Tindie

I sometimes think stepper motors are the heart of the hardware maker movement. They occupy many positions in robots and other mechanical assemblies that we build. This Mini Stepper Linear Sliding Actuator definitely has the potential to sit inside some interesting builds.

It’s a tiny stepper motor mounted on a bespoke PCB. The output shaft of the tiny stepper motor takes the form of a threaded lead screw. The threaded lead screw has a small carriage on it which, when the stepper is driven, can travel up and down the small length of the threaded lead screw. Hanging off the side of the carriage is a small hook, meaning it’s pretty trivial to attach this to all kinds of systems. Linear actuators can be very useful any time linear movement is required. They’re a simple way to turn rotational motion from a motor into linear motion along a track or lead screw. Just remember that this conversion loses some of the torque from the motor!

To drive the stepper motor it is mounted onto a custom PCB which has a DRV8833 motor driver IC onboard. These are a common and excellent little motor driver and as such you’ll be able to find examples and libraries across many different platforms. Arduino, ESP32/8266, and Raspberry Pi Pico CircuitPython would all be fair game to drive this little actuator. For precision movement, you could add feedback using a limit switch or optical sensor.

So what will you build? The product page suggests projects like robot arms and crane assemblies. I think that you could probably make a very nice robotic hand using these!

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The SC131 is a very neat looking and compact retro computing platform built around the Z180 CPU. The Z180 is clocked at 18.432 MHz and there’s a healthy 512k bytes of RAM and 512k bytes of flash memory on board. Pre-installed to the flash is the RomWBW firmware which is described as a robust implementation of CP/M.  You can read more about RomWBW over on the RomWBW repository here.

There are lots of options over on the product page, from PCB only through to a complete kit with the needed USB serial adaptor and USB cable. With the complete kit all you would need to add is a micro SD card for some on-board storage. It’s probably fair to say this isn’t a soldering kit for an absolute beginner. There are a few tricky sections in the assembly that might be a challenge for those who haven’t assembled a few kits and projects before. It’s definitely worth reading through the excellent and detailed assembly instructions in this guide to give you a sense of what you are up against in this build.

With the built in FTDI USB to serial adaptor you’ll need, like with many retro computing platforms, to hook this up to a computer with a terminal emulator installed. Once up and running we can imagine this neat unit providing plenty of retro entertainment!

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Effects pedals have long been a popular DIY/kit-build for guitarists looking for strange and unique sounds. Guitarists often reproduce pedal designs from many decades ago, reviving projects found in hobby magazines and expired patents. But the Inkcap II is something entirely different.

I’ve never heard a pedal quite like this. Emulating tape wow and flutter sounds really eerie and slightly other-worldly, especially once the chorus portion is enabled! The kit includes the PCB, a pre-programmed chip, and a vactrol, which was a name I had never heard before. Turns out it’s essentially an opto-isolated variable resistor. The resistance on the output side depends on the amount of current going through the LED side. They’re often called resistive opto-isolators.

While not all the parts are included, the remaining parts should be easily available and many guitar pedal enthusiasts likely have them in stock — stompbox switches, 1/4″ in and out, TL072, and a smattering of capacitors, resistors, LEDs and transistors. Definitely check out the video below to hear the spooky, weird sounds this pedal makes!

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CAN, or Controller Area Network, was originally developed as a resilient differential bus for controlling various systems inside automobiles. From the throttle to the spark timing, to the air/fuel mix, pretty much everything inside a car is controlled by the ECU (engine control unit), a small embedded computer that’s usually very proprietary and potted with resin. If you’ve ever wanted to log data for your automobile, or any other device using CAN (there are quite a few these days!) then the CANarchy is a great choice.

With a small OLED display and an ESP32 running the show, you have a lot of flexibility. The firmware is based on CircuitPython so modifying it for a particular use shouldn’t be difficult. One of the features that really stood out to me is the ability to take 12-72V input voltage! In North America, almost all vehicles use a 12V system, but in Europe and other places, it’s not uncommon to come across 24V trucks, and various other systems often use 48V (telecom, for example). Being able to run off of almost any available voltage is a really nice touch.

But how do you access the CANbus to begin with? Well, by law, automobiles made since 1996 in the US and since 2001 in the EU must have an ODB-II port, which allows you to connect directly to the main CAN bus inside the vehicle. This is how those diagnostic dongles can tell exactly what’s going on. But those dongles rarely let you send commands or log data, whereas the CANarchy can do both. You can send any arbitrary CAN message, log data to an SD card, or send pre-recorded data. Plus, with Wi-Fi on board, you can easily create a web portal to monitor and/or send packets in real time or send them to a logging system like Adafruit IO with MQTT.

Just a word of caution: only hack things you have permission to hack! Make sure you have the consent of a vehicle owner and don’t experiment with new commands on public roads. Test things out in an empty lot and see what you can do.

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If you’re into programming microcontrollers, you likely already know how useful debuggers can be. Not only can you execute your code step by step, but you can see the values of every variable, and view and change any part of memory arbitrarily. JTAG is standard on all ARM Cortex chips, and many other microcontrollers as well. However, some JTAG debuggers can be very expensive. This JTAG Hat turns any Pi 2/3/4 (and presumably 5) into a JTAG probe with a few common connector types.

By using software like OpenOCD and GDB (the GNU debugger), you can connect to the Pi from your laptop to remotely debug a connected board, or you can SSH into the Pi and debug directly from there. It can power the board from the Pi’s 3.3V supply and also has level-shifting buffers to connect to targets from 1.8-5V.

Additionally, it has an on-board measurement of the target voltage and current draw, which can be extremely useful when trying to optimize a project for low power draw. It can do just about anything any JTAG probe can: from programming flash, to watching the state of I/O pins, to resetting the processor remotely. If you want a great general-purpose JTAG debugger, and you have a spare Pi handy, this is a great way to get a cost-effective yet powerful debug probe!

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Often small electronics projects don’t need lots of power, they perhaps only need a tiny bit of power infrequently. It can often seem overkill to have a large battery permanently tethered to a project that you might only power on every now and again. We’ve even questioned ourselves about building a charge controller for some simple sensors that only needed an occasional manual check. This Hand Cranked Energy Harvesting Board could be a really useful and sustainable solution to these types of projects.

It combines what looks like one of the N20 style metal geared DC motors set up as a generator to feed into an onboard 7.5V 0.5F supercapacitor. Watching the video on the product page it appears to take around 25 to 30 turns of the small crank handle to fill the supercapacitor if it’s completely discharged. Once charged to 3.3V, the onboard LTC3588-1 IC enables the power output via the Vout pin. The output voltage on the Vout pin is switchable between  4 voltages: 1.8V, 2.5V, 3.3V and 3.6V. This is achieved by setting two pairs of jumper pins accordingly.

Finally, there are 2 M3 mount holes on the PCB which can be used to mount the device to a support structure. We can imagine building this into a nice small case with some kind of barrel connector output for a super portable pocket power supply!

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Reverb is a delay effect that can make instruments sound bigger and more bombastic. Before digital delay circuits, there were a few physical ways to create reverb. In a studio, plate reverb was common. This sent the analog signal across a huge metal plate, suspended by springs inside a box. Then a pickup would be somewhere else on the plate, giving a reverb sound. But plate reverb units are massive, so for live music, another variety was needed. This is the spring reverb — the sound is quite literally sent across a spring under tension! To properly use a spring reverb, you need a driver circuit, and that’s what Mad Hatter Electronics has developed.

Spring reverb units come in many shapes and sizes – some have one spring, and some have multiple. They can be made from different materials to get different tonal qualities. Many musicians like to experiment with random springs to see what kind of sounds they can get, and that’s where a circuit like this comes in. The analog input needs to be amplified and the spring needs to be driven pretty hard to get the sound through. After going through the spring, there’s another stage of amplification before being sent to the amplifier.

Spring reverb is popular across many genres of music, and because spring reverb units (often called “spring tanks”) are so small, they can be built directly into amplifiers. This unit is small enough that you could definitely modify an existing amplifier to add a custom spring reverb! All you need is a bipolar supply (quite common in amplifiers anyway), with +/-15V suggested. So bust out your guitar, soldering iron, and grab some springs and make some crazy sounds!

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Macropads have been all the rage for quite a while now. However, many people still haven’t discovered how awesome having a macropad can be! This Pico-based DIY Macropad Kit is inexpensive and easy to build. With a variety of macropad firmwares available for the Pico, you’ll have your choice of how to customize it.

While it doesn’t use mechanical keyboard keys like many macropads do, why spend the money if you’re not sure you’re going to find it useful? 6 keys is a good number to start with, enough to map your most commonly used keyboard shortcuts or macros and still quickly memorize which is which. If you discover that 6 buttons isn’t enough, you can always hack more buttons on, or move up to a bigger, meaner macropad with tons of RGB LEDs and the clickiest keys ever!

Even this starter kit has a few nice touches, like the LEDs underneath to give a glow surrounding the macropad. It even has a button for turning them on and off! The example code uses CircuitPython, but you could easily flash QMK or another popular macropad firmware if you want to really up your customization without writing a bunch of code.

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I love seeing projects where people take electronic components and make them bigger. Whether it’s a discrete version of an IC or a huge 7-segment display it just tickles me. The original purpose of this display was to create a radar speed sign Halloween costume, which is the sort of humour that I also greatly appreciate!

Built from individual segment boards, each section can be independently controlled and has an array of super-bright, daylight-readable amber LEDs. At 12V, each segment consumes about 120mA at full brightness, so the number 8 takes 840mA! Definitely easier to use in a stationary display with a decent power supply, but if you want to make it portable like in the radar speed sign costume, you’ll likely need some quality lithium batteries and a charge controller.

These can be used for practical purposes too, of course. Public displays often need to be large and bright to be read at a distance, and with a little bit of diffusion, it looks like these digits can be read from quite a ways away. At 188x92mm per digit, these could be used for those “Now Serving Ticket #” displays, or even to create a gas price display for your garage or carport, showing you the average price nearby! With the flexible design and bright LEDs, we’re sure these will end up in all sorts of unusual places.

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If you haven’t learnt to solder why not make it your first challenge of 2024? This printed circuit board (PCB) Airplane with Flashing LED kit could be the perfect place for you to start!

It has numerous features that we think are excellent for beginners at soldering. Most of the components are through-hole meaning they are larger, easier to handle and can be positioned through their mount holes which hold them in place a little while you solder.  The only surface mount components are the large battery holders for one coin cell on each wing and these have large pads which will be straightforward to assemble. The Airplane has numerous LEDs and 2 integrated circuits (ICs or ‘chips’), a classic combination of a 555 timer and a CD4017 decade counter. You don’t need to know anything about those ICs to assemble and operate this kit but they are a classic combination and the circuit would make a great research project for those new to electronics.

The ICs are mounted into sockets which are soldered into place. This again is excellent for those newer to soldering as you are less likely to damage the ICs through overheating when soldering. The two PCBs slot together and you get a little experience soldering aligning pads to make a mechanical and electrical connection between the PCBs.

It’s a great little challenge and you end up with a nice desk toy that you can be proud of as a first soldering project!

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