Hacklet 85: Alternative Audio Amplifiers

When you think of amplifiers, you’re probably thinking of audio or some big ‘ol power amps for radios. While interesting, there are some very interesting ‘alternative’ amplifiers floating around hackaday.io that are more than just power amps, and exceedingly useful, to boot.

1601181393316190625[Ronald] bought an XMS amplifier a few years ago, and although it worked well, every time he changed the input, the loudness had to be toggled. One thing led to another, and he realized this amplifier had a four-channel audio processor that could be controlled by I2C. This was the beginning of his Network Amplifier.

Inside the box is a Raspberry Pi that controls a PT2314-based amplifier. Also included is a 2×16 character LCD, a few LEDs, switches, and a rotary encoder.  There was an Android app that controlled the amplifier, but this was discarded for a better looking web-based solution. Now [Ronald] has every audio source available over WiFi.

973501443636885535What if you want an audio amplifier without a speaker? Wait, what? That’s what [DeepSOIC] is doing with his experiments in ion wind loudspeakers.

‘Ion wind lifters’ have been around for decades now, mostly in the labs of slightly off-kilter people who believe this is the technology aliens are using to visit earth. Nevertheless, ion wind lifters produce an airflow, and if you make that wind variable, you get sound. Pretty cool, huh?

The amplifier for this project uses a tube to modulate kilovolt supply through the ion ‘blower’. Does it work? Sure does. [DeepSOIC] got a piece of 0.2 mm nichrome wire to discharge ions into the air, after which the ions drift into the second electrode. The result is sound, and the entire project is built deadbug style. It really doesn’t get cooler than this.


2981611414932529525Continuing with the tube amp trend, [Marcel] built the cheapest little tube amp around.

The design of an audio tube amp is fairly simple business. First, you start with a big ‘ol transformer, and rectify the AC into DC. This gets fed into a preamp tube, and this is fed into a bigger power tube.

In about 50 years of development, tube designers had the technology down pat by the mid 1950s, and triode/pentode tubes were created. This allowed tube designers to condense two amplifier stages into a single tube. While this setup was usually used for cheap, toy-like electronics, you can still buy the ECL82 tube today.

[Marcel] took one of these tubes, added a rectifier tube, transformer, and big cap to create the simplest possible tube amp. Use it for guitars, use it for hi-fis, it’s all the same. It’s not going to sound great, but it is a very easy amp to build.

All of these interesting audio amplifier projects are curated on this new list! If you have a build that amplifies sound in an interesting way, don’t be shy, just drop [Adam] a message on Hackaday.io and he’ll add it. That’s it for this week’s Hacklet. As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Hacklet 83 – Tiny Robot Projects

Hackers, makers, and engineers have been hacking on robot projects since the era of clockwork mechanics. Any robot is a cool project, but there is something particularly attractive about small ones. Maybe it’s the skill required to assemble them, or perhaps it’s the low-cost. Either way, there are lots of palm-sized robot projects on Hackaday.io. This week on the Hacklet, we’re going to highlight a few of them!

tinyrobot2We start with the granddaddy of them all, [shlonkin] and Tiny robot family. [Shlonkin] built line following robots that can hide under a US half-dollar coin. The robots are simple circuits – an ATtiny85 with an LED and pair of phototransistors. The code is provided both in Arduino’s wiring, and in straight C++. Two coreless motors, normally used in cell phones vibrators or quadcopters, provide the locomotion. These robots only know one thing – moving forward and following a line. They do it well though! We love this project so much that we hosted a tiny robot workshop at the 10th anniversary back in 2014.

toteWhen it comes to tiny walking robots, [Radomir Dopieralski] is the king. Many of his projects are small biped, quadruped, or even hexapod robots. He’s done things with 9 gram nano servos that we thought were impossible. Tote, an affordable spider robot, is his latest creation. Tote is a four-legged bot utilizing 12 9 gram servos. [Radomir] created a custom PCB for Tote, which acts as a carrier for its Arduino Pro Mini Brain. This robot is easily expandable – [Radomir] has experimented with the Teensy 3 series as well. Controlling the robot can be anything from an ESP8266 to an infrared remote control.

botbot[Alan Kilian] may well have the ultimate tease project with Hand-wound inductors for a tiny robot. [Alan] was using some tiny GM-10 motors on his micro-bot. The motors didn’t have inductance for the locked-antiphase drive controller. His solution was to wind some coils to provide a bit of added inductance. The mod worked, current consumption dropped from 116 ma to about 6 ma. We want to know more about that ‘bot though! It’s controlled by a Megabitty, [Monty Goodson’s] ATmega8 controller board from sometime around 2003. The lilliputian board has been very popular with the nano sumo crowd. Other than the controller, motors, and the plywood frame, [Alan] has left us guessing about his robot. If you see him, tell [Alan] to give us more info on his micro robot’s design and construction!


espbot[Ccates] jumped on the tiny robot bandwagon with Tiny wi-fi robot. Rather than go with an Arduino for control, [Ccates] grabbed the popular ESP-8266 WiFi module. The construction of the bot is inspired by [shlonkin’s] tiny robot family up above. This bot is controlled by the Xtensa processor embedded in the ESP-8266. Since it only drives forward, it only takes two GPIO pins to control the transistors driving the motors. Even the diminutive ESP-01 module has enough I/O for that. We’d love see some sensors and a full H-bridge on this micro beastie!


If you want to see more palm-sized robot projects, check out our new tiny robot projects list! These ‘bots are small, so I may have missed yours. If that’s the case, don’t be shy, just drop me a message on Hackaday.io. That’s it for this week’s Hacklet. As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Hacklet 82 – Halloween Hacks 2015

Halloween is when the ghouls start haunting and the hackers start hacking. All hallows eve is the perfect holiday for eerie blinking LEDs, spooky audio oscillators, and wild animatronics. We had a double dose of Halloween hacks last year on the Hacklet. This year we’re bringing you even more of the best Halloween hacks on hackaday.io!

eyes1We start with [dougal] and Halloween Blinky Eyes. [Dougal] wanted to create the effect of creatures peeking at you from the dark corners of the room, and he’s certainly nailed it. A strip of WS2812 LEDs is the trick here. Pairs of LEDs light up, blink, and fade away like spooky eyes. The Strip is controlled by a Particle Core using Adafruit’s NeoPixel Library, though [Dougal] plans to move to the FastLed library. Everything is powered by a USB power pack. This hack isn’t much to look at with the lights on, so check out the video to see these eyes really shine!


witch1Next up is [controlmypad] with Blair the Witch Project. A normal trip to Home Depot turned paranormal when [controlmypad] spotted an awesome witch decoration. The free-standing mannequin had some basic animatronics and the all important manual trigger. [controlmypad] already had a discarded electric wheelchair. After replacing the chair batteries he modified it with a Sabertooth 2×32 Motor Controller and a standard radio control receiver. A spare channel was connected to Blair’s manual trigger. An aluminum tube joins the witch and the scooter. The hardest part of this hack was keeping Blair’s skirt out of the scooter wheels. Home Depot to the rescue! A simple hoop made of lawn edging plastic keeps the fabric and wheels apart.



[Alex Cordonnier] and his team participated in Boilermake 2015, a 24 hour Hackathon at Purdue University. The fruit of their labor is Trick or Tweet, the tweeting Jack-o’-lantern. Yes folks, we now have the internet of gourds. Hiding inside Trick or Tweet is a Raspberry Pi and a Pi Camera. The pumpkin itself is also a giant capacitive touch switch. Touching the pumpkin triggers a count down after which Trick or Tweet snaps a photo. It then adds some spooky Halloween overlays, a pun or two, and throws the whole thing up on twitter @PumpkinPiPics. [Alex] hasn’t uploaded the code yet, but we’re guessing it consists of a few Python scripts. Pretty awesome for 24 hours of work!


hariSometimes Halloween hacks take on a life of their own. That’s exactly what happened when [Hari Wiguna] sat down with a few parts he ordered from China. Happy Halloween 2015 is the result. [Hari’s] order included some potentiometers, a two color OLED display, and some Arduino clones. In no time [Hari] had three pots wired up to the Arduino’s analog inputs. The OLED quickly followed, displaying graphics via the Arduino’s I2C bus. He really wanted a Jack-o’-lantern though. It took a bit more tweaking, but eventually [Hari] was successful. The first pot sets eye size.  The second controls eye rotation. The third pot changes the width of Jack’s mouth. [Hari] has all the code for this hack up on his most recent project log.

Not spooked enough? If you want to see more Halloween projects, check out our newly updated Halloween hacks list! Did I miss your project? Don’t be shy, just drop me a message on Hackaday.io. That’s it for this week’s Hacklet; As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Hacklet 81 – Tracked Projects

Sometimes wheels just don’t cut it. When the going gets tough, the tough make tracks. Continuous track drive systems – aka tank treads, or tracks, have been around for centuries. The first known use in relatively modern history is a system designed in 1770’s by [Richard Lovell Edgeworth]. Since then there has been a slew of engineers, hackers, and makers who have contributed to this versatile drive system. Today, tread systems find their way into plenty of robotics and transportation projects. This week’s Hacklet is all about some of the best track drive projects on Hackaday.io!

track1We start with [jupdyke] and Modular Continuous Track System. [Jupdyke] has made a project out of making the tracks themselves. These tracks are strong – shore 70A urethane rubber is no joke! Quite a bit of research and experimentation has gone into this project. [Jupdyke] started with 3D printed parts, before moving on to molded 2 part rubber. The rubber is cast in custom machined aluminum molds. The molds are even heated to ensure a quality casting. Rubber alone doesn’t make a track though. The backbone of these tracks are machined steel pins. The pins go through the treads and connect through roller chain components. We’re betting a set of these tracks could easily carry a person!

robot-tankNext up is [williamg42] with Expandable Ruggedized Robotic Platform. [Williamg42] describes this vehicle as “able to operate in harsh environments”. We would shorten that to “It’s a beast”. Some incredible machine work has gone into this robot, especially on the suspension and idler wheels. Everything is made of metal – the frame is 8020 aluminum extrusion covered in plates. The suspension is aluminum and steel. Motors are mini-CIM motors. This robot isn’t lacking on brains, as a BeagleBone black controls it through a custom cape board. Next time we go out on a desert trek, we want this ‘bot at our side!

ttbn-alphaFrom the mind of [TinHead] comes TTBN Alpha, a TelePresence robot. TTBN alpha is based on a Raspberry Pi. Rather than start with Raspbian, [TinHead] built his own lightweight Linux distribution with buildroot. Control is through a web interface. The operator’s view of the world is through the electronic eye of a Logitech C110 webcam. [TinHead] printed his own tracks, using straightened paperclips as pins. Two servos modified for continuous rotation serve as the main drive motors.



Finally we have [Hendra Kusumah] with Surveillance Robot Camera (SUROCAM). SUROCAM was [Hendra’s] project for both the 2014 and 2015 Hackaday Prize. The chassis is based upon the common RP5 robot kit. This robot’s DC motors are driven by the classic L298n driver chip. Unlike TTBN Alpha above, SUROCAM uses a full Raspbian install, so this Pi is ready for anything. The code is written in Python, and pagekite and ngrok to help make connections to the outside world.

If you want to see more tank treaded rovers, check out our new tracked projects list. Did I miss your project? Don’t be shy, just drop me a message on Hackaday.io. That’s it for this week’s Hacklet; As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Hacklet 79 – USB Projects

Universal Serial Bus was created to simplify interconnecting computers and peripherals. First released in 1996, hackers and makers were slow to accept this strange new protocol. Parallel and serial ports were simpler, worked great, and had decades of hacking with thousands of projects behind them. As the new standard caught on in the mainstream, RS-232 and parallel ports started disappearing. “Legacy free” PC’s became the norm. Hackers, Makers, and Engineers had no choice but to jump on the bandwagon, which they did with great gusto. Today everything has a USB port. From 8 bit microcontrollers to cell phones to children’s toys. This week’s Hacklet is about some of the best USB projects on Hackaday.io!

two partsWe start with [Michael Mogenson] and Two Component USB Temperature Data Logger, which may be the simplest USB device ever made. [Michael] isn’t kidding. This data logger consists of just a Microchip PIC16F1455 microcontroller and a USB connector. Microchip’s datasheet calls for a capacitor to smooth out power, but [Michael] made it work without the extra part. He used M-Stack by Signal 11 to implement the USB stack. Once connected to a PC, the PIC enumerates as a serial port device. It then sends its die temperature of the PIC once per second. It could do more, but that would probably require adding a few more components!

tester1Next up is [davedarko] with USB cable tester. Dave recently spent some time installing USB RFID readers. These devices were only a few meters away from the computer controlling them. Even so, the power and USB data cables had to run through pipes and in some cases under water. It wasn’t fun troubleshooting a device to find that it was a shorted USB cable causing the problem. [Dave’s] solution is a tiny coin cell powered board that tests each of the 4 wires in a standard USB 2.0 cable. The board runs on an ATtiny45 microcontroller. [Dave’s] current iteration has footprints for mini and micro USB connectors, along with the standard USB-A.


tester2[MobileWill] has a USB Tester of his own. This USB tester checks current consumption and rail voltage. It does this by connecting in-line with the device under test. It’s perfect for troubleshooting why your PC’s USB port goes into over-current protection every time you plug in your device. The tester is modular – you can use the base board with your own multimeter, or grab [Will’s] tester backpack and see the results right on the built-in OLED display. USB Tester is [Will’s] entry in the 2015 Hackaday Prize.


tbdFinally, we have [ajlitt] with Tiny Bit Dingus (TBD). TBD is a USB interface to 6 wires. Think of it as a tiny version of the bus pirate. This lilliputian board holds a Freescale KL27Z ARM processor, which has more than enough power to handle things like I2C, SPI, PWM, or just about any other way to send data or wiggle wires. [Ajlitt] started this project as an excuse to learn KiCAD and gain some experience with surface mount solder stencils. The result is an absolutely tiny board that is all but lost in a USB socket. Programming is handled with the mbed library, though you can always use Freescale’s native tools. Flashing code on the TBD is easy with kut, a chrome browser plugin.

If you want to see more USB projects, check out our new USB projects list. Did I miss your project? Don’t be shy, just drop me a message on Hackaday.io. That’s it for this week’s Hacklet, As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Hacklet 77 – Projects that Tweet

Since it’s launch way back in 2006, Twitter has become a magnet for techies. Maybe it’s the simple interface, maybe it’s the 140 character limit. Whatever the reason, you can find plenty of hackers, makers, and engineers tweeting about their daily activities. It didn’t take long for folks to start incorporating Twitter into their projects. Ladyada’s Tweet-a-watt is a great early example of this. This week’s Hacklet is all about some of the best tweeting projects on Hackaday.io!

dogbarkWe start with [Henry Conklin] and A Twitter account for my dog. [Henry’s] dog [Oliver] loves to bark and finding a solution became his entry to The Hackaday Prize. Rather than bring Cesar Millan in, [Henry] decided to embrace [Oliver’s] vocalizations by sending them up to the cloud. A Raspberry Pi with a USB microphone uses some custom Python code to detect barks and ruffs. The Pi then sends this data to Twitter using the python-twitter library. The Pi is connected to the internet via a USB WiFi dongle. You can see the results of [Henry’s] work on [Oliver’s] own Twitter page!

dectalkerNext up is [troy.forster] and tweetie-pi. Rather than constantly check his phone or computer, [Troy] wanted a device to read his tweets. A bit of NodeJS code later, and tweetie-pi was born. A Raspberry Pi connected to the internet pulls data through the Twitter stream API. When tweets directed at a pre-configured username are found, the data is sent to a an Emic 2 text to speech module. The Emic reads in that classic DECtalker style voice we all know and love from the movies. [Troy] even added code to properly handle usernames and retweets.


homeauto[SirClover] joined the internet of things by creating Home automation system with Twitter, his entry in the 2014 Hackaday Prize. This home automation system is based around an Arduino Leonardo and an Ethernet shield. [SirClover] rolled his own custom PCB to handle relays, a Cds cell, and a 2×16 character LCD. The system can be accessed through a simple web interface. This allows the user to open or close blinds, turn on lights, all that great smart home stuff. Every time it executes a command, the home automation system reports status to Twitter.

das-cubeFinally we have [Jakob Andrén] with A danceable notification cube, which is [Jakob’s] entry in the 2015 Hackaday Prize. The cube itself is a translucent box that contains a metric crapton of LEDs. 148 Neopixels and 12 3W power LEDs to be exact. All these LEDs are driven by a Teensy 3.1, which serves as the main processor for the entire system. The Teensy reads position data from an MPU6040 IMU. This allows it to change brightness and color as the box is moved around – or “danced”. An ESP8266 provides the cube with data from the interwebs, specifically Facebook and Twitter. The cube lights up and flashes whenever it receives a message.

If you want to see more tweeting projects, check out our new projects that tweet list.  Did I miss your project? Don’t be shy, just drop me a message on Hackaday.io. That’s it for this week’s Hacklet, As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Hacklet 74 – Well Balanced Projects

Balance: we humans take it for granted. Without the sense of balance provided by our inner ears, we would have a hard time standing or walking around. What’s easy for us can be very hard for machines though. Projects that balance things have long been a challenge for engineers, makers and hackers. And rightly so, as building a machine to keep an object in balance often requires some novel electronic and mechanical solutions. This week’s Hacklet is all about projects that keep an object – or themselves – in balance.

wheelWe start with [Manuel Kasten] and Balance Wheel. Inspired by a project at Chaos Communication Congress, [Manuel] created a hack that looks timeless. A stainless steel ball is balanced on top of a wooden wheel. The system detects the ball’s position using a solar cell. More light on the cell means the ball is slipping off the wheel. The system counteracts this by spinning the wheel to oppose the falling ball. In the old days this would have been an analog system. [Manuel] made things a bit more modern by using an ATmega644p processor. The video shows the wheel spinning a bit fast, as the system was tuned for a ping pong ball rather than a heavy steel roller.

sidewayNext up is [Jason Dorie] with Sideway. Sideway is a two-wheeled skateboard that self-balances. One of the best parts of this project is that most of the mechanical components are from electric scooters, which means they are easy to source. The frame is even easier: A solid piece of plywood supports the rider and all the electronics. Two scooter motors are driven by a Sabertooth 2x32A motor controller. A Parallax Propeller performs the balancing act, obtaining IMU data from an ITG3200 digital gyro and an ADXL345 accelerometer. Speed is controlled by leaning forward and back, like a Segway. Steering is controlled by a Wiimote nunchuck. Sideway is powered by 3 cell LiPo batteries. [Jason] says this ride gets a lot of attention every time he takes it out.


balance-robot[Dominic Robillard] developed his Stair-climbing self-balancing robot as part of his masters degree at the University of Ottawa. We don’t know what grade his advisors gave him, but we give this project an A+. The robot is a 4WD off-road monster. Two heavy-duty drive motors give it tank style steering. The most impressive part of the robot are the two arms which allow it to roll its entire chassis up and over obstacles which would stop much larger robots. [Dominic’s] robot isn’t just statically balanced though – it can rear up and ride on two wheels Segway style. If it does tip over, the arms will lift it right back up!


terrabalanceFinally, we have [Paul Bristow] with Terabalance. [Paul] got his hands on an early copy of the TeraRanger One, a Time of Flight (ToF) sensor developed at CERN. He decided to test it out by using it to balance a ping pong ball on a wooden bar. The sensor had to be slowed down quite a bit in this application, data is only read about 1000 times a second and averaged. An Arduino reads the distance data from the sensor and uses that data to drive a hobby servo. No PID loops here, in fact, Terabalance is a great example of how a proportional only system will hunt forever. That said, it is good enough to keep the ball on the balance bar.

There are a plenty of balancing projects on Hackaday.io. If you want to see more, check out the new well balanced project list! Did I miss your project? Don’t be shy, just drop me a message on Hackaday.io. That’s it for this week’s Hacklet, As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!