What do you get if you cross a software defined radio (SDR) and an iconic children’s drawing toy that we are sure is a trademarked name? If you are [devnulling], you wind up with the Etch-A-SDR. The box uses an Odroid C1, a Teensy, and the ubiquitous RTL-SDR.

The knobs work well as control knobs (as you can see in the video below). When you are bored listening to the radio, you can reset the box and go into Etch-a… um, drawing mode. The knobs work like you’d expect and you can even erase the screen with a vigorous shake.

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Resistance is… There’s an Augmented Reality App for That!

Like many engineers of a certain age I learned the resistor color code using a mnemonic device that is so politically incorrect, only Tosh might venture to utter it in public today. When teaching kids, I have to resort to the old Radio Shack standby: Big Boys Race Our Young Girls But Violet Generally Wins. Doesn’t really roll off the tongue or beg to be remembered. Maybe: Bad Beer Rots Our Young Guts But Vodka Goes Well. But again, when teaching kids that’s probably not ideal either.

Maybe you can forget all those old memory crutches. For one thing, the world’s going surface mount and color coded resistors are becoming a thing of the past. However, if you really need to read the color code, there’s at least three apps on the Google Play Store that try to do the job. The latest one is ScanR, although there is also Resistor Scanner and Resistor Scan. If you use an iPhone, you might try this app, although not being an Apple guy, I can’t give you my feedback on that one.

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Want a low-cost ARM platform? Grab a Prepaid Android Phone!

What would you pay for a 1.2Ghz dual-core ARM computer with 1GB RAM, 4GB onboard flash, 800×600 display, and 5 megapixel camera? Did we mention it also has WiFi, Bluetooth, and is a low power design, including a lithium battery which will run it for hours? Does $15 sound low enough? That’s what you can pay these days for an Android cell phone. The relentless march of economies of scale has finally given us cheap phones with great specs. These are prepaid “burner” phones, sold by carriers as a loss leader. Costs are recouped in the cellular plan, but that only happens if the buyer activates said plan. Unlike regular cell phones, you aren’t bound by a contract to activate the phone. That means you get all those features for $15-$20, depending on where you buy it.

android-logo-transparent-backgroundThe specs I’m quoting come from the LG Optimus Exceed 2, which is currently available from Amazon in the USA for $20. The same package has been available for as little as $10 from retail stores in recent weeks. The Exceed 2 is just one of several low-cost Android prepaid phones on the market now, and undoubtedly the list will change. How to keep up with the current deals? We found an unlikely place. Perk farmers. Perk is one of those “We pay you to watch advertisements” companies. We’re sure some people actually watch the ads, but most set up “farms” of drone phones which churn through the videos. The drones earn the farmer points which can be converted to cash. How does this all help us? In order to handle streaming video, Perk farmers want the most powerful phones they can get for the lowest investment. Subreddits like /r/perktv have weekly “best deals” posts covering prepaid phones. There are also tutorials on rooting and debloating current popular phones like the Whirl 2 and the Exceed 2.

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Hack Puts Aging Sprinkler System Online

Water conservation is on a lot of people’s mind, and with an older sprinkler system one may not have the finest control of when and where the lawn is getting its water. Faced with such a system [Felix] decided to hack into his, adding better computerized scheduling, and internet remote control.

The brains of the operation is handled by a Moteino, which is a Arduino compatible micro controller board with WiFi on board. In order to interface with the sprinkler system, an interface PCB is made. The interface has an on board buck power supply to regulate the 24 volt AC power of the sprinkler down to 5 volt DC for the micro and the 74HC595 shift registers.

The output from the shift registers connects to a pin header where the stock computer normally would have plugged in. With a little software and a phone app, the new micro-controller takes over the sprinkler’s TRIAC’s turning on and off zones with a push of the thumb.

Join us after the break for a quick demonstration video.

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Hand Controlled Robot uses Accelerometer

What do orchestra conductors, wizards, and Leap controller users have in common? They all control things by just waving their hands. [Saddam] must have wanted the same effect, so he created a robot that he controls over wireless using hand gestures.

An accelerometer reads hand motions and sends them via an RF module to an Arduino. This is a bit of a trick, because the device produces an analog value and [Saddam] uses some comparators to digitize the signal for the RF transmitter. There is no Arduino or other CPU on the transmit side (other than whatever is in the RF module).

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Lego Exoskeleton Controls Pacific Rim Robot

As hilariously outrageous as Pacific Rim was, it was still an awesome concept. Giant robot battle suits, duking it out with the aliens. Well, it looks as if it wasn’t quite as far-fetched as we first imagined. Maker [Danny Benedettelli] just released a video of his very own Lego exoskeleton suit that when worn can be used to control a desktop size Cyclops robot. You might remember [Danny] as the author of The Lego Mindstorms EV3 Library,

The Cyclops robot (also his design) was originally built four years ago using Lego Mindstorms NXT system with an Android phone running a custom app. Cyclops has been upgraded a bit for this demonstration. Now it communicates over Bluetooth with an Arduino to [Danny’s] telemetry suit.

Relatively speaking, the system is pretty simple. The Lego exoskeleton has potentiometers on each joint, which map to a degree of freedom for the robot. When one potentiometer spins, the associated robot joint mimics it. Simple, right?

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NES Reborn as Nexus Player and NES

Anyone who has a Raspberry Pi and an old Nintendo has had the same thought. “Maybe I could shove the Pi in here?” This ran through [Adam’s] head, but instead of doing the same old Raspberry Pi build he decided to put a Nexus Player inside of this old video game console, with great success. Not only does it bring the power of a modern media player, it still works as an NES.

If you haven’t seen the Nexus Player yet, it’s Google’s venture into the low-cost home media center craze. It has some of the same features of the original Chromecast, but runs Android and is generally much more powerful. Knowing this, [Adam] realized it would surpass the capabilities of the Pi and would even be able to run NES emulators.

[Adam] went a little beyond a simple case mod. He used a custom PCB and an Arduino Pro Micro to interface the original controllers to the Nexus Player. 3D printed brackets make sure everything fits inside the NES case perfectly, rather than using zip ties and hot glue. He then details how to install all of the peripherals and how to set up the Player to run your favorite game ROMs. The end result is exceptionally professional, and brings to mind some other classic case mods we’ve seen before.