“That’s Not a Knife…”

[Robin Baumgarten] likes to play dangerously. His latest creation, Knife To Meet You cuts to the quick of cooperative gaming. 3 humans play together against the machine. The object of the game is to hold your button down as long as possible. The game makes this difficult by sweeping a knife across the play field, right at finger level. (Video below.)

Knife to meet you is controlled by a flesh eating Arduino. In addition to reading the controls and driving a servo to move the knife, the Arduino also displays encouraging messages on a 2×20 character LCD.

The idea is to scare people, not to actually slice them up. To this end, the knife is actually a capacitive sensor. When the game detects the knife has contacted soft human flesh, it stops the knife before blood starts flowing. The game indicates a player has been defeated by making several chopping motions toward the loser. If the losing player still has all their digits, a new round begins.

The project was created as part of a 24 hour game jam. The final product is quite nice, built into a wood case that closes up for travel. It even has a carrying handle, so you can bring it to parties and find fresh victims players.

We’re not sure what it is about knives and Arduinos. It was only a few months ago that we saw an Arduino driving a knife wielding tentacle. Could the world’s friendliest microcontroller board be turning on us?
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Hackaday Reviews: Flir One Android

The Flir One thermal camera caused quite a stir when it was launched back in 2014. Both the Flir One and its prime competitor Seek Thermal represented the first “cheap” thermal cameras available to the public. At the heart of the Flir One was the Lepton module, which could be purchased directly from Flir Systems, but only in quantity. [Mike Harrison] jumped on board early, cutting into his Flir One and reverse engineering the Lepton module within, including the SPI data required to talk to it. He even managed to create the world’s smallest thermal imager using a the TFT screen from an Ipod Nano.

flircamA few things have changed since then. You can buy Lepton modules in single quantity at DigiKey now. Flir also introduced a second generation of the Flir One. This device contains an updated version of the Lepton. The new version has a resolution of 160 x 120 pixels, doubled from the original module. There are two flavors: The iOS version with a lightning port, and an Android version with a micro USB connector. I’m an Android user myself, so this review focuses on the Android edition.

The module itself is smaller than I expected. It comes with a snap-on case and a lanyard. While you’ll look a bit like a dork wearing the lanyard, it does come in handy to keep the imager from getting lost or dropped. The Flir One has an internal battery, which of course needs to be topped off before it can be used. Mine charged up in about half an hour.

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Hacklet 104 – Test Equipment Projects

Hardware hackers love their test equipment. There are entire forums dedicated to talking about multimeters, oscilloscopes, signal generators, and other common bench tools. At times it seems we spend more time talking about our tools than actually using them. For some, off the shelf equipment is never quite good enough. These hackers, makers and engineers design and build their own test equipment. This week’s Hacklet is dedicated to some of the best test equipment projects on Hackaday.io!

test-tool-1We start with [Roman] and Handheld Electronic Test And Measurement Lab. [Roman] travels a lot, and often needs to bring a lab’s worth of tools with him. After suffering through several ‘random’ searches, he decided to design a simple tool that would cut down his packing, and not get him strip searched. The handheld lab packs a multimeter, low-frequency oscilloscope, data logger, waveform generator, and several other tools into a small package. The tool can be connected to a PC to display data and update settings. The on-board PIC24 handles all the hard work of taking measurements. Some careful analog design gives this tool 10 megohm of input impedance.

test-2Next up is [Jaromir Sukuba] with 10$ curve tracer. The only way to find out of that a transistor or diode really works as well as the data sheet suggests is to pull out your semiconductor curve tracer. Curve tracers are also perfect for matching transistors for projects like analog synthesizers. [Jaromir] built this quick and dirty tracer over the course of just two evenings. A dsPIC microcontroller runs the show, generating an IV curve by sending pulses through the device under test. Once the curve has been traced, the PIC displays the results on a TFT LCD module. The tracer is a bit limited with a max of 35V at 0.5 amps. Knowing [Jaromir] though, extending the range would only take another evening or two of work.

vlabtoolNext we have [Jithin] with A Versatile Labtool. This tool can do just about everything you could want – all in one box. From oscilloscope to frequency counter to multimeter to current source, and much more. Much like [Roman] up above, [Jithin] chose a Microchip PIC24 MCU as processing heart of his design. The Versatile Labtool connects to a PC via USB. If you’re not close to your PC, an ESP8266 module allows the unit to connect over WiFi. A PC isn’t required though. The on-board OLED is always available for quick measurements.

emtFinally we have [ZaidPirwani] with Engineer’s Multi Tool, his entry in the 2015 Hackaday Prize. [Zaid] started with the popular transistor tester codebase. He ported the code to his own hardware, an Arduino Nano and Nokia LCD. Making the port function required quite a bit more work than [Zaid] expected. He ended up going with a fresh repository and adding a bit of code at a time. Once everything was working, [Zaid] verified that his hardware design operated as expected with a good old-fashioned multimeter. Now that everything is working, [Zaid] is just about out of space on the little ATmega328. Next stop is a Teensy 3.2!


A special thank you goes out to [Jaromir Sukuba] for suggesting test equipment as the theme for this week’s Hacklet. You can find his projects and more on the new test equipment project list! If I missed your project, or if you have a suggestion for a future Hacklet theme, don’t be shy! Drop me a message on Hackaday.io. That’s it for this week’s Hacklet. As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Hoverboards are here – If You’re Crazy Enough to Try

A new video has been stirring questions on the internet this week. It shows a test of the Flyboard Air, a device that is somewhere between a Back to the Future Hoverboard and Green Goblin’s glider. The video depicts pilot [Frank Zapata] taking off, flying around, and landing an a platform not much larger than a milk crate. Plenty of folks are calling the video a fake. After a few back of the napkin calculations though, we’re coming out to say we think it’s real. Details are few and far between, so much of the information in this article is educated guessing based upon the video.

Here’s our hypothesis: Flyboard Air is a jet powered platform with little or no built-in intelligence. Balance, stability and control are all handled by the pilot. A hand controller simply provides throttle to adjust altitude, take off, and land.

jetfeetLet’s start with the jet powered part. During the video, [Frank] looks down at his board and the water below. Between his sneakers we can see two round openings – which look a lot like jet intakes. At the end of the video, [Frank] flies over the camera. stopping the action shows a split second where four exhaust holes are visible on the bottom of the board. These jets look quite a bit like model aircraft jet engines.

We don’t know exactly which engines [Frank] is using, but as an example, the Jet-Cat P 400 RX-G packs 88 lbs of thrust into a shell less than 6 inches in diameter, weighing less than 8 lbs. Four of those engines would provide 352 lbs of thrust. That’s plenty to lift [Frank], the board, and a few gallons of Jet-A strapped to his back.

Why no built-in intelligence? Even the smallest quadcopters have gyros, accellerometers, and PID loops keeping them upright. The problem boils down to the physics of jet engines. Active stability in a fixed pitch rotary blade system requires very fast throttle response. Quadcopters have this with their brushless motors. Turbines however, have throttle lag on the order of seconds. You can’t beat physics. Accelerating 3 or 4 pounds metal from 78,000 RPM (~70% throttle) to 98,000 RPM (~100 % throttle) takes time.

flyboard1Standing on a column of uncontrolled thrust would take quite a bit of skill on the part of the pilot. As it turns out, [Frank] is one of the world’s most experienced thrust riders. His previous invention, the Flyboard uses a personal watercraft to create a column of thrust which the rider stands on. These boards have become tremendously popular at vacation spots in the last few years. There are plenty of videos on [Frank’s] YouTube channel showing the amount of control a skilled ride has over the board. Loops, spins, and other aerobatics look easy.

With that much skill under his belt, [Frank] would have no problem keeping balanced on four jet engines.

Such a skilled rider means that control wouldn’t really be needed on the board. We’re betting that the only electronics are the remote throttle control and the Engine Control Computers (ECU) needed to keep the jets running and synchronized. The two electric ducted fans on the sides of the Flyboard Air appear to be running all the time, only shutting down when [Frank] lands the board.

One final thought – taking off and landing a jet vertically is difficult. Ground effects destabilize the craft. Engines can suck in their own exhaust, stalling them. These are problems faced by the harrier jump jet and the joint strike fighter. [Frank’s ] solution is not never get too close to the ground. If you watch closely, he takes off and lands from a perforated metal platform mounted off the back of a van. The metal doesn’t reflect enough thrust to cause the Flyboard to become unstable or stall.

So is the video real? We think so. This is an amazing achievement for [Frank Zapata]. Is it practical or safe? Heck no! Nor is it cheap – those engines cost €8,845.00 each.  That said, we’d love a chance to ride the Flyboard Air – after a few hours of training on the original Flyboard of course.

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Open Source Robotics With WireBeings

Everyone needs a cute robotic buddy, right? [Matthew Hallberg] created WireBeings, an open source 3D printed robotic platform. Looking like a cross between Wall-E and Danbo, WireBeings is designed around the Arduino platform. We do mean the entire platform. You can fit anything from an Arduino micro to a Mega2560 stacked with 3 shields in its oversized head. There’s plenty of room for breadboards and custom circuits.

WireBeings is designed to be 3D printed. All the non-printable parts are commonly available. Gear motors, wheels, the ubiquitous HC-SR04 ultrasonic sensor, and a few other parts are all that is needed to bring this robot to life. Sketches are downloaded via USB. Once running, WireBeings can communicate via an HC-06 Bluetooth module.  If the Arduino isn’t enough power for whatever project you’re working on, no problem. [Matt] designed WireBeings to carry a smartphone. Just connect the robot and phone via Bluetooth, and let the phone’s processor do all the heavy lifting. What if you don’t have a spare phone? Check our report on hacks using prepaid Android Smartphones.

We could see WireBeings as the centerpiece for a “learn Arduino” class at a hackerspace. Start with the classic blinky sketch on one of the robot’s eyes. Build from there until the students have a fully functioning robot.

There is definitely room for improvement on the WireBeings project. [Matt] made the rookie mistake of going with a single 9-volt battery to power his creation. While a 9V is fine for the Arduino, those motors will quickly drain it. [Matt’s] planning on moving to a LiPo in the future. Why not stop by the project page and give him a hand?

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Hacklet 103 – Piezo Projects

The piezoelectric effect is simple in its rules: Apply mechanical stress to a material and you generate an electric charge. The inverse is also true: Apply a voltage to a material, and it changes shape. This doesn’t work for everything, though. Only certain materials like crystals, some ceramics, and bone have piezoelectric properties. The piezoelectric effect is used quite a bit in electronics, so it’s no surprise that plenty of hacker projects explore this physical phenomena. This week’s Hacklet is all about some of the best projects utilizing the piezoelectric effect on Hackaday.io!

strumWe start with [miro2424] and StrumPad. Strumpad lets you play a MIDI instrument by strumming, just like a guitar. A music keyboard acts as the guitar fretboard here – keys can be pressed to choose notes, but no sound is generated. When the strumpad is strummed, six copper strips act as capacitive sensors. Touching the strips determines which notes will be played. A piezo disc hiding below the circuit board detects how hard the notes have been strummed or tapped. The ATmega328 running the strumpad then passes the velocity and note-on MIDI messages on to a synth.

stmNext up is [Dan Berard] with Scanning Tunneling Microscope. Inspired by a project from [John Alexander], [Dan] created his own Scanning Tunneling Microscope (STM). The key to an instrument like this is precise movement. [Dan] achieves that by using a normal piezo disk. These disks are used as speakers and buzzers in everything from smoke detectors to greeting cards, so they’re common and cheap. [Dan] cut his piezo disk electrode into quadrants. Carefully controlling the voltage applied to the quadrants allows [Dan] to move his STM tip in X, Y, and Z. Incredibly, this microscope is able to create images at the atomic scale.

touchboard[Thatcher Chamberlin] is next with Low-Cost Touchscreen Anywhere. [Thatcher] used a trio of Piezo disks to make any flat surface touch sensitive. The three sensors are placed at 3 corners of a rectangle. Touches with the rectangle will create vibrations in the surface that are transmitted to the piezo sensors. By measuring the vibration time of arrival, it should be possible to determine where the surface was touched. This kind of measurement requires a decent processor, so [Thatcher] is using the ARM Cortex-M0 in NXP’s LPC1114FN28. Initial tests were promising, but we haven’t heard much from [Thatcher] on this project. If you see him online, tell him to hurry up! We’re hoping to turn our parking lot into a giant electronic chess board!

contFinally, we have [Jose Ignacio Romero] with Low Power Continuity Tester. [Jose] used a Piezo element in a slightly more mundane way – as a buzzer. Who needs a whole multimeter when you’re just trying to check continuity on a few circuits? This continuity tester uses a PIC12LF1571 processor to find open and short circuits. The 5 10 bit ADC in the PIC is plenty of resolution for this sort of tester. In fact, [Jose] even included a diode test, which emits a short beep if the leads are placed across a working diode. The PIC processor uses so little power that this tester should run for around 800 hours on a CR2032 watch battery.


If you want to see more piezo projects check out our brand new piezo projects list! If I missed your project, don’t get buzzed! Drop me a message on Hackaday.io, and I’ll add it to the list. That’s it for this week’s Hacklet. As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Hacklet 102 – Laundry Projects

Ah laundry day. The washing machine, the dryer, the ironing, and the folding. No one is a fan of doing laundry, but we (I hope) are all fans of having clean clothing. Hackers, makers, and engineers are always looking for ways to make a tedious task a bit easier, and laundry definitely is one of those tedious tasks. This week we’re checking out some of the best laundry projects on Hackaday.io!

laundrifyWe start with [Professor Fartsparkles] and Laundrify. Anyone who’s shared a washer and dryer with house or apartment mates will tell you how frustrating it can be. You bring your dirty laundry downstairs only to find the machines are in use. Wait too long, and someone has jumped in front of you. Laundrify fixes all that. Using a current sensor, Laundrify can tell if a machine is running. An ESP8266 monitors the current sensor and sends data up to the cloud – or in this case a Raspberry Pi. Users access this laundry as a service system by opening up a webpage on the Pi. The page includes icons showing the current status of each machine. If everything is in use, the users can join a queue to be notified when a machine is free.


borgmachineNext up is [Jose Ignacio Romero] with Borg Washing Machine. [Jose] came upon a washer that mechanically was perfect. Electrically was a different story. The biggest issue was the failing mechanical timer, which kept leaving him with soapy wet clothing. Washing machine timers boil down to mechanically timed multipole switches. They’re also expensive to replace. [Jose] did something better – he built an electronic controller to revitalize his washer. The processor is a PIC16F887. Most of the mains level switching is handled by relays. [Jose] programmed the new system using LDmicro, which is a ladder logic implementation for microcontrollers. For the uninitiated, ladder logic is a programming language often used on industrial Programmable Logic Controller (PLC) systems. The newly dubbed borg machine is now up and running better than ever.



Next we have [Michiel Spithoven] with Hot fill washing machine. In North America, most washing machines connect to hot and cold water supplies. Hot water comes from the home’s water heater. This isn’t the case in The Netherlands, where machines are designed to use electricity to heat cold water. [Michiel] knew his home’s water heater was more efficient than the electric heater built into his machine. [Michiel]  hacked his machine green by building an automated mixing manifold using two solenoid valves and a bit of copper pipe. The valves are controlled by a PIC microprocessor which monitors the temperature of the water entering the machine. The PIC modulates the valves to keep the water at just the right temperature for [Michiel’s] selected cycle. [Michiel] has been tracking the efficiency of the new system, and already has saved him €97!


laundrespFinally we have [Mark Kuhlmann] with LaundrEsp. [Mark’s] washing machine has a nasty habit of going off-balance and shutting down. This leaves him with soggy clothing and lost time re-running the load. [Mark] wanted to fix the problem without directly modifying his machine, so he came up with LaundrEsp. When the machine is running normally, a “door locked” light is illuminated on the control panel. As soon as the washer shuts down – due to a normal cycle ending or a fault, the door unlocks and the light goes out. [Mark] taped a CdS light detecting resistor over the light and connected it to an ESP8266. A bit of programming with Thinger.io, and [Mark’s] machine now let’s him know when it needs attention.

If you want to see more laundry projects check out our brand new laundry project list! If I missed your project, don’t take me to the cleaners! Drop me a message on Hackaday.io, and I’ll have your project washed, folded, and added to the list in a jiffy. That’s it for this week’s Hacklet. As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!