Why Have Only One Radio, When You Can Have Two?

July 28, 2018 by Jenny List 4 Comments

There are a multitude of radio shields for the Arduino and similar platforms, but they so often only support one protocol, manufacturer, or frequency band. [Jan Gromeš] was vexed by this in a project he saw, so decided to create a shield capable of supporting multiple different types. And because more is so often better, he also gave it space for not one, but two different radio modules. He calls the resulting Swiss Army Knife of Arduino radio shields the Kite, and he’s shared everything needed for one on a hackaday.io page and a GitHub repository.

Supported so far are ESP8266 modules, HC-05 Bluetooth modules, RFM69 FSK/OOK modules, SX127x series LoRa modules including SX1272, SX1276 and SX1278, XBee modules (S2B), and he claims that more are in development. Since some of those operate in very similar frequency bands it would be interesting to note whether any adverse effects come from their use in close proximity. We suspect there won’t be because the protocols involved are designed to be resilient, but there is nothing like a real-world example to prove it.

This project is unique, so we’re struggling to find previous Hackaday features of analogous ones. We have however looked at an overview of choosing the right wireless tech.

Animatronic Puppet Takes Cues From Animation Software

July 27, 2018 by Steven Dufresne 8 Comments

Lip syncing for computer animated characters has long been simplified. You draw a set of lip shapes for vowels and other sounds your character makes and let the computer interpolate how to go from one shape to the next. But with physical, real world puppets, all those movements have to be done manually, frame-by-frame. Or do they?

Stop motion animator and maker/hacker [James Wilkinson] is working on a project involving a real-world furry cat character called Billy Whiskers and decided that Billy’s lips would be moved one frame at a time using servo motors under computer control while [James] moves the rest of the body manually.

He toyed around with a number of approaches for making the lip mechanism before coming up with one that worked the way he wanted. The lips are shaped using guitar wire soldered to other wires going to servos further back in the head. Altogether there are four servos for the lips and one more for the jaw. There isn’t much sideways movement but it does enough and lets the brain fill in the rest.

On the software side, he borrows heavily from the tools used for lip syncing computer-drawn characters. He created virtual versions of the five servo motors in Adobe Animate and manipulates them to define the different lip shapes. Animate then does the interpolation between the different shapes, producing the servo positions needed for each frame. He uses an AS3 script to send those positions off to an Arduino. An Arduino sketch then uses the Firmata library to receive the positions and move the servos. The result is entirely convincing as you can see in the trailer below. We’ve also included a video which summarizes the iterations he went through to get to the finished Billy Whiskers or just check out his detailed website.

[Jame’s] work shows that there many ways to do stop motion animation, perhaps a part of what makes it so much fun. One of those ways is to 3D print a separate object for each character shape. Another is to make paper cutouts and move them around, which is what [Terry Gilliam] did for the Monty Python movies. And then there’s what many of us did when we first got our hands on a camera, move random objects around on our parent’s kitchen table and shoot them one frame at a time.

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Classroom Gadget Turned Arduino Compatible

July 22, 2018 by Tom Nardi 25 Comments

Cheap second-hand hardware is usually a fertile ground for hacking, and by looks of this project, the digital classroom aids that were all the rage a few years back are no exception. [is0-mick] writes in to tell us how he managed to hack one of these devices, a SMART Reponse XE, into an Arduboy compatible game system. As it turns out, this particular gadget is powered by an ATmega128RFA, which is essentially an Arduino-compatible AVR microcontroller with a 2.4GHz RF transceiver tacked on. This makes it an extremely interesting platform for hacking, especially since they are going for as little as $3 USD on eBay.

There’s no USB-Serial converter built into the SMART Response XE, so you’ll need to provide your own external programmer to flash the device. But luckily there’s a labeled ISP connector right on the board which makes it pretty straightforward to get everything wired up.

Of course, getting the hardware working was slightly more complicated than just flashing an Arduino Sketch onto the thing. [is0-mick] has provided his bootloader and modified libraries to get the device’s QWERTY keyboard and ST7586S controlled 384×160 LCD working.

Playing games is fun, but when his friend [en4rab] sent him the SMART Response XE to fiddle with, the goal was actually to turn them into cheap 2.4 GHz analyzers similar to what was done with the IM-ME. It seems they’re well on their way, and [is0-mick] invites anyone who might be interested in filling in some of the blanks on the RF side to get involved.

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Old Phone, New Remote Switch

July 21, 2018 by Jenny List 38 Comments

With mobile phones now ubiquitous for the masses in much of the world for over two decades, something a lot of readers will be familiar with is a drawer full of their past devices. Alongside the older smartphone you’ll have a couple of feature phones, and probably at the bottom a Nokia candybar or a Motorola flip phone. There have been various attempts over the years to make use of the computing power the more recent ones contain through using their smartphone operating systems, but the older devices remain relatively useless.

[Vishwasnavada] has a neat plan though, using an ancient phone as a remote trigger device, by interfacing it with an Arduino. There are many ways this could be achieved depending on the model of the phone in question, but one thing common to nearly all devices is a vibration motor. Removing the motor and taking its power line to a GPIO allows the Arduino to sense when the phone is ringing. The idea then is that a call can be placed to the phone which is not picked up, but because it triggers the vibration motor it can be used to make the microcontroller do something remotely. A hack with limited capabilities then, but one that is cheap and simple, uses a recycled device, and should work almost anywhere populated on the planet given the global reach of 2G networks.

This isn’t the first respin of a classic Nokia we’ve brought you, they will also talk data.

Digital Attenuator Goes From Manual To Arduino Control

July 21, 2018 by Dan Maloney 6 Comments

[Kerry Wong] comes across the coolest hardware, and always manages to do something interesting with it. His widget du jour is an old demo board for a digital RF attenuator chip, which can pad a signal in discrete steps according to the settings of some DIP switches. [Kerry]’s goal: forget the finger switch-flipping and bring the attenuator under Arduino control.

As usual with his videos, [Kerry] gives us a great rundown on the theory behind the hardware he’s working with. The chip in question is an interesting beast, an HMC624LP4E from Hittite, a company that was rolled into Analog Devices in 2014. The now-obsolete device is a monolithic microwave integrated circuit (MMIC) built on a gallium arsenide substrate rather than silicon, and attenuates DC to 6-GHz signals in 64 steps down to -31.5 dBm. After a functional check of the board using the DIP switches, he whipped up a quick Arduino project to control the chip with its built-in serial interface. It’s just a prototype for now, but spinning the encoder is a lot handier than flipping switches, and once this is boxed up it’ll make a great addition to [Kerry]’s RF bench.

If this video puts you in an RF state of mind, check out some of [Kerry]’s other videos, like this one about temperature-compensated crystal oscillators, or the mysteries of microwave electronics.

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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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Energy Harvesting Design Doesn’t Need Sleep

July 19, 2018 by Donald Papp 10 Comments

Every scrap of power is precious when it comes to power harvesting, and working with such designs usually means getting cozy with a microcontroller’s low-power tricks and sleep modes. But in the case of the Ultra Low Power Energy Harvester design by [bobricius], the attached microcontroller doesn’t need to worry about managing power at all — as long as it can finish its job fast enough.

The idea is to use solar energy to fill a capacitor, then turn on the microcontroller and let it run normally until the power runs out. As a result, a microcontroller may only have a runtime in the range of dozens of microseconds, but that’s just fine if it’s enough time to, for example, read a sensor and transmit a packet. In early tests, [bobricius] was able to reliably transmit a 16-bit value wirelessly every 30 minutes using a small array of photodiodes as the power supply. That’s the other interesting thing; [bobricius] uses an array of BPW34 photodiodes to gather solar power. The datasheet describes them as silicon photodiodes, but they can be effectively used as tiny plastic-enclosed solar cells. They are readily available and can be arranged in a variety of configurations, while also being fairly durable.

Charging a capacitor then running a load for a short amount of time is one of the simplest ways to manage solar energy, and it requires no unusual components or fancy charge controllers. As long as the load doesn’t mind a short runtime, it can be an effective way to turn even indoor light into a figuratively free power source.