Wireless water heater monitor uses whatever was lying around

wireless-water-heater-monitor

[Chris] set out to build a monitoring system for his water heater. It doesn't Tweet or send SMS messages. It simply lights up an LED when the water heater is active. The one thing that complicates the setup is that he didn't want to pull any wire from the garage into the house. What you see above is the wireless setup he used to accomplish this goal. This is an electric water heater, so [Chris] … [Read more...]

EMF oscilloscope probe

OLYMPUS DIGITAL CAMERA

[Tuomas Nylund] wanted a way to visualize the electromagnetic fields (EMF) around him. He figured the oscilloscope was the tool best suited for the task, but he needed a way to pick up the fields and feed them into one of the scope's probes. He ended up building this EFM probe dongle to accomplish the task. He admits that this isn't much more than just an inductor connected to the probe and … [Read more...]

Metal detection using an inductor instead of a clock crystal.

pic-metal-detector

This project from a few years back is an interesting take on a metal detector. Instead of building a detection circuit, [Bruno Gavand] replaced the external clock crystal with an inductor. Here you can see the inductor coil next to the PIC 12F683. You can see two components jumping from one breadboard to the other. These are smoothing capacitors on the inductor lines. The watchdog timer for the … [Read more...]

Barebones PIC RFID tag

barebones-pic-rfid-tag

An inductor and 8-pin microcontroller are all that make up this barebones RFID tag. You might have done a double-take when first seeing the image above. After all, there's nothing hooked up to the power and ground pins on the chip. As [Ramiro Pareja] explains in his post, the power is actually supplied via the I/O pins to which the inductor is soldered. It seems that each I/O pin has a parasite … [Read more...]

Beginner Concepts: A quartet of videos on Inductors

inductor-basics

Inductors can be found in many of the devices you use every day, but if you've been working only with DC in your projects there's a good chance you've never needed to know anything about them. Now's your chance to pick up on the basics with this video tutorial series. [Afroman] put together four short videos that we've embedded after the break. Set aside fifteen minutes to watch them; you'll be … [Read more...]

Making EL wire

[Jeri Ellsworth] adds electroluminescent wire to the list of things she makes. The materials list is incredibly low. The common components are epoxy coated magnet wire for the center conductor and bare wire for the second conductor. The part you don't have on hand is phosphors, although she does link to a source. The bad news: she doesn't show us the build process or share the details about the … [Read more...]

Building a glue stick flashlight

gluestick-flashlight

Building an LED flashlight is simple, right? Take a battery, connect it to an LED by way of a resistor. Alright wise guy, now make one that steps up the voltage for multiple LEDs and don't use a boost-converter IC to do so. [fede.tft] shares a flashlight built inside of a  used glue stick case. It's the perfect size for one AA battery (we're always on the lookout for good battery cases), and a … [Read more...]