Simple Jig Gives Plastic Homes to Orphaned Projects

Look around your bench and chances are pretty good that there’s a PCB or scrap of perfboard or even a breadboard sitting there, wires and LEDs sprouting off it, doing something useful and interesting. Taking it to the next level with a snazzy enclosure just seems too hard sometimes, especially if you don’t have access to a 3D printer or laser cutter. But whipping up plastic enclosures can be quick and easy with this simple acrylic bending outfit.

At its heart [Derek]’s bending rig is not much different from any of the many hot-wire foam cutters we’ve featured. A nichrome …read more http://pje.fyi/Q1xRlz

Paul Jacob Evans

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A Sandbox for DIY Pinball Design

If you’ve always wanted to build your own pinball machine but have no idea where to start, this is the project for you. [Chris] is in the process of building a ¾ size pinball table and is currently in the waiting-for-parts stage. As they arrive, he is testing them in a sandbox he built in an afternoon. Let [Chris]’s proving ground be your quick-start guide to all the ways you could approach the two most important parts of any pin: the flippers and targets.

The field of play is a sturdy piece of particle board, and the cardboard walls are …read more http://pje.fyi/Q0RpLs

Paul Jacob Evans

Circuit Challenge: Two Transistor 3.3V Regulator

[Kevin Darrah] wanted to make a simple 3.3V regulator without using an integrated circuit. He wound up using two common NPN transistors and 4 1K resistors. The circuit isn’t going to beat out a cheap linear regulator IC, but for the low component count, it is actually pretty good.

In all fairness, though, [Kevin] may have two transistors, but he’s only using one of them as a proper transistor. That one is a conventional pass regulator like you might find in any regulator circuit. The other transistor only has two connections. The design reverse biases the base-emitter junction which results …read more http://pje.fyi/PzF0CZ

Paul Jacob Evans

Graphene Biosensors are Extra Quiet

Graphene has attracted enormous interest for electrically detecting chemical and biological materials. However, because the super material doesn’t act like a normal semiconductor, transistors require multiple layers of the material, and that’s bad for 1/f noise especially when the transistors operate at maximum transconductance. Researchers have found a way to operate graphene transistors at a neutral point, significantly reducing 1/f noise while not impacting the sensor’s response.

The team created a proof-of concept sensor that could detect an HIV-related DNA hybridization. The sensor was able to detect very tiny concentrations of the material.

The ion-sensitive field-effect transistors (ISFETs) employed in …read more http://pje.fyi/Pydh18

Paul Jacob Evans

Write Your Own x86 Bootloader

What if you want to make a very lean machine and do without any operating system? Or maybe you want to try to write your own OS, even just for the challenge or fun? Maybe you were reading up on a cool OS architecture and thought to yourself, “I can write that!”. Well, before diving into your code, you’d first have to write something called a bootloader.

A bootloader is code that runs early on in a PC’s, Mac’s, Raspberry Pi’s or microcontroller’s boot sequence, before anything like an operating system is up. Often its job is to set up …read more http://pje.fyi/PxGzp6

Paul Jacob Evans

Hazardous Dollhouse Teaches Fire Safety

Fire safety is drilled into us from a young age. And for good reason, too, because fire hazards are everywhere in the average home. Even a small fire can turn devastatingly dangerous in a matter of minutes. But how do you get kids to really pay attention to scary (and often boring) adult concepts? You can teach a kid to stop, drop, and roll until you’re blue in the face and still might not drive home the importance of fire prevention. Subjects like this call for child-sized visual aids that ignite imaginations.

That’s exactly what firefighters in Poznań, Poland did …read more http://pje.fyi/Px3GN2

Paul Jacob Evans

The Web Clock You Can Control Over a LAN

Not every project is meant to solve a new problem. Some projects can be an extension of an existing solution just to flex the geek muscles. One such project by [limbo] is the Web Clock 2.0 which is an internet-connected clock.

Yes, it uses a WEMOS D1 mini which is equipped with an ESP-12F (ESP8266) and yes, it uses an LCD with an I2C module to interface the two. The system works by connecting to the Google servers to get GMT and then offsets it to calculate the local time. It also has the hourly nagging chime to let you …read more http://pje.fyi/Px11GY

Paul Jacob Evans