DIY Spot Welder Doesn’t Look Like it Will Immediately Kill You

We love hacks that involve mains voltage, but most of the time, for safety’s sake, we secretly hope for that one macabre commenter that details every imaginable way the questionable design choices will result in death. This spot welder may still be dangerous, but it looks like they took some precautions to make it non-lethal, and that counts for a lot.

After their extremely questionable high speed belt sander, this one is, refreshingly, extremely well done. It starts of as a dead standard microwave spot welder build: take apart microwave, try not to die from large capacitor, remove coil, modify coil, and hook up.

After that, it gets to some nice heavy metal music fabrication. Aside from a slightly shocking number of fresh OSHA reportable hand injuries (wear gloves!) the build goes together well. A lot of planning obviously went into it, from the actively cooled transformer to what appears to be a resettable timer circuit for the weld duration, not to mention the way that it just fit together so well at the end. There were some neat ideas as far as home mechanics go that we’ll be using in some of our projects.

In the end, the proof is in the spot-weld. The timer is set, pedal gets pressed down, and when tested, the sheet metal breaks instead of the weld. Video after the break.

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Small Experiments in DIY Home Security

[Dann Albright] writes about some small experiments he’s done in home security.

He starts with the simplest. Which is to purchase an off the shelf web camera, and hook it up to software built to do the task. The first software he uses is the free, iSpy open source software. This adds basic features like motion detection, time stamping, logging, and an interface. He also explores other commercial options.

Next he delves a bit deeper. He starts by making a simple motion detector. When the Arduino detects motion using a PIR sensor it gets a computer to text an alert. After the tutorial begins to veer a little and he adds his WiFi light bulbs to the mix. Now he can send an email and change the color of the lights.

We suppose, that from a security standpoint. It would really freak a burglar out if all the lights turned red when they walked into a room. Either way, there’s definitely a fun weekend project in playing around with all these systems.

DIY Arduino Watch

We first thought [Alexis Ospitia]’s watch was a sports watch made with an Arduino, but it’s actually a sporty watch made with an Arduino. This explains the watch’s strange ability to tell you the current temperature and humidity.

The core of the watch is an Arduino Mini. To make it good for time telling, a real-time clock module was added. A DHT11 monitors the temperature and humidity. A charge circuit and lithium battery provide power. Finally, the watch displays the date, time, and other data with an LCD from a Nokia 5110. We can tell you the last part that’s going to break on this.

Even if you think the watch is a bit chunky, the tutorial is very slick. [Alexis] has taken the trouble to individually draw and describe each portion of the watch’s construction. He explains each pin, what they do, and provides a Fritzing drawing of the wires to the Arduino. The code is provided; to program the watch a USB-to-serial module must be used.

For the housing he made a box from a thin gauge aluminum sheet and attached leather straps to the assembly. The final construction is cool looking in a techno-punk way, and is fairly compact. One might even say sporty.

Add Bluetooth to a Cheap Electronic Lock

[James] works from home. His office is filled with objects that can be described with adjectives such as, “expensive,” and, “breakable.” His home, however, is filled with professional object-breakers known as children. To keep these two worlds from colliding, he installed a keypad lock on his office door. The potential side-effect of accidentally training his children to be master safe-crackers aside, the system seems to work so far.

However, being a hacker, the tedium of entering a passcode soon grew too heavy for him. Refusing to be a techno-peasant, he set out to improve his lock. The first step was to reverse engineer the device. The lock is divided into two halves, one has a keypad and handle, the other actually operates the lock mechanism. They are connected with a few wires. He hooked an oscilloscope to the most likely looking candidates, and looked at the data. It was puzzling at first, until he realized one was a wake-up signal, and the other was the data. He then hooked the wires up to a Bluetooth-enabled Arduino, and pressed buttons until he had all the serial commands the door lock used.

After that it was a software game. He wrote code for his phone and the Arduino to try out different techniques and work out bugs. Once he had that sorted, he polished the app and code until he reached his goal. All of the code is available on his GitHub.

Finally, through his own hands, he elevated himself from techno-peasant to wizard. He need but wave his pocket oracle over the magic box in front of his wizard’s lair, and he will be permitted entry. His wizardly trinkets secure from the resident orcs, until they too begin their study of magic.

Morse Code Waterfall is Cooler Than Your Fifth Grade Science Fair Project

For her science fair project, [David]’s daughter had thoughts about dipping eggs in coffee, or showing how dangerous soda is to the unsuspecting tooth. Boring. Instead she employed her father to help her build a Morse Code waterfall.

A more civilized wea-- tool from a more elegant age. Young Jed--engineer.
A more civilized wea– tool from a more elegant age. Young Jed–Engineer.

[David] worked with his daughter to give her the lego bricks of knowledge needed, but she did the coding, building, and, apparently, wire-wrapping herself. Impressive!

She did the trick with two Arduinos. One controls a relay that dumps a stream of water. The other watches with an optical interrupt made from an infrared emitter and detector pair to get the message.

To send a message, type it in the keyboard. The waterfall will drop spurts of water, and then show the message on the decoder display. Pretty cool. We also liked the pulse length dial. The solution behind the LEDs is pretty clever. Video after the break.

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Home Automation and Monitoring with Edison

[Tyler S.] has built a home automation and monitoring system dubbed ED-E, or Eddie. The name is an amalgam of its two main components, the Edison board from Intel, and some ESP8266 modules.

ED-E’s first job is to monitor the house for extraordinary situations. It does this with a small suite of sensors. It can detect flame, sound, gas, air quality, temperature, and humidity. With this array, it’s probably possible to capture every critical failure a house could experience, from burglars to water pipe leaks. It uploads all this data to Intel’s Analytics Cloud where we assume something magical happens to it.

ED-E can also sense the state of other things in the house, such as doors, with remote sensors. The door monitors, for example, are an ESP8266 and a momentary switch in a plastic case with a lithium ion battery. We’re not sure how long they’ll run, but presumably the Analytic Cloud will let us know if the battery is low via the aforementioned magic.

8728871444406519500_smallLastly, ED-E, can turn things in the house on and off. This is accomplished in 100% Hackaday-approved (if not UL-approved) style with a device that appears to be a lamp cable fed into a spray painted Altoids tin.

ED-E wins some style points for its casing. It’s a very well executed hack, and we’d not previously considered just how many awful situations can be detected with off the shelf sensors.

Measuring Parts for Accurate Reverse Engineering

Previous headquarters of Useful Thing Inc.
Previous headquarters of Useful Thing Inc. They made the best widget you could buy in the 80s.

Like most hackers, I’ve run into a part that looks like it might do what I want, but the only documentation came from a company so thoroughly defunct their corporate office is now a nail salon and a Subway.

So, as any hacker who’s wandered through a discount store with a spare twenty, at one point I bought a Chinese caliper. Sure it measures wrong when the battery is low, the temperature has changed, if I’ve held it in my hand too long, the moon is out, etc. but it was only twenty dollars. Either way, how do I get accurate measurements out of it? Well, half-wizardry and telling yourself educated lies.

There are two golden rules to getting accurate measurements by telling lies. It may be obvious to some, but it took me quite a bit of suffering to arrive at them.

  1. Engineers are lazy. So lazy. Most things are going to be even numbers, common fractions, and if possible standard sizes. If sheets and screws come in 2 and 3mm then you bet you’re going to see a lot of 2mm and 3mm features. Also, even though the metric world is supposedly pure, you’re still going to see more 0.25 (1/4) mm measurements than you are .333333 (1/3) mm measurements. Because some small fractions are easier to think about than decimals.
  2. Your eyes lie. If it matters, measure it to be sure.

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