We don’t see ourselves wearing these pendants around, but we still enjoyed taking a look at the design. These are just two from a wide range of offerings meant to be worn around and recharged by the sun. But a cloudy day won’t ruing the fun; they can be topped off via USB as well. Parts lists and schematics are included in the assembly Instructables for both the Owl and the Heart.
[Marty] and [Robin], a brother and sister developement/design team, were showing them off at the Sector67 hackerspace in Madison, WI. The single integrated circuit used in both is an OpAmp responsible for managing the blinking. The heart board has a calculator-style solar cell which charges that 0.5F supercap. The Owl has just a 0.022F coin-type capacitor and features a different style of solar harvester. The six components around the cap are each individual solar cells. [Marty] told us that they pump out a ton of juice in direct sunlight, outperforming the calculator-style cell. The opposite is true indoors. But as we’ve seen before, indoor solar harvesting is a tough game.
In industrial applications, controlling relays, servos, solenoids, and the like isn’t just a matter of wiring in an Arduino and plugging in some code. No, for reliable operation you’ll need a PLC – a programmable logic controller – to automate all your hardware. PLCs are usually pretty expensive pieces of hardware, which led [Warwick] to come up with his own. He built two versions, one large and one small that can handle just about any task thrown at them.
Both devices are powered by an ATMEL SAM7S ARM chip running at 48 MHz. The smaller of the two devices has 10 digital inputs, 4 analog inputs, and 8 digital outputs able to sink 200 mA each. The larger PLC has 22 digital ins, 6 analog ins, and 16 digital outputs. Both of these devices have a ton of connectivity with USB, RS-232 and RS-485 ports
Below you can see the large PLC being used as a barcode scanner and as a strange device using compressed air to levitate a ping-pong ball. There’s also a demo of the smaller PLC lighting up some LEDs.
[José Manuel Hermo Barreiro] has spent many many hours crafting these tiny engines from hand. Every single piece is custom made specifically for the engine it is going onto. He has created aircraft engines, car engines, and marine engines that all actually run and are the smallest of their kind in the world.
At one point in this video he stands in a room with several engines lined up, all running smoothly and considers that there are possibly over 15,000 hours of work right there in front of him.
Here’s a video specifically about the 12 cylinder construction.
The most common example of echolocation is in Bats, who emit ultrasonic noise and listen for its return (echo) to judge the location of objects. [Kripthor] doesn’t need to generate the sound himself, he just needs to pick it up at different points. The time difference from the three samples can be used to triangulate coordinates as seen in the image above.
He first tried using a PC sound card to collect the samples. The stereo input only provides two channels so he tinkered around with a 555-based multiplexing circuit to sample from three. The circuit noise created was just too great so he transitioned to using an Arduino. The ADC samples from each microphone via an NPN transistor which is used as a simple amplifier.
Last week we caught wind of a piece from the Today Show that shows very technically minded thieves stealing cars with a small device. Cops don’t know how they’re doing it, and of course the Today show (and the Hackaday comments) were full of speculation. The top three theories for how these thieves are unlocking car doors are jamming a keyless entry’s ‘lock signal’, a radio transmitter to send an ‘unlock’ code, or a small EMP device touched to the passenger side door to make it unlock.
That last theory – using a small EMP device to unlock a car’s door – got the attention of someone who builds mini EMP devices and has used them to get credits on slot machines. He emailed us under a condition of anonymity, but he says it’s highly unlikely a mini EMP device would be able to activate the solenoid on a car door.
This anonymous electromagnetic wizard would like to open up a challenge to Hackaday readers, though: demonstrate a miniature EMP device able to unlock an unmodified car door, and you’ll earn the respect of high voltage tinkerers the world over. If you’re successful you could always sell your device to a few criminal interests, but let’s keep things above board here.