LED Tree Brings Gravity to Christmas

Here’s a fun entry into our coin cell challenge. The power source is the actuating force in [Frank]’s blinky LED Christmas tree, which takes advantage of the physical structure of coin cells and our old pal gravity to roll out some holiday cheer. Talk about forward voltage!

We love the concept, and the circuit couldn’t be more simple. A coin cell is released at the top of the tree and rolls down a series of angled foam board railings covered with 1/4″ copper tape. As the coin cell travels, the negative terminal shimmies along the face of the tree, which …read more http://pje.fyi/Q9l8dJ

Paul Jacob Evans

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Afroman Teaches Intro to Servos, Builds Laser Turret

After a longish hiatus, we were pleased to see a new video from [Afroman], one of the most accessible and well-spoken teachers the internet has to offer. If you’re new to electronics, see the previous sentence and resolve to check out his excellent videos. The new one is all about servos, and it culminates in a simple build that provides a foundation for exploring robotics.

[Afroman] leaves no gear unturned in his tour de servo, which is embedded after the break. He explains the differences between open vs. closed loop motor systems, discusses the different sizes and types of servos …read more http://pje.fyi/Q9HFhL

Paul Jacob Evans

The Smartest Air Freshener In The Room

Many automatic air fresheners are wasteful in that they either ceaselessly spritz the room, and manual ones need to be — well — manually operated. This will not do in an era of smart products, so Instructables user [IgorF2] has put together an air freshener that does more than check if you’re around before freshening things up.

The air freshener uses a NodeMCU LoLin and an MG 995 servomotor, with a NeoPixel ring acting as a status light. Be aware — when the servo is triggered there is a significant spike in current, so be sure you aren’t powering the …read more http://pje.fyi/Q6G6b8

Paul Jacob Evans

The Incredible Shrinking Coin Cell Battery Pack

How’s it going with your project for the coin cell challenge? You can only use a single one, but Hackaday alum [Jeremy S Cook] has a great way to package coin cells into a sleek little power packs whether you need one, two, or even four.

[Jeremy] is building a wireless Wii nunchuk, so he needs a small battery that won’t short out or get punctured in the confines of the controller body. A single coin cell holder is already a bit bulky, and he needs to use two in series. He thought, why not try shrink wrapping them together? …read more http://pje.fyi/Q4qS9b

Paul Jacob Evans

Making an Arduino Shield PCB with Fritzing

[Allan Schwartz] decided to document his experience using Fritzing to design, fabricate, and test a custom Arduino shield PCB, and his step-by-step documentation makes the workflow very clear. Anyone who is curious or has been looking for an opportunity to get started will find [Allan]’s process useful to follow. The PCB in question has two shift registers, eight LEDs, eight buttons, and fits onto an Arduino; it’s just complex enough to demonstrate useful design features and methods while remaining accessible.

[Allan] starts with a basic breadboard design, draws a schematic, prototypes the circuit, then designs the PCB and orders it …read more http://pje.fyi/Q2xzlY

Paul Jacob Evans

Tips For Basic Machining on a Drill Press

It’s safe to say most Hackaday readers would love to have a mill at home, or a nice lathe, but such equipment isn’t always practical for the hobbyist. The expense and amount of room they take up is a hard sell unless you’re building things on them regularly, so we’re often forced to improvise. In his latest video, [Eric Strebel] gives some practical advice on using a standard drill press to perform tasks you would normally need a mill or lathe for; and while his tips probably won’t come as a surprise to the old-hands out there, they might just …read more http://pje.fyi/Q1qM1C

Paul Jacob Evans

Control System Fundamentals by Video

If you’ve had the classic engineering education, you probably have a hazy recollection of someone talking about control theory. If you haven’t, you’ve probably at least heard of PID controllers and open loop vs closed loop control. If you don’t know about control theory or even if you just want a refresher, [Brian Douglas] has an excellent set of nearly 50 video lectures that will give you a great introduction to the topic. You can watch the first lecture, below.

You might think that control systems are only useful in electronics when you are trying to control a process like …read more http://pje.fyi/PwH3dG

Paul Jacob Evans