You’re certainly with how the Raspberry Pi is a great board that can do much of the work of an actual computer without the bulk or expense. What about the other end of the spectrum — how does the Pi perform as a hardware controller? As with any microcontroller solution, if you want your Raspberry Pi to control more than very low current levels you need extra hardware. The Samur Raspberry Pi Expansion MainBoard takes on this challenge, greatly extending the abilities of the Pi’s expansion header.
It features 15 relays rated for 250VAC and 10A or the same 10A current flow at 30VDC. The obvious application would be turning on and off appliances or lighting in a home automation setting, and with a Raspberry Pi (not included) powering it, your control options are virtually unlimited.
If that doesn’t present enough control options, the board also features 8 digital inputs for AC power (currently listed at only 250VAC, however a 120VAC option will be added) along with 6 inputs for 12 VDC. It also has accommodation for I2C, 1Wire, and an NRF24L01+ module for wireless communication.
While what’s shown here is quite capable, if you just need relays for your Pi to handle more power, you might also check out the Mega-IO Raspberry Pi Expansion Card featured earlier this year.
STEM education covers four specific disciplines in one curriculum: science, technology, engineering, and mathematics. In our modern age, these skills are in high demand, and makers everywhere are trying to pass this valuable knowledge on to the next generation.
The original model, known as the ARM-1 from 1Durian.Tech set out to empower educators with a functional robotic arm that could teach the basics of C++ programming and how to use a microcontroller.
With the success of the initial model, they have since released the ARM-2, which is an upgraded version of the robotic arm. This newer version includes everything the original had, along with some crisp new features.
The goal is to teach students basic programming skills through tutorials on how to utilize the microcontroller. There are five included lessons surrounding the coding that include digital control, pulse width modulation, and serial communication, among others.
The robotic arm helps students learn basic knowledge of the servo motors the complexities of single and multiple servos control. There is also a tutorial on teaching and playback mode, an up-and-coming technology used in the robotics industry to save time and increase efficiency.
The enhanced version of the arm adds WiFi control and programming options. There is also analog feedback from the servo motor, XYZ-Axis control, and additional learning modules for educators. The kit comes with the ARM-2 fully assembled, along with a power supply, USB Micro-B, and a PS2 controller for manipulating the arm.
Vacuum Fluorescent Displays (VFDs) aren’t something you work with every day. They are often found in car radios and emit a green or blue light with high levels of contrast. Given these characteristics, it’s not a stretch to think they would make a great display for a clock.
The folks at Akafugu Corporation are selling a kit for this concept in the form of the VFD Modular Clock version IV-6. VFDs, which are similar to vacuum tubes, each contain a single digit so this modular kit includes six IV-6 tubes. You can also opt for an option without the tubes if you have them already. The baseboard is powered by an ATMega32U4 microcontroller with a high-voltage VFD driver that lights up the display shield above the board.
The kit comes pre-programmed with the Arduino Leonardo bootloader and firmware. If you would like, it can be reprogrammed from the Arduino IDE open-source firmware. The finished clock is powered by a 5V USB mini-b connector that works with a computer.
You can also utilize Four Letter Word functionality. It comes with the word association database EEPROM if you would rather display words instead of numbers. Finally, an acrylic enclosure is available separately for those who would like to opt for it.
The OKAY is an analog squarewave synth, ideal for DIY fanatics who want to make big basslines and searing leads! It has a full range of tactile switches and is super portable thanks to being battery powered, so if you need a squarewave synth to go, OKAY is where its at!
The OKAY synth can be played at home or on the move, as it comes with a built in amplifier, speaker and audio output for headphones or recording. You can select through a full spectrum of tones over 6 octaves, mapped across 2 full octaves of keys — for wide-ranging playability off the back of a 9V battery!
Squarewave synths are the go-to sound if you remember the days of Commodore 64, Atari ST and Amiga — making chiptunes on trackers! There is no sound like it, and using the audio output gives you the chance to run it through some pedals and outboard effects.
This educational, hack-able, 3D-printable synth hales from San Fransisco, California and comes in kit form, with PCBs, electronics components and assembly guide. If you own a 3D printer, you have access to all of the STL files on Thingverse to create your own keys, enclosure and other mechanical parts.
You can find out all you need to know about the OKAY 2 and its development here.
The Power Harvesting Challenge has begun! This is the newest stage of the 2018 Hackaday Prize, and the goal is simple: build a module that harvests ambient power for applications, and show your module powering a project. Power harvesting can include getting energy from sources like thermal, wind, solar, ambient light, etc.
This challenge runs now through July 16th, and twenty entries will receive $1,000 and move on to the finals to compete for one of the five top prizes including the $50k grand prize. Let no idea go unexplored — follow your creativity and submit your idea, image, documentation, and four build logs to qualify.
If you need some inspiration for your own project, take a look at the power harvesting projects submitted thus far, and check out the Tindie sellers who have already entered their own projects into the running:
There’s no denying the convenience of wireless functionality. Combine this with a helpful display, and you have a match made in heaven. The Espruino Pixl.js seeks to fill these needs as a smart Bluetooth display that you can wirelessly program using JavaScript.
Monitor other Bluetooth LE devices, create a wireless display, a conference badge, or even just display code status on the screen. The device is designed to use the Arduino footprint, allowing it to interface with a massive amount of already existing Arduino shields while using the LCD and buttons.
The Tindie seller, Gordon Williams, wanted to make a device that was readable in sunlight and easy to connect wirelessly. It utilizes Web Bluetooth which removes the need to install any software on your computer. You can head to the device’s website, connect instantly, and start writing code. There’s even a graphical programming language if you prefer not to use JavaScript.
The design is based on Puck.js, which we’ve featured in the past, and provides Bluetooth LE peripheral, central, and advertising support.
Wouldn’t it be nice if we could just channel electricity from our fingertips? Imagine how much easier it would be to power devices, check components, and charge our phones. While we can’t offer those kinds of superpowers, Tindie seller Sensing is offering the next best thing.
The Handheld Power Supply is a portable device capable of supplying up to 1 W, with 1.2-36 VDC variable open circuit voltage, at up to 1 A output current.
A handy portable power supply like this isn’t something you see every day, which is why this seller decided to make his own, a story often familiar to makers out there who invent their own solutions.
This rechargeable handheld power supply is used for testing components on the go, but it can also charge or power devices via a USB connection. It’s not quite electricity at your fingertips, but it will do just fine.
Somewhere between the Omnichord and the Stylophone sits the Le Strum — a superb MIDI device designed to replicate the melodic playability of a guitar, with the ease of single note chord playback. It’s pocket-sized, but full on features, and takes making music back into realms of pure joy.
Le Strum comes with 36 chord buttons, and a metallic strum plate to trigger individual notes by using the built-in stylus. An astonishing 84 different chords are available, including major, minor, dominant 7th, major 7th, minor 7th, augmented and diminished for 12 root notes. It is able to replicate a guitar string layout, simple triads, and an organ mode which can send your bass part over an alternative MIDI channel.
The Le Strum has been embraced by many professional musicians and producers as an exceptional alternative to the MIDI keyboard. Here we see Grammy-nominated producer James Wiltshire of the Freemasons and F9 Audio demoing it in his studio:
The Le Strum has been used by Michael Lovett of NZCA Lines, for his ambient soundtrack to this rather steamy video:
Renier van der Lee is the father of three kids, a technology enthusiast, and a self-proclaimed “gentleman farmer,” which sounds incredibly official on its own. He is also a Tindie seller who created the award-winning Vinduino sensor, which has seen massive growth and sales both on Tindie and beyond since its inception.
Join us as we explore the history and proliferation of this unique and endlessly useful device that has a huge impact on water conservation and savings for growers.
What is Vinduino, and How Does it Work?
Vinduino is a water-saving irrigation project for vineyards, but it has applications for all types of growers who live in drought-ridden countries. Vinduino utilizes a gypsum soil moisture sensor to accurately measure the moisture present around the roots of a plant.
It was originally designed for use in vineyards, where it can be connected to several long-range RF LoRA modules and charged by solar power. All of this is connected to the irrigation system. When the sensor detects a drop in moisture, the sprinklers turn on, and not a moment before.
Renier first tested his VInduino installation on his own vineyard. Prior to the creation of Vinduino, he was spending over $4,300 each year on a vineyard management company to ensure his vines were watered.
Once he switched over to Vinduino, he didn’t need their assistance anymore. Over the course of a single year, he managed to save 430,000 gallons of water, which equates to $1,925 in cost savings. The entire installation costs $635. It offers a great return on the investment almost immediately and represents a viable solution for the ongoing water shortages in California and across the world.
What Does The Future Hold?
Since winning the Hackaday prize, Reinier has been moving forward with improvements and enhancements to the Vinduino project. In June of 2015, the project went open source. Just two years later, a new Vinduino LLC office location opened in Temecula, CA.
The original design was powered by WiFi, but it was soon discovered that the range of this technology wasn’t sufficient for entire vinyards. Semtech partnered with Vinduino to bring their unique wireless solution to vineyards around the world. Their LoRA wireless radio technology empowers Vinduino to measure data in real-time and deliver it directly to vine growers.
Here’s how this combination of technology works:
Each zone houses a remote sensor station platform and individual sensors of various depths. The resistive solid-state sensors respond to the moisture range for agriculture (0 to 70 kPa) at defined intervals. The LoRa transceiver sends a message packet to any gateway that’s in range.
The gateway, which is designed for public or private LoRaWAN networks, can support up to 1,000 sensors in a six-mile radius. The gateway then connects to a router or modem for internet access.
The packet is forwarded to the vineyard management application housed in a cloud server or dedicated server platform.
The smart irrigation software presents the data on a web interface or mobile app. It can be customized to open or close irrigation valves based on readings.
Vinduino has expanded the technology to included management systems for other crops, such as citrus orchards. As the company and the technology continues to grow, more and more farmers are embracing it for water conservation, growth optimization, and better irrigation management overall.
Sound mixers can be daunting devices. With a wide range of knobs and dials, they accomplish audio miracles. Sometimes, though, you just need a simple solution that can achieve similar results. Rakimix bills itself as a “simple but proficient mixer” which includes 4 controllable channels and one auxiliary channel.
The device can be daisy-chained with another Rakimix or any other mono audio source to create larger channel count mixers. The channels have a level control that ranges from off to +10dB gain. Mute switches allow you to keep level settings and mute the sound on individual channels.
The master volume adjustment works across the four main channels but does not affect the auxiliary input. The auxiliary input is usable with any mono audio signal up to 4Vpp. The output signal is a mix of the 5 channels transmitted to the tip and ring of a stereo output. You can use a mono or stereo cable on the output.
To power the device, you will need a 9V PP3 battery to use with the battery-barrel jack connector included in the kit. If you prefer a power supply, it should be rated +8V to +12V DC and have a center positive barrel jack.
The Rakimix kit comes with a user-friendly assembly guide that you can also view online with pictures, hints, and tips. It’s classified as an intermediate DIY kit that requires a soldering iron and a pair of flush cutters. Beginners shouldn’t be afraid to give this a shot, however, as the kit comes with a cheat sheet to identify the resistors based on their color bands.
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Sound mixers can be daunting devices. With a wide range of knobs and dials, they accomplish audio miracles. Sometimes, though, you just need a simple solution that can achieve similar results. 
The master volume adjustment works across the four main channels but does not affect the auxiliary input. The auxiliary input is usable with any mono audio signal up to 4Vpp. The output signal is a mix of the 5 channels transmitted to the tip and ring of a stereo output. You can use a mono or stereo cable on the output.