arduino

2928 Articles

Arduino Detects Pants On Fire

September 21, 2016 by 34 Comments

Hard as it is to imagine, lie detectors have been sold as children’s toys for a number of years. A simple battery-operated device clipped to your fingers and would show the conductivity of your skin. The concept — which is probably not very reliable — observers that lying causes you to imperceptibly sweat which causes a sudden increase in your skin’s conductivity. These cheap toys would have a meter and you’d note the meter deflection to determine if the subject was lying.

You can debate the amusement value of interrogating your friends, perhaps, but they were pretty common and still exist (including some that shock you if they detect you are lying). Seventeen-year-old [BuildIt] has his own modern take on this classic device using — what else? — an Arduino. You can see a video of the device below.

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Staring At The Sun: Erasing An EPROM

September 14, 2016 by 43 Comments

Flash memory is the king today. Our microcontrollers have it embedded on the die. Phones, tablets, and computers run from flash. If you need re-writable long term storage, flash is the way to go. It hasn’t always been this way though. Only a few years ago EPROM was the only show in town. EPROM typically is burned out-of-circuit in a programming fixture. When the time comes to erase the EPROM, just pop it under an ultraviolet (UV) bulb for 30 minutes, and you’re ready to go again. The EPROM’s quartz window allows UV light to strike the silicon die, erasing the memory.

The problem arises when you want to use an EPROM for long term storage. EPROM erasers weren’t the only way to blank a chip. The sun will do it in a matter of weeks. Even flourescent light will do it — though it could take years.

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Complex, Beautiful Device Is Limited To Text-speak And Cat Pictures (WTF, LOL)

September 13, 2016 by 27 Comments

Beautifully documented, modular, and completely open-source, this split flap display project by [JON-A-TRON] uses 3D printing, laser cutting and engraving, and parts anyone can find online to make a device that looks as sharp as it is brilliantly designed. Also, it appears to be a commentary on our modern culture since this beautifully engineered, highly complex device is limited to communicating via three-letter combos and cat pictures (or cat video, if you hold the button down!) As [JON-A-TRON] puts it, “Why use high-resolution, multi-functional devices when you can get back to your industrial revolution roots?” Video is embedded below.

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Simple Clock From Tiny Chip

September 11, 2016 by 15 Comments

If you haven’t jumped on the ESP8266 bandwagon yet, it might be a good time to get started. If you can program an Arduino you have pretty much all of the skills you’ll need to get an ESP8266 up and running. And, if you need a good idea for a project to build with one of these WiFi miracle chips, look no further than [Ben Buxton]’s dated, but awesome, NTP clock.

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Cheap Toy Airboat Gets A Cheap R/C Upgrade

September 7, 2016 by 15 Comments

[Markus Gritsch] and his son had a fun Sunday putting together a little toy airboat from a kit. They fired it up and it occurred to [Markus] that it was pretty lame. It went forward and sometimes sideward when a stray current influenced its trajectory, but it had no will of its own.

The boat was extracted from water before it could wander off and find itself lost forever. [Markus] did a mental inventory of his hacker bench and decided this was a quickly rectified design shortcoming. He applied a cheap knock-off arduino, equally cheap nRF24L01+ chip of dubious parentage, and their equivalent hobby servo to the problem.

Some quick coding later, assisted by prior work from other RC enthusiasts, the little boat was significantly upgraded. Now the boat could be brought back to shore using any R/C controller that supported the, “Bayang,” protocol. He wouldn’t have to face the future in which he’d have to explain to his son that the boat, like treacherous helium balloons, was just gone. Video after the break.

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Rita’s Dolls Probably Live Better Than You Do

September 6, 2016 by 3 Comments

If it wasn’t for the weird Dutch-Norwegian techno you’d presumably have to listen to forever, [Gianni B.]’s doll house for his daughter, [Rita] makes living in a Barbie World seem like a worthwhile endeavor. True to modern form, it’s got LED lighting. It’s got IoT. It’s got an app and an elevator. It even has a tiny, working, miniature television.

It all started with a Christmas wish. [Rita] could no longer stand to bear the thought of her Barbie dolls living a homeless lifestyle on her floor, begging passing toys for enough monopoly money to buy a sock to sleep under. However, when [Gianni] visited the usual suspects to purchase a dollhouse he found them disappointing and expensive.

So, going with the traditional collaborating-with-Santa ruse, he and his family had the pleasure of collaborating on a dollhouse development project. Each room is lit by four ultra bright LEDs. There is an elevator that’s controlled by an H-bridge module, modified to have electronic braking. [Rita] doesn’t own a Dr. Barbie yet, so safety is paramount.

The brain of the home automation is a PIC micro with a Bluetooth module. He wrote some code for it, available here. He also went an extra step and used MIT’s scratch to make an app interface for the dollhouse. You can see it work in the video after the break. The last little hack was the TV. An old arduino, an SD Card shield, and a tiny 2.4 inch TFT combine to make what’s essentially a tiny digital picture frame.

His daughter’s are overjoyed with the elevation of their doll’s economic class and a proud father even got to show it off at a Maker Faire. Very nice!

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Enjoy The Last Throes Of Summer With A Nice Pool Automation Project

September 5, 2016 by 13 Comments

[Ken Rumer] bought a new house. It came with a troublingly complex pool system. It had solar heating. It had gas heating. Electricity was involved somehow. It had timers and gadgets. Sand could be fed into one end and clean water came out the other. There was even a spa thrown into the mix.

Needless to say, within the first few months of owning their very own chemical plant they ran into some near meltdowns. They managed to heat the pool with 250 dollars of gas in a day. They managed to drain the spa entirely into the pool, but thankfully never managed the reverse. [Ken] knew something had to change. It didn’t hurt that it seemed like a fun challenge.

The first step was to tear out as much of the old control system as could be spared. An old synchronous motor timer’s chlorine rusted guts were ripped out. The solar controler was next to be sent to its final resting place. The manual valves were all replaced with fancy new ones.

Rather than risk his fallible human state draining the pool into the downstairs toilet, he’d add a robot’s cold logical gatekeeping in order to protect house and home. It was a simple matter of involving the usual suspects. Raspberry Pi and Arduino Man collaborated on the controls. Import relay boards danced to their commands. A small suite of sensors lent their aid.

Now as the soon-to-be autumn sun sets, the pool begins to cool and the spa begins to heat automatically. The children are put to bed, tired from a fun day at the pool, and [Ken] gets to lounge in his spa; watching the distant twinkling of lights on his backyard industrial complex.