Animated Bluetooth Bike Turn Signals

May 24, 2018 by Tom Nardi 40 Comments

Tired of risking his life every time he had to signal a turn using his hands while riding his bicycle in rainy Vancouver, [Simon Wong] decided he needed something a bit higher tech. But rather than buy something off the shelf, he decided to make it into his first serious Arduino project. Given the final results and the laundry list of features, we’d say he really knocked this one out of the park. If this is him getting started, we’re very keen to see where he goes from here.

So what makes these turn signals so special? Well for one, he wanted to make it so nobody would try to steal his setup. He wanted the main signal to be easily removable so he could take it inside, and the controls to be so well-integrated into the bike that they wouldn’t be obvious. In the end he managed to stuff a battery pack, Arduino Nano, and an HC-05 module inside the handlebars; with just a switch protruding from the very end to hint that everything wasn’t stock.

On the other side, a ATMEGA328P microcontroller along with another HC-05 drives two 8×8 LED matrices with MAX7219 controllers. Everything is powered by a 18650 lithium-ion battery with a 134N3P module to bring it up to 5 VDC. To make the device easily removable, as well as keep the elements out, all the hardware is enclosed in a commercial waterproof case. As a final touch, [Simon] added a Qi wireless charging receiver to the mix so he could just pull the signal off and drop it on a charging pad without needing to open it up.

It’s been some time since we’ve seen a bike turn signal build, so it’s nice to see one done with a bit more modern hardware. But the real question: will he be donning a lighted helmet for added safety?

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Investigating The Tiny Salvaged UPS From A Lightbulb

May 21, 2018 by Tom Nardi 34 Comments

Recently I had the opportunity to do a teardown of a battery-backed LED bulb, and found some interesting details on how the device operated. Essentially, the bulb contained a low voltage DC uninterruptible power supply that would automatically switch between AC power and internal battery as needed. The implications of this seemed pretty exciting. For around $12 at big box retailers, this little bulb could be a cheap and convenient solution for providing fault tolerant power to microcontrollers and other low-power devices.

The teardown was a runaway success, with quite a bit of discussion of the UPS idea specifically. Some people hated it, others loved it. But as we’ve come to expect from Hackaday readers, the comments from both sides of the aisle contained keen observations and invaluable real-world experience. From the safety of the device to the accuracy of the manufacturer’s claims, it seems like every element of the product was addressed.

I had ended the teardown with a promise that I’d continue experimenting with the tiny salvaged UPS, but even if I hadn’t, with so much feedback it seemed revisiting the subject was all but a necessity. It this little UPS really viable? Is it too dangerous to safely implement in your project? Will the thing just blow up?

So with your comments as a guide, and free of the somewhat restrictive teardown format, I set out to conduct a more thorough investigation of this little circuit that caused so much debate last month. It’s not all good news, but it’s not in the trash either. Not yet, anyway.

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It’s Not Morning Until Green O’clock

May 19, 2018 by Kristina Panos 13 Comments

[JohnathonT] has a two-year-old who can’t reliably tell time just yet. Every morning, he gets up before the rooster crows and barges into his parents’ room, ready to face the day.

In an effort to catch a few more Zs, [JohnathonT] built a simple but sanity-saving clock that tells time in a visual, kid-friendly way. Sure, this is a simple build. But if a toddler is part of your reality, who has time to make one from logic gates? The hardware is what you’d expect to see: Arduino Nano, a DS1307 RTC, plus the LEDs and resistors. We think an RGB LED would be a nice way to mix up the standard stoplight hues a bit.

At a glance, little Mr. Rise and Shine can see if it’s time to spread cheer, or if he has to stay in his room and play a bit longer. At 6:00AM, the light powers on and glows red. At 6:50, it turns yellow for 10 minutes. At the first reasonable hour of the day, 7:00AM, it finally turns green. In reading the code, we noticed that it also goes red at 8:00PM for 45 minutes, which tells us it also functions as a go-to-sleep indicator.

When his son is a little older, maybe [JohnathonT] could build him a clock that associates colors with activities.

Snowboard And Skateboard So Lit You Can Wipe Out And Still Look Good

May 18, 2018 by Bob Baddeley 5 Comments

[Nate] has made snowboarding cool with his Bluetooth connected board. Using 202 WS2812 LEDs carefully wrapped around the edge of the board and sealed with a conformal coating, it’s bright and waterproof. It’s controlled with an Arduino Nano and a Bluetooth classic board, as well as a large swappable USB battery bank; he can get roughly four hours of life at full brightness on his toy.

Where it gets even cooler is with a six-axis gyro connected to the Nano, which tracks the board movement, and the lights respond accordingly, creating cool patterns based on his speed, angles, and other factors. The app used to control this intense ice-rider is a custom app written using MIT App Inventor, which has the ability to work with Bluetooth classic as well as BLE. This came in handy when he made the 100-LED skateboard, which is based on a Feather with BLE and a large LiPo battery. The challenging part with the skateboard was making the enclosure rugged enough (yet 3D printed) to withstand terrain that is a lot less fluffy than snow.

The connected skateboard is controlled by his phone and a Feather.

The case is very rugged to protect the electronics.

Inside the very thick enclosure is a LiPo, Adafruit Feather Bluefruit, and MPU6050 accelerometer + gyro

We’ve seen others use flashlights and a professional connected board, but it’s been a few years and we’re due for a refreshing (and nostalgic) look back on the winter.

NeoPixel Game Rewards Button Mashing

May 12, 2018 by Kristina Panos 2 Comments

Who has the fastest thumbs at Maker Faire UK? That’s the question [wellsey1972] sought to answer when he created this simple game using little more than two NeoPixel rings, two chunky arcade buttons, and a Trinket.

The idea is simple: each button push lights up one NeoPixel. The first one to fill up their ring is the winner, and is treated to a ring of flashing green lights. The loser, of course, gets flashing red. Both controllers are hard-wired to a box containing a Trinket, a custom PCB with pull-up resistors, and two sets of solderless terminals. [wellsey1972] smartly re-purposed a cat 5 cable for sleeker wiring.

He has a few ideas for the future, like going wireless, printing smaller controllers, and making winning more difficult via potentiometer. We humbly suggest that the loser be taunted by the cry of a sad tuba. Mash past the break for a brief demo.

If you like lights and simplicity but find this build less than challenging, try building a minimal secret maze game.

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Flashing An LED The Widlar Way

May 11, 2018 by Jenny List 7 Comments

Regular Hackaday readers will be familiar with the work of Boldport’s [Saar Drimer] in creating beauty in printed circuit board design. A recent work of his is the Widlar, a tribute to the legendary integrated circuit designer [Bob Widlar] in the form of a development board for his μA723 voltage regulator chip.

The μA723 is a kit of parts from which almost any regulator configuration can be made, but for [tardate] it represented a challenge. The μA723 is so versatile that what you can create is only limited by the imagination of the builder. Having done the ordinary before, [tardate] looked toward something unconventional.

The result is modest, a simple LED flasher using the error amplifier as a not-very-good op-amp, building an oscillator at a frequency of about 2 Hz. This is pretty neat and if you are used to the NE555 as the universal integrated circuit, perhaps it’s time to set it aside for the obviously far-more-useful μA723.

Here at Hackaday we harbour at least one fan of the μA723, not to mention also of artful PCBs. If the Widlar looks familiar, we featured the switch mode regulator from the μA723 data sheet on it a few months ago.

Disclosure: [Jenny List] wrote the documentation for Boldport’s Widlar kit.

PIC16Maze Upgrades Secret Maze Game

May 9, 2018 by Steven Dufresne 4 Comments

We really like it when a reader is inspired by something they see on Hackaday, build on it, and let us know so we can pass it on. In this case, [Vegipete] made a secret maze game using a minimal number of parts and some neat software trickery.

It’s built around an 8-pin PIC16F18313 microcontroller, uses a joystick for input, and nine WS2812 LEDs to display the player and the surrounding maze walls. His inspiration was [David Johnson-Davies’] minimalist secret maze game built around the 8-pin ATTiny85. In that one, [David] cleverly used charlieplexing to get four pins to control four LEDs and four pushbuttons. [Vegipete’s] use of the WS2812 LEDs allowed him to control the LEDs with just one pin, and also get color while using three pins for the joystick and its button. He may use another pin in the future for sound and vibration.

He goes into some detail on the WS2812 protocol, how communication is done with the LEDs using just one pin and different pulse-lengths to represent 0 and 1. We’ll leave you to see his post for more depth but basically, he introduces a module on the PIC called the Configurable Logic Cell (CLC) which makes this easy and frees up processor cycles for the user’s code to do other things.

His source code is available on request but he does detail a neat software trick he uses for rotating the view. It may be confusing for some but as you move through the maze, your viewpoint rotates so that up is always the direction you’re facing. Luckily, the walls surrounding the user can be represented using 8-bits, four for east, west, north, and south, and four more for the corners. The maze is stored as a bitmap and from it, 8-bit values are extracted for the current position, each bit representing a wall around the position. To rotate the walls to match the user’s current orientation, the bits are simply shifted as needed. Then they’re shifted out to set each LED. Check it out in the video below.