HsNet: Node communications for feature-limited microcontrollers

[Diego Spinola] wrote in to tell us about a node communication system he’s been working on called HsNet. The aim is to build a system of nodes that can be made up of small and inexpensive microcontrollers. The problem is that the least expensive controllers often don’t have a hardware UART. HsNet implements the RS485 protocol using a software … Read the rest

Multitool alarm system

Here’s a way to make sure you don’t leave your Leatherman multitool somewhere. It’s an alarm system that will start a timer when the tool is removed from the holster. After five minutes the module beeps to remind you to put the tool back where it belongs. Annoying? Possibly, but if you’re not done with your work just press the … Read the rest

Driving an 8-digit split flap display

[Markus] got his hands on a split-flap display and built a controller for it. These sometimes can be found on really old alarm clocks, but [Markus] was a lucky-duck and managed to acquire this large 8-digit display which previously made its home in a railroad station. They work like a Rolodex, mounting flaps around a cylinder for a full … Read the rest

Halloween props: Dancing spider

[Isaac] grabbed the motor from an old printer and used it to make a spider run up and down the wall for Halloween. A PIC 12F683 uses a MOSFET to drive the motor. The program loop has a little bit of dramatic flare to it, raising the arachnid with a bit of a jerky motion to give it some life, … Read the rest