ESP8266 Zelda Heart Responds To Tweets

July 25, 2018 by Tom Nardi 3 Comments

It might not be enough to make you the Hero of Time, but this piece of Hylian interactive art would still be a worthy addition to your game room. [Jeremy Cook] writes in to tell us about how he put together this 8-bit style heart display, and goes into enough detail on the hardware and software sides of things that you shouldn’t have any problem adapting his design for your own purposes.

The build is pretty simple overall but it does assume you have a CNC to cut the basic shape out of MDF. You could cut the shape by hand if you had to, but if you don’t have a CNC the next best thing might be to 3D print the case. You’d potentially have to print it in two parts right down the center though, depending on how big your bed is. Whichever way you create the case, you’ll then need to cut the shape out of a piece of acrylic to make the face.

In any event, once the pieces are cut out [Jeremy] adds in a Wemos D1 Mini, a power supply, and some red LED strips. He provides a wiring diagram, but it’s fairly straightforward stuff. With a couple of 2N2222 transistors he controls the LED strips right from the digital pins of the ESP8266.

The software side is setup to be controlled via IFTTT by way of Adafruit.io. When IFTTT sees one of the keywords on Twitter, it passes a message to Adafruit.io which ultimately talks to the ESP8266 and gets the heart going. The software supports three states (on, off, and half) and gives a good example of a basic IoT implementation on the ESP8266 if you’re looking for some inspiration.

This hack seems like it would fit in perfectly with the Zelda home automation project we covered last year.

BlinkBox: Debugging Tool For Addressable LEDs

July 25, 2018 by Steven Dufresne 4 Comments

How often do you find yourself having to pause a project to make a test circuit or write some test code to find the source of a problem? Do enough variations of the same test and you’ll eventually make a dedicated test tool. That’s just what [Devon Bray] found himself doing.

[Devon] does a lot of work with addressable LEDs of different types and after much experience, created the BlinkBox, a dedicated test tool for addressable LEDs. It supports multiple LED chipsets, you can give it a count of the LEDs you want to light up, and you can choose a test animation. It even writes your settings to an EEPROM so you that don’t have to repeat yourself when you next turn it on.

He’s also done a very nice job packaging it all up, creating a 3D printed case, using backlit buttons for working in the dark, and even added a contrast knob for the LCD screen. Kudos to him for all the effort he’s put making this polished. Everything you need to duplicate it is available on his webpage, along with the schematic for the curious. Watch it in action, or just admire his handiwork in the video below.

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Recycle LCDs Into LEDs

July 21, 2018 by Al Williams 12 Comments

We always find it funny when we see ads for modern LED TVs. These TVs don’t use LEDs to show the picture. They are nothing more than LCD screens with LED backlighting instead of cold cathode fluorescent lamps. [Akshaylals] had a few LCD laptop and phone panels that were defunct and decided to recycle them to get to the LEDs within.

Most panels are lit from one or two edges with a bar of LEDs. You only have to peel off some tape and plastic. If you wonder what all those plastic sheets do, see the [Engineer Guy’s] video, below.

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Arduino Powered Arcade Button Lighting Effects

July 20, 2018 by Tom Nardi 4 Comments

As if you already weren’t agonizing over whether or not you should build your own arcade cabinet, add this one to the list of compelling reasons why you should dedicate an unreasonable amount of physical space to playing games you’ve probably already got emulated on your phone. [Rodrigo] writes in to show off his project to add some flair to the lighted buttons on his arcade controller. (Google Translate)

The wiring for this project is about as easy as you’d expect: the buttons connect to the digital inputs on the Arduino, and the LEDs on the digital outputs. When the Arduino code sees the button getting pressed, it brings the corresponding LED pin high and starts a fade out timer using the SoftPWM library by [Brett Hagman].

It’s worth noting that the actual USB interface is being done with a stand-alone controller, so the Arduino here is being used purely to drive the lighting effects. The more critical reader might argue that you could do both with a single microcontroller, but [Rodrigo] was in a classic “Use what you’ve got” situation, and already had a USB controller on hand.

Of course, fancy lit arcade buttons won’t do you much good without something to put them in. Luckily we’ve covered some fantastic looking arcade cabinets to get you inspired.

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Blinging Buttons For Pick And Place

July 14, 2018 by Dan Maloney 7 Comments

With 3D-printing, cheap CNC machines, and the huge variety of hardware available these days, really slick-looking control panels are getting to be commonplace. We’re especially fond of those nice indicators with the chrome bezels, and the matching pushbuttons with LED backlighting; those can really make a statement on a panel.

Sadly for [Proto G], though, the LEDs in his indicator of choice were just boring old one-color units, so he swapped them out and made these addressable RGB indicators. The stock lamps are not cheap units, but they do have a certain look, and they’re big enough to allow room for a little modification. The original guts were removed with a Dremel to make way for a Neopixel board. [Proto G] wanted to bring the board’s pads out to screw terminals, so he had to adapt the 3.0-mm pitch blocks he had on hand to the 2.54-mm pitch on Neopixel board, but that actually came out neater than you’d think. With a little hot glue to stick it all back together, he now has fully-addressable indicators that can be daisy-chained together and only take up a single GPIO pin.

These indicators and the nice looking panel they’re on is part of a delta pick-and-place robot build [Proto G] has been working for a while. He’s had some interesting side projects too, like the clickiest digital clock in the world and easing ESP32 setup for end-users. While we like all his stuff, we can’t wait to write up the finished delta.

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Custom Circuit Makes For Better Battery Level Display

July 13, 2018 by Dan Maloney 10 Comments

Isn’t it always the way? There’s a circuit right out of the textbooks, or even a chip designed to do exactly what you want — almost exactly. It’s 80% perfect for your application, and rather than accept that 20%, you decide to start from scratch and design your own solution.

That’s the position [Great Scott!] found himself in with this custom LED battery level indicator. As the video below unfolds we learn that he didn’t start exactly from scratch, though. His first pass was the entirely sensible use of the LM3914 10-LED bar graph driver chip, a device that’s been running VU meters and the like for the better part of four decades. With an internal ladder of comparators and 1-kilohm resistors, the chip lights up the 10 LEDs according to an input voltage relative to an upper and lower limit set by external resistors. Unfortunately, the fixed internal resistors make that a linear scale, which does not match the discharge curve of the battery pack he’s monitoring. So, taking design elements from the LM3914 datasheet, [Great Scott!] rolled his own six-LED display from LM324 quad-op amps. Rather than a fixed resistance for each stage, trimmers let him tweak the curve to match the battery, and now he knows the remaining battery life with greater confidence.

Perhaps the 18650 battery pack [Great Scott!] is building is for the e-bike he has been working on lately. If it is, we’re glad to see that he spot-welded the terminals, unlike a recent e-bike battery pack build that may have some problems down the road.

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LEDs Make An “Analog” Wristwatch

July 5, 2018 by Lewin Day 6 Comments

If you just came down in the last shower, you’re probably used to living in a world where LEDs are cheap, awesome, and practically everywhere. Spare a thought for those of us who lived before the invention of high brightness LEDs – these things still amaze us! A great example of how far we’ve come is this “analog” watch build by [Kevin], featuring no less than 73 of the critters.

The microcontroller running the watch is an STM32, chosen for its easy programmability. It’s running the LEDs in an emulation of the dial of an analog clock, hence the high part count. Naturally, it’s no simple task to cram 73 LEDs and all the necessary connections into the confines of a watch-sized PCB. [Kevin] goes into great detail about the challenges involved, from routing the traces to a tricky power draw problem caused by some odd blue LEDs.

Watch builds are always fun, and they make great conversation pieces for when you want to amaze strangers with your tales of battles fought in the PCB design suite. Now check out this similar build with an entirely different style.