Redesigned Bike Light Controller

[JP] was looking for a bicycle light to do some night biking around his home. He found a reasonably priced light that suited his needs, but when he started using it he found that the controller was a little lackluster. To solve some of its problems, he ended up building his own lighting controller from scratch.

The original controller’s main problem was that the it didn’t debounce the input from the single pushbutton. This meant that a single press of the button might cause it to cycle through two or three different modes, which was inconvenient and annoying. The new controller took care of this along with implementing several new brightness modes and a “strobe” mode for commuting to work to help alert other drivers of [JP]’s presence on his bicycle.

While [JP] notes that an Arduino would have been very easy to use in this situation, it wouldn’t have fit in the original enclosure. He went with an 8-pin ATtiny45, which was perfectly sized for what he needed. Everything fit together perfectly and is much more useful than the original. Maybe next he could pair it with a light that is even brighter than the one he’s currently using.

Inexpensive AVR Programmer Made From Five Components

If you want to program an AVR chip as inexpensively as possible, then [Ian’s] solution might just be for you. He built an AVR programmer using only four components. This design is based on the vusbtiny AVR programmer design, with a few components left out.

[Ian’s] design leaves out two of the resistors and two diodes, leaving just four components. These include a 1.5k resistor, a small capacitor, a USB connector, a six pin header, and an ATtiny45. He admits that this may not be exactly up to USB spec, but it does work.

This is one of those projects that is really an exercise in “will it work?” more than anything else. The fact that you need to first program an AVR chip means that this wouldn’t be useful in a pinch, because you would already have to have a working programmer. Nonetheless, it’s always fun to see what can be done with as little as possible.

Solderless Noise-o-Tron Kit Makes Noise at Chicago Makerfaire

Noise-o-Tron

Anyone who’s manned a hackerspace booth at an event knows how difficult it can be to describe to people what a hackerspace is. No matter what words you use to describe it, nothing really seems to do it justice. You simply can’t use words to make someone feel that sense of accomplishment and fun that you get when you learn something new and build something that actually works.

[Derek] had this same problem and decided to do something about it. He realized that in order to really share the experience of a hackerspace, he would have to bring a piece of the hackerspace to the people.  That meant getting people to build something simple, but fun. [Derek’s] design had to be easy enough for anyone to put together, and inexpensive enough that it can be produced in moderate quantities without breaking the bank.

[Derek] ended up building a simple “optical theremin”. The heart of this simple circuit is an ATTiny45. Arduino libraries have already been ported to this chip, so all [Derek] had to do was write a few simple lines of code and he was up and running. The chip is connected to a photocell so the pitch will vary with the amount of light that reaches the cell. The user can then change the pitch by moving their hand closer or further away, achieving a similar effect to a theremin.

[Derek] designed a simple “pcb” out of acrylic, with laser cut holes for all of the components. If you don’t have access to a laser cutter to cut the acrylic sheets, you could always build your own. The electronic components are placed into the holes and the leads are simply twisted together. This allows even an inexperienced builder to complete the project in just five to ten minutes with no complicated tools. The end result of his hard work was a crowded booth at a lot of happy new makers. All of [Derek’s] plans are available on github, and he hopes his project will find use at Makerfaires and hackerspace events all over the world.

The p.u.l.s.e Parking Light

Pulse[Anool]’s brother loves his motorcycle, and when he came across a ‘breathing LED’ mod for the brake light, he had to have one. Being tasked with the creation of a pretty cool mod, [Anool] came up with p.u.l.s.e., an extremely small LED controller and a slight tip ‘o the hat to Pink Floyd and the second or third greatest CD packagings.

The circuit is a slightly Apple-inspired mod for the  parking light that keeps the lamp fully lit when the Neutral Detect line on the bike is high, and slowly pulses the LED in a ‘breathing’ pattern when the Neutral Detect line is low. Not a lot of logic is needed for something this simple, so [Anool] turned to the ATtiny45 and the Arduino IDE to accomplish his goal.

[Anool] created a circuit in KiCAD that would plug in to the lamp socket of his brother’s bike. A cluster of LEDs replace the T10 lamp inside the parking light, and a small amount of code takes care of the logic and breathing effect. It’s a great mod, and the astonishingly small size of the board puts him in the running for the smallest Arduino we’ve ever seen.

Videos of the light in action below.

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Build Your Own Radio Clock Transmitter

NIST

Deep in the Colorado foothills, there are two radio transmitters that control the time on millions of clocks all across North America. It’s WWVB, the NIST time signal radio station that sends the time from several atomic clocks over the airwaves to radio controlled clocks across the continent. You might think replicating a 70 kW, multi-million dollar radio transmitter to set your own clock might be out of reach, but with a single ATtiny45, just about everything is possible.

Even though WWVB has enough power to set clocks in LA, New York, and the far reaches of Canada, even a pitifully underpowered transmitter – such as a microcontroller with a long wire attached to a pin PWMing at 60kHz – will be more than enough to overpower the official signal and set a custom time on a WWVB-controlled clock. This signal must be modulated, of course, and the most common radio controlled clocks use an extremely simple amplitude modulation that can be easily replicated by changing the duty cycle of the carrier. After that, it’s a simple matter of encoding the time signal.

The end result of this build is an extremely small one-chip device that can change the time of any remote-controlled clock. We can guess this would be useful if your radio controlled clock isn’t receiving a signal for some reason, but the fact that April 1st is just a few days away gives us a much, much better idea.

Miniscule Line-Follower

miniscule-line-follower

Building line following robots is fun and easy. Building a line-follower that is this tiny is a different story. The surprising thing for us is that despite how it looks, this robot whose name is Rizeh doesn’t use wheels to get around. [Naghi Sotoudeh] built the line-follower using two vibrating motors, with needles (not shown above) making three points of contact with the ground.

His website is a little sparse, but hit the downloads page to get a PDF file that serves as the build log. We also downloaded the 32 second demo video which is worth it. The magic-marker track that the bot is circumnavigating isn’t any bigger than the palm of your hand!

Onboard the diy PCB you’ll find two GP2S04 IR reflectance sensors which detect the black line on a white paper. The power-up sequence spends a few seconds calibrating these sensors. Speaking of power, [Naghi] went with a lithium polymer cell from a Bluetooth headset. At the heart of it all is an ATtiny45 which uses its hardware PWM capabilities to drive the two motors.

Of course line-followers rank up there with self-balancers as our favorite robot projects. But by far the ones we love the most are the speed-run maze solvers.

Turn a PC on with a Knock and an ATTiny

knockAttiny

Pressing the power button on your computer usually isn’t too much trouble, unless your computer is stored away somewhere hard to reach. [Joonas] has been hard at work on a solution that would also impress his friends, building a knock sensor to turn on his PC.

For around $10 in parts he put together an ATTiny45 that emulates a PS/2 device, which takes advantage of his computer’s ability to boot upon receiving PS/2 input. The build uses a Piezo buzzer and a 1M Ohm resistor as a knock sensor exactly as the official Arduino tutorial demonstrates, and one of those PS/2-to-USB adapters that are most likely lurking in the back corner of every drawer in your office.

[Joonas] used AVRweb to disable the 8X clock divider so there’d be enough clock cycles for PS/2 communication, then loaded some test code to make sure the vibrations were being detected correctly. You can check out his Github for the final code here, and stick around after the break for a quick video demo. Then check out a similar hack with [Mathieu’s] home automation knock sensor.

Continue reading “Turn a PC on with a Knock and an ATTiny”