Hacklet 74 – Well Balanced Projects

September 11, 2015 by Adam Fabio 1 Comment

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.

We 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.

Next 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.

[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!

Finally, 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!

Logic Noise: Playing In Tune With An Exponential VCO

September 11, 2015 by Elliot Williams 19 Comments

Last session, we use the cheap and cheerful 4046 Phase-locked Loop chip as a simple voltage-controlled oscillator (VCO). It was dead simple, in fact, because the chip has a VCO already built in. There’s one big drawback of the 4046’s VCO; the pitch changes linearly with the control voltage. Ideally, as we’ll discuss in the next sections, we’d like the frequency to be an exponential function of the control voltage (CV), and that’s going to mean a little bit of analog circuitry.

René Schmitz has a fantastic exponential VCO design that’s almost a perfect fit for the Logic Noise series — it’s built with a minimum of parts, it’s a little bit rough around the edges, and at its core is a 4000-series CMOS chip that’s normally used for digital logic applications. The only drawback, from our perspective, is that it uses a dual (positive and negative) power supply. We’ll hack our way around that, and ignore some of René’s otherwise worthwhile refinements in the name of doing something truly quick and dirty. We’ll get 95% of the results with 70% of the work, although it’s easy enough to add on the rest if it strikes your fancy.

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Retrotechtacular: So You Want To Be A Weldor

September 10, 2015 by Kristina Panos 27 Comments

Welding is one of those things that takes minutes to learn and years to master. It requires coordination, strength, and a good pair of eyes. This vocational guidance video from the early 1940s touches on these points and more for those considering careers in welding. The narrator jumps right in, discussing welding types, equipment operation, and employment opportunities in both the welding field itself and other fields that use welding techniques.

Oxy-acetylene welding is one of the oldest methods of fusing metal. A flame fueled by a specific mixture of pure oxygen and acetylene gas heats the metal welding rod and the work piece to plasticity, which allows them to join together. An oxy-acetylene setup can also be used to cut metal, though a special cutting torch with a kind of oxygen turbo boost lever is required. The work piece is heated to red-hot at the point along the edge where the cut will start. The oxygen-rich flame will cut right through the piece.

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Kids And Hacking: Blind Robotics

September 10, 2015 by Al Williams 21 Comments

If you are a Hackaday reader, it is a good bet that when you were a kid there was some adult who infected you with the madness you have for science, engineering, tinkering, or whatever it is that brings you here. Maybe it was a parent or a teacher. For many of us, it was a local ham radio operator. But it was probably someone who had the passion for this kind of thing and you caught it.

Paying that debt forward can be very rewarding. Schools and youth organizations are always looking for people to share their passions with kids and at the right age and the right school, you could be that one push that moves a kid off a bad path.

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Steal This Ham Radio (Technology)

September 9, 2015 by Al Williams 35 Comments

Although I see a lot of wireless projects, I’m always surprised at the lack of diversity in the radio portions of them. I’m a ham radio operator (WD5GNR; I was licensed in 1977) and hams use a variety of radio techniques. If you think hams just use Morse code and voice communications, you are thinking of your grandfather’s ham radio. Modern hams have gone digital and communicate via satellites, video, and many different digital techniques that could easily have applicability to different wireless projects.

Of course, Morse code may have been one of the first digital modes. But hams have used teletype, FAX, and other digital modes for years. Now with PCs and soundcards in common use, hams have been on the forefront of devising sophisticated digital radio techniques.

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Hackaday Links: September 6, 2015

September 6, 2015 by Brian Benchoff 10 Comments

The MeArm is a cool little robot arm that can be controlled with just about any microcontroller. There’s a new version of it up on Thingiverse.

Here’s something to get kids interested in robotics: the GoBox is a robot kit with multiple ‘missions’ delivered monthly. The robot is based on the Raspberry Pi and Scratch – the Apple II and BASIC of today, I guess.

What happens when a popular electronics YouTuber completely debunks a product? Hundreds of dislikes appear on the YouTube videos he made. Hundreds of dislikes from Vietnam appeared on [Dave Jones]’ videos debunking the Batterizer. In fact, more people from Vietnam disliked the video than viewed it. Yes, weird YouTube dislike farms like this exist, and if you can do it on the Internet, you can also pay people to do it on the Internet.

The ESP8266 is slowly becoming a board that’s as easy to use as an Arduino. Now there’s a board that turns it into an Arduino.

The Vintage Computer Festival Midwest was last week, and [chris537a] shot a video of all the cool stuff. [vikram4819] put an album up on imgur. Yes, someone was selling a Sparcbook for $300. I’m holding out for a PowerPC ThinkPad, though…

Washington DC area hackers, don’t forget to RSVP for the Hackaday Meetup on Saturday. Bring a hack to show off and spend the evening socializing with the Hackaday community. Check out the announcement post for more info.

Hacklet 73 – Parallax Propeller Projects

September 4, 2015 by Adam Fabio 17 Comments

In 2006, Parallax, Inc wasn’t new to the electronics business. They’d been around since 1987. Still, for a relatively small company, jumping into custom chips is a big leap. Parallax didn’t just jump into some cookie cutter ASIC, they made their own parallel multi-core microcontroller. Designed by [Chip Gracey], the Parallax Propeller has 8 cores, called cogs. Cogs are connected to I/O pins and other resources by a hub. The Propeller saw commercial success, and continues to have a loyal following. This week’s Hacklet is about some of the best Propeller projects on Hackaday.io!

We start with retrocomputing prop star [Jac Goudsmit] and L-Star: Minimal Propeller/6502 Computer. [Jac] loves the classic 6502 processor. Inspired by [Ben Heckendorn’s] recent Apple I build, [Jac] wanted to see if he could replicate an Apple I with minimal parts. He built upon the success of his Software-Defined 6502 Computer project and created L-Star. The whole thing fits on a Propeller proto board with room to spare. The project uses a 6502, with a Propeller handling just about everything else. The system takes input from a PS-2 keyboard, and outputs via composite video, just like the original Apple I. As you can see from the photo, it’s quite capable of displaying Woz in ASCII. [Jac] has expanded the L-Star to support the Ohio Scientific C1P and CompuKit UK101, both early 6502 based computers.

Next up is [Mike H] with B-BOT. B-BOT is a balancing robot. [Mike] used B-BOT to learn about designing with the Propeller and programming in SPIN, the Prop’s built-in interpreted language. While slower than assembler, SPIN was plenty fast enough to solve the classic inverted pendulum problem. B-BOT’s primary sensor is a Pololu AltIMU-10. This module contains a gyro, accelerometer, compass, and altimeter all on one tiny board. Locomotion comes in the form of two stepper motors. Command and control is via X-Bee radio modules. All the parts live on a custom PCB [Mike] milled using his CNC router.

[Antti.lukats] created Soft Propeller, his entry in the 2015 Hackaday Prize. Soft Propeller doesn’t use a hardware Propeller at all. The core of the system is a Xilinx Zynq-7 chip, which contains an FPGA and a Dual Core ARM A9+ processor. Back in 2014, Parallax released the Verilog HDL code for the Propeller core. [Antti] has taken this code and ported it over the Zynq-7. With 256Kb of RAM, 16 MB of Flash and an LED, the entire system fits in a DIP package smaller than a stick of gum.

Finally, we have [Christian] with Pipman GPS Watch. There’s just something about the Pip-boy from the Fallout video game series. This Personal Information Processor (PIP) has spawned hundreds of projects from cosplayers and electronics hobbyists alike. [Christian’s] version uses a 4D systems TFT LCD to display those awesome graphics. Input comes through a 5 way navigation switch. A GPS and compass module provide all the navigation data Pipman needs. At the center of it all is a Parallax Propeller programmed in SPIN. [Christian] has a working prototype on his bench. He’s now working on modeling a 3D printed case with Blender.

There are a ton of Propeller projects on Hackaday.io. If you want to see more, check out our Propeller 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!