Knock lock with logic chips

[Eric] needed a project for his digital logic design class, and decided on a lock that open in response to a specific pattern of knocks. This is a fairly common project that we’ve seen a few builds with ‘knock locks,’ but this one doesn’t use a microcontroller. Instead, it uses individual logic chips.

The lock senses the knocks with … Read the rest

Hunting down farmyard pests with technology

hunting_with_a_camcorder_night_vision_scope

[Snypercat] makes no bones about the fact that she despises rats, and does everything in her power to keep them off her farm. We can’t blame her though – they spread disease, eat other animals’ food, and can get your farm shut down if there are too many running about. While most of us might hire an exterminator or set … Read the rest

DIY Electron Accelerator

Reader [Xellers] sent in his newest instructable: DIY Electron Accelerator: A Cathode Ray Tube in a Wine Bottle. While not exactly what you might think of a cathode ray tube, the basics are in place. A wine bottle is used as a vacuum chamber and a 9kv neon transformer is attached to a stopped in the top. A cathode … Read the rest

A cellphone based Interactive Voice Response System

We’re all familiar with IVRS systems that let you access information using a touch-tone telephone. [Achu Wilso] built his own version which uses a cellphone, microcontroller, and computer.

The cellphone is monitored by an LM324 op-amp with an attached 555 timer chip. When a call comes in the voltage on the headphone output goes high, activating the timer circuit. … Read the rest

Retractable iPad dock for the kitchen

[Evan Flint] and his wife use a lot of online recipes in the kitchen. Rather than printing them out, they bought an iPad as a cooking companion. But in their cramped kitchen he needed to find a place for the high-end hardware that is out-of-the-way yet accessible. Some head scratching and parts bin diving led to this under-cabinet iPod dockRead the rest

Water vortex exhibit repair gives a look at the bearing and gasket design

[Ben Krasnow's] water vortex machine has been an exhibit in the lobby of the San Jose City Hall for quite some time now. Unfortuantely he recently had to perform some repair work on it due to the parts inside the water chamber rusting.

This is the same water vortex that we saw about a year ago. It uses a … Read the rest

Guitar pickup winding workstation

After a bit of inspiration, [Pete] decided to build a solid body electric guitar for himself. Instead of assembling a conglomeration of off-the-shelf parts, he plans on building just about everything from scratch. This includes the guitar pickups, so he built himself a pickup winder that has measures RPM, ETA until done, and auto stop for when the pickup is … Read the rest