12V Corrosion Checker

When testing anything electrical in a car (or boat), you need to test everything under load.That simply means that if a connection is loose or a wire is nearly corroded though, it will read a solid 12 volts until you try to pass some current through it.

This projects makes it simple load 100 ohms onto anything reading 12 volts.  If the voltage reading changes when you switch this device on, you have something else causing a resistance.

ZAGG invisibleSHIELDs + Xacto = Happy Instruments

Happy New Year!

I've installed invisibleSHIELDs on my cell phones and the stuff works great. Even keys rubbing against the glass don't cause a problem.  I was excited to find out that they have then specifically for Fluke 80 series and the Fluke 189.  So I ended up buying a couple but at $15 each. That seemed a little high for a small piece of plastic for the 87s...

DSO Nano AC & DC Coupling Adapter to Shielded Banana

Merry Christmas!

I love the DSO Nano. It is perfect for so many quick uses. You never need an isolation transformer. It works fine in the field because it is so portable. Rechargeable batteries via standard USB. The list goes on and on...

Two issues with the DSO:

1. It does not have AC coupling
2. It does not have 4mm banana sockets

Both of these are solved with a little adapter I built.

AVRISP mkII & Arduino 1.0

There are plenty of reasons why you would want to use your AVRISP programmer to upload sketches to the Arduino board if you own one. In fact, it might be worth spending the $35.

• No bootloader delay when booting.
• Can use the serial port for something else without having to disconnect it to upload.
• Faster.
• Don't have to worry about which bootloader (OPTIBOOT?) and version (today v4.4) to install.
• Can use all of the flash space on the ATmega.

Pill Reminder

Remembering to take a vitamin daily is simple enough. Remember to take a vitamin every three days is nearly impossible (for me). I wanted a solution which will remind me to take the pill and require zero effort. This small project holds two bottles in a fairly nice looking box and flashes red until you take the pill. The act of picking up the bottle (the pill ingestion is assumed) is the entire interface.

Simple Fume Extractor

Some will go so far as to say even a few breaths of the vaporized flux is deadly. Well, it isn't. But, a simple fan to blow away the fumes while soldering is really nice.

Smarter Water Heater Timer

In Los Angeles, we have the "Time-of-Use Program" option from the power company.  From their FAQ:

The prices are based on the time of day when the electricity is actually used, unlike the standard rate when the price for electricity is always the same. 

A higher price is charged during “high peak” hours, which are between 1:00 p.m. and 5:00 p.m., Monday through Friday. The price for electricity during these hours is about twice the cost of the standard rate price.
Surrounding these “high peak” hours, are the “low peak” hours. “Low peak" hours are from 10:00 a.m. to 1:00 p.m. and again from 5:00 p.m. to 8:00 p.m., Monday through Friday. The price for electricity during these hours is slightly higher than the price charged on the standard rate. 

During all of the remaining hours, Monday through Friday, and all weekend long, the price for the electricity you use is about one-half of the price for electricity on the standard rate. These hours are called “base” hours.

 I was lucky in that my house came with a mechanical timer (as part of some Frankenstein solar system). It was easy to set it to turn off the hot water heater from 1 to 5pm. Don't forget about daylight saving time, oh how I hate daylight saving time.

This worked fine except for the most weekends we would forget to reach into the box and turn on the hot water before during laundry or grabbing that all important weekend noon shower. Even the ridiculous note didn't help.

Besides, sticking your finger in there with the 240V always seemed a little sketchy even with that cardboard protecting you.

So, I decided to over-engineer a solution. How about an Arduino powered server following a real time clock?  How about adding a "vacation switch" which will keep the hot water off until it is moved back? How about a "next cycle override" button for those times when money is no object and you need how water now? How about a pulsing blue led to let you know it is thinking?