Not only does this result in a much neater-looking end product, it can also make debugging much easier, as it’s visually apparent which nodes are connected together. You can also easily disconnect nets by using solder braid to remove the solder bridges connecting rows and columns.

Of course, this design is more expensive than regular protoboard, but these are great to have on hand in case you need to quickly prototype something. Having the connections be soldered also increases durability, and the neat look makes user-exposed circuits more appealing.

source https://blog.tindie.com/2025/08/a-new-approach-to-protoboard/

Play with the ESP32-C5 – finally!

Espressif recently announced, after a very lengthy delay, that their RISC-V based ESP32-C5 chip is being mass-produced. This chip combines dual-band WiFi 6, Bluetooth 5 LE, and 802.15.4 connectivity for protocols like Zigbee and Thread. It’s similar to the existing ESP32-C6, except it has a faster CPU clock, supports dual-band WiFi, and has a bit more SRAM. It’s low-power co-processor (which many forget exists on the RISC-V ESP32 chips) also runs at double the clock speed compared to the C6. This little development board is a great way to get up and running quickly with the new chip!

With dual USB-C connectors (one for UART and programming, the other connected directly to the C5’s USB pins), on-board RGB LED, and even a current measurement test jumper, it packs quite a bit into a small package. However, because the official ESP-IDF libraries only added support for the C5 a couple of months ago, there isn’t (yet) an Arduino bootloader or Micro/CircuitPython runtime. These will likely be coming along very soon, but as of this writing using ESP-IDF is the only way to get up and running.

There is a lot of excellent documentation for using ESP-IDF, and there are already a multitude of video and text tutorials for getting started with the ESP32-C5. That being said, if you’re not a strong C programmer, you might want to wait for the Arduino or Python firmware to become available! Keep an eye out as more projects pop up using this chip – I think we’ll start to see some pretty cool things being done with a chip this small an inexpensive that supports true dual-band WiFi 6!

 

source https://blog.tindie.com/2025/08/play-with-the-esp32-c5-finally/

Transparent LCD for Optics

Technically, all LCDs are transparent; whether we can see them in certain light depends entirely on the backlighting or other reflective/transflective layers behind the LCD itself. However, it’s difficult to find bare LCDs like this, and you can do some neat optical tricks with them. This 0.8″ Transparent LCD Module features a resolution of 48×64, which might not seem like a lot, but with such a small display it’s a good compromise on price and performance.

These could potentially be used for AR applications, but I think using them with some lenses and LEDs to create small projection systems could be very neat. You could create some very interesting lighting effects with an array of these, plus lenses and RGB LEDs. Imagine lighting a transitional space like a hallway. The light could be constantly morphing, not only in colour but in shape and brightness as well!

Interfacing to the LCD is quite simple. It uses SPI for communication and any microcontroller should have no trouble sending commands and data. It’s based around the ST7565 LCD controller, and there are a lot of open-source libraries and documentation available to work with, so getting started should be a breeze.

Your imagination will come up with unique ideas too, and if you build something with this module, make sure to let us know about it!

source https://blog.tindie.com/2025/07/transparent-lcd-for-optics/

Bongo Cat! In Your Hand!

Maybe it’s the oppressive Toronto heat getting to me, or maybe I’m just too silly for my own good, but when I saw this Bongo Cat Fidget Toy come up I couldn’t stop laughing. First of all, Bongo Cat is cute. And we all want to make Bongo Cat… bongo. So the beauty and simplicity of this fidget toy is seeing how fast you can bongo with Bongo Cat!

With a common SSD1306 OLED, an STM32G030, two mechanical keyboard switches, a battery and a boost regulator, the hardware is simple and easy to build. You can keep track of how many times you bongo, as well as bongos per second. These stats can be reset, if you get ashamed of how much bongo you’ve bongo’d.

This is actually a great example of how to put together a small project like this. The entire thing is open source, and the hardware and software are available on GitHub. You can edit the KiCAD files and the source code to see how it was created, and even tweak it or use the 3D model to create a 3D printed case! Just remember to have fun.

 

source https://blog.tindie.com/2025/07/bongo-cat-in-your-hand/

Share Your Commodore Peripherals

If, like me, you have a collection of Commodore computers and IEC bus devices (disk drives, Pi1541, printers, etc.), it can get annoying to have to constantly switch cables around depending on which accessory you want to use with a particular computer at a particular time. I only have a single 1541 disk drive, but I use it with both my C64 and my VIC-20 often. Additionally, I have a Pi1541 which acts like another disk drive, and it is always in high demand. This IEC Bus Switching Box can make things much simpler. Leave all your devices hooked up, and just switch which bus they are connected to!

The simplicity of this switching box is also its power. It simply has two IEC busses internally – A and B. Pressing a switch in connects it to one bus, and popping it out connects it to the other. It’s intended to be used with two computers; one connected to position 1 which is always left popped out, and another connected to position 2 which is always pressed in. Then, individual devices (or daisy chains) are connected to 3, 4 and 5. Whenever you want to connect them to a particular machine, just change the state of the switch. This will connect that device or chain to whichever internal bus you like, and thus to which computer you want to use it with.

This approach is easy to use and very simple, which makes it robust and fairly foolproof. The boxes come in a variety of colour schemes — I definitely like the shown Blue Sky theme, but the black and grey Midnight theme is also very nice and fits with any era of computer. So if you’ve got a lot of IEC devices and want to stop the cable shuffling game, check this switching box out!

source https://blog.tindie.com/2025/07/share-your-commodore-peripherals/

ADS1115 ADC in Qwiic/Stemma QT Form

Following on from yesterday’s constant current driver, today we have another I2C-controlled device on a nicely sized, easy to use breakout board. This Qwiic/Stemma QT Compatible ADS1115 16-bit ADC board makes it easy to get high-resolution analog measurements to your microcontroller. The ADS1115 is not just a low-power, high-resolution ADC – it also has a built-in programmable gain amplifier and a digital comparator. However, these are not high-speed ADCs – the typical maximum sample speed is 860 samples per second.

Even though the sample rate is low, the accuracy and drift specs are great. Integral nonlinearity and offset error are typically under 3-4 LSBs, with long-term offset drift of just ±1 LSB after 1000 hours at 125°C. If you want to do long-term, low-drift accurate measurements, it’s hard to beat a low-power ADC like this. And it does all this while using 150μA operating, and just 500nA in sleep mode, making it ideal for remote, battery-powered devices.

This PCB has nice, big solder pads for the 4 inputs (which can be used as 2 differential inputs if desired). You can easily change the I2C address to get more than one on the same bus. And with lots of documentation and example code out there, you can get up and running quickly! Just grab a board that has a Qwiic/Stemma QT connector, attach this breakout, and you’ll be getting accurate, high-resolution measurements in minutes.

 

source https://blog.tindie.com/2025/07/ads1115-adc-in-qwiic-stemma-qt-form/

Qwiic/Stemma QT Constant Current Driver

In basic projects, controlling LEDs and other current-driven devices with a PWM signal can work fine. However, there are disadvantages, and using a constant current source can be a much better solution. This Qwiic/Stemma QT compatible Current Controller uses a large MOSFET and a DAC in a feedback loop to provide a constant current flowing between the two  screw terminals.

If you’re new to electronics, constant current sources can sometimes be tricky to understand. Unlike a constant voltage source (which we’re used to with things like power supplies, batteries and the like) which put out a variable current at a fixed voltage, constant current sources do the opposite. They will dynamically adjust the voltage across a device to ensure a certain current flows. Of course, they also have a voltage limit (just like constant voltage devices have a current limit) meaning they can’t just infinitely push current through any impedance. But for devices that are current-driven like diodes of all kinds, constant current sources give you a fine level of control. They can eliminate the need for series resistors, too, which can reduce the heat generated. Just remember, it all obeys Ohm’s law!

Laser diodes in particular are better driven with a constant current source, as you can compensate for varying light output by adjusting the current through the device. This current source is adjustable in steps of 1mA, all the way up to 950mA. The circuit supports a maximum of 30V, so you can power quite a string of LEDs or lasers.

 

source https://blog.tindie.com/2025/07/qwiic-stemma-qt-constant-current-driver/

Compact ESP32-C6 USB Dev Board

The ESP32-C6 is the latest version of the RISC-V based ESP32 wireless microcontrollers. Like all the ESP chips, it supports WiFi and Bluetooth (in this case, WiFi 6 and BT 5), but the C6 packs an extra punch — support for 802.15.4-based protocols, like Thread, Matter, and Zigbee. These use the same 2.4GHz ISM band, but use totally different protocols to facilitate low-power, short-range mesh networks. This compact USB-based ESP32-C6 dev board makes it easy to get up and running quickly, but also has castellated pads to integrate it into a long-term project if needed!

With a built-in power regulator, direct USB connection and small form factor, it’s a great way to get familiar with the ESP32-C6. I2C, UART, and a selection of GPIO are broken out to castellated pads, but the focus of the design is on compactness and ease of use — it’s as easy to plug in to a laptop as it is a Raspberry Pi without taking up too much room. Programming is easily done over USB with esptool, and ESP-IDF has full support for this chip.

Another nice feature of the C6 is the ultra-low power co-processor – a much smaller RISC-V core that has access to a subset of peripherals and can remain running while the main processor and/or radio subsystem sleeps, giving huge power savings without sacrificing low latency response to external events or timers. If you’ve ever wanted to play with 802.15.4-based protocols, or just want to toy with the latest and greatest ESP32, this USB dongle is a perfect place to start!

source https://blog.tindie.com/2025/07/compact-esp32-c6-usb-dev-board/

Minty Retro Gaming

So many great projects have been inspired by the challenge of fitting a project into a classic Altoids tin. From the Adafruit MENTA, to the original Atari Punk Console, the Altoids tin just seems like the right size for a handheld gadget. This time around, a Raspberry Pi Zero W 2 is packed in along with a Li-Po battery pack, custom controller PCB and LCD screen to make the RetroPie project fully handheld and portable.

The kit comes with almost everything — you will need to 3D print some parts yourself. The included controller buttons use the same tactile switches and membranes as the Game Boy Advance SP / DSi for a premium feel. The 2.8″ 320×240 display is about the largest you can possibly fit comfortably in the lid, and the RetroPie project is capable of emulating SNES, PS1, Genesis/MegaDrive, Game Boy Advance, and much more!

There is a slightly easier to build version which only uses 3D printed parts — the Altoids version is considered trickier to build correctly, and the space is restrained necessitating a 40% smaller battery. However, the 3D print files are available to convert one into the other if you don’t like the look or feel of the Altoids tin version.

source https://blog.tindie.com/2025/07/minty-retro-gaming/

Ultimate Upgrade for the Amstrad CPC

If you own any of the machines in the Amstrad CPC series – from the CPC464 all the way up to the CPC6128 – then you know it can be difficult to find and maintain the unique Hitachi-based 3″ discs that Amstrad used for program and data storage. Not only that, but getting cassettes and ROM expansions can also be costly and time-consuming. Well, the ULIfAC Multi-Function Board for the Amstrad CPC contains literally everything you need to fully expand and enjoy your CPC computer!

You can choose between varying combinations of 512KB RAM expansion or 32 ROMs – for example, you could have 256kB of RAM expansion with 16 ROM images at once! Loading speeds are 6 to 7 times faster than through the floppy drive. You can load disc images and ROMs directly from a USB storage drive, and also have up to 4 discs loaded simultaneously. The board also supports automatic ROM mounting on cold boot, so you can have OS expansions or other utilities installed right from the moment you turn the machine on.

It adds many new commands to the BASIC interface to simplify file management and configuration. Also, it fully supports running with CP/M Plus (aka CPM/ 3), which is a neat feature on the CPC that not many took advantage of. Well now you can easily load and enjoy supported CP/M software and also easily write your own. With the expanded RAM, large programs can be easily loaded and edited.

If you’re an Amstrad enthusiast, then you’ve gotta take a look at this board!

source https://blog.tindie.com/2025/07/ultimate-upgrade-for-the-amstrad-cpc/

DRAM Tester for Vintage Computers

One of the most common issues with vintage computers is faulty RAM. For whatever reason, certain manufacturers and part numbers seem to fail at a much higher rate than others. Being able to test suspect RAM can be hugely helpful. This DRAM Tester supports a wide range of common parts – the 4116, 4164, 41256, 4332, 4132 and many more.

Sometimes the parts fail completely and it’s obvious that they are damaged. But in many cases, you’ll have intermittent faults or strange behaviour that comes and goes. Some software diagnostic cartridges can do RAM checks but if you regularly repair or test vintage computers, having a hardware RAM tester on hand can make the job a lot easier — especially if you’re unable to get software to load due to RAM issues.

With four different test modes, you can find out if there are faulty cells, issues with dynamic refresh, or intermittent faults. It can also be handy to test purchased RAM chips before installing them to make sure you’re not installing faulty parts! If you deal with any of these older dynamic RAM chips this tester will make a great addition to your toolkit.

source https://blog.tindie.com/2025/06/dram-tester-for-vintage-computers/

Educational Circuit Books

These educational books aren’t “books” in the traditional sense. They’re books made of circuit boards, with each “page” covering a useful reference circuit. The first two volumes cover DC Circuit Fundamentals and LEDs, Transistors and Oscillators. The pages are fully functional circuits with descriptions, and include fundamentals like Kirchhoff’s Current and Voltage Law, RC time constants and more.

This is a really neat way to learn about electronics fundamentals with circuits that are guaranteed to work; all you need is a USB-C power supply and a multimeter and/or oscilloscope to probe the circuits. These could be a great accessory to have around a hackerspace, or even in the science classroom! Hang them on the wall near the soldering station or design computers as a handy reference, or use them when teaching small gatherings of students who are discovering electronics for the first time.

The existing volumes are gorgeous gold and white on matte black, which gives them a premium look and feel. We’re looking forward to seeing more volumes released, hopefully covering increasingly advanced circuits!

source https://blog.tindie.com/2025/06/educational-circuit-books/

VIC-20 Video Mod

We are huge fans of retro computers here at Tindie, and the constant stream of amazing new tweaks and hacks for these classic machines never ceases to amaze us. This S-Video and Composite Mod … Thing for the VIC-20 improves the output quality of the composite video and adds an ultra-sharp S-Video output to boot! While the VIC-20 was a solid design, most televisions in the early 1980s simply didn’t have the ability to resolve fine edges and so the original VIC chip didn’t need to generate top-tier video output, it just had to be good enough to be usable.

As time wore on and TV technology vastly improved, the shortcomings of the original composite output stage from the VIC became more and more obvious. Fuzzy output, ringing on high frequencies leading to loss of definition, and poor contrast all added up to make the picture less than stellar. On a modern television, the VIC-20 looks… pretty sad, to be honest. But this board remedies that by retroactively applying high-quality circuit design and quality components to the output stage. The difference really is astounding:

Installation requires some soldering, but nothing too difficult. If in doubt, just wrangle the nearest hacker by offering cake and cookies in exchange for soldering. It’s possible to install the mod in such a way that it can be completely undone in case you want to return your VIC back to its original form, though we suspect few will want to!

source https://blog.tindie.com/2025/06/vic-20-video-mod/

ESP32 AI On The Edge Module

If you’re looking to build a wireless device with AI features to take advantage of the so-called AI On The Edge, you need reliable power, good wireless connectivity, and enough horsepower to do some or most of the processing on-device. This AI-On-The-Edge-Cam device is designed to specifically work with a particular software framework. The project initially used the generic ESP32-CAM devices, but they lacked hardware features that are required for typical applications, like battery and power management, Ethernet/PoE and camera backlighting.

Unlike typical applications, which might gather video data on a remote device and then submit those images to a powerful cloud server for processing and analysis, AI On The Edge moves some or all of that processing to the device itself, speeding up reaction times and allowing easy scalability. This kit comes with an OV2640 camera module, which can sample at up to 1630 x 1230 @ 15fps, or up to 60fps with CIF resolution.

USB-C allows for easy charging and programming, and an onboard Stemma QT connector adds easy I2C expansion. PoE support allows for permanent installation, but battery-powered applications are also possible. 4 RGB LEDs allow for camera backlight compensation. All in all, it’s a powerful little package with many possible applications!

source https://blog.tindie.com/2025/06/esp32-ai-on-the-edge-module/

Teensy 4.1-based Programmable Guitar Pedal

The Teensy 4.1 is famously powerful, with a 600MHz ARM Cortex-M7, a 64-bit floating point unit, gobs of flash and RAM (which are expandable!) and certain interfaces that are ideal for audio processing, like I2S and S/PDIF. This Programmable Guitar Pedal combines the intense processing power of the Teensy with a high-quality ADC and DAC audio chipset, the WM8960, to create the ultimate in customizable guitar effects pedals.

The Teensy Audio Library is a very well-written and easy-to-use audio processing library which is perfect for applications like this. The documentation includes a few examples of simple effects like Bitcrusher and Delay, and it’s amazing that each effect is only a hundred or so lines of code. There is even a GUI application to help you design and tweak the audio processing, so you can quite literally create just about any sound you can imagine. The possibilities are truly endless!

If you’re a guitar player and are willing to learn a bit about how the Teensy Audio Library works, this could become a key part of your pedal lineup. It’s designed to fit into a Hammond 1590B enclosure, a very popular enclosure for guitar pedals, so you can decorate it and make it uniquely your pedal. Check out the full listing page for all the details!

source https://blog.tindie.com/2025/05/teensy-4-1-based-programmable-guitar-pedal/

Apple ][ Digital Video Output

It’s truly amazing how much power hackers have been able to squeeze out of the dual-core RP2040. Considering they are only Cortex-M0+ cores and not the more powerful M4 or M7 cores, generating signals like DVI and HDMI is simply amazing. This add-in card for the classic Apple ][ adds a digital video output which is significantly sharper and, of course, easier to use with modern displays and TVs.

It generates the video signal directly from the video RAM contents, and because it has total control, it can easily do 80-column output, alternative character sets and keyboard layouts. Because the communication is bidirectional, future expansion for the card could easily add features that modify RAM contents or snoop on the expansion bus. Already, a special firmware for the Apple 2e allows it to emulate a floppy drive!

Like a Pico, it has a USB-C connector for power and programming when not being used in the machine. Otherwise, it gets power from the Apple ][ and runs completely self-contained. The display emulates the classic Apple artifact colour look, though I’m sure it would be possible to convert the artifact colours into true, regular colour outputs — I wonder how that would look? If you’ve got an Apple ][ and don’t want to keep a classic CRT around for it, this is a great option to bring it into the 21st century.

source https://blog.tindie.com/2025/05/apple-digital-video-output/