The EnerJar - PIC power meter - Electronic Circuits Projects Diagrams Free

futz · 13th February 2008, 04:18 AM

The EnerJar looks like a fun and useful project. It's the winner of the 2008 Greener Gadgets Design Competition. Schematics and source code can be found at the EnerJar site.

blueroomelectronics · 13th February 2008, 04:56 AM

Pretty neat, I've got one of those energy meters I bought from Canadian Tire. Another neat project but too dangerous to build a kit around was the X10 controller (one of Microchips app notes)
I thought about it once, would have called it the Python. Fun part would be the high speed ICD isolation.

http://www.codinghorror.com/blog/archives/000353.html

Oznog · 13th February 2008, 06:56 AM

Kill-A-Watt is truly a great toy.

The EnerJar's missing detail is the power supply. Really you need a transformer which defeats the cheapness factor. There are some other ways to do it though. What most people think is to use a resistor off the main line to feed a cap and zener but the power dissipated in the resistor is silly. Even at 30mA to drive the LED display and PIC and that's like 3.5W.

Displaying the phase, power factor, and line freq is really nice.
Harmonic content is even nicer!

One thing to remember is the ground isn't ground, it's AC neutral. As such if you want to hook it up through a serial port to the computer or whatever then you need an optoisolator or something.

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Similar Threads
Thread	Thread Starter	Forum	Replies	Latest
Strange behavior when PIC is on seprate power supply	Krumlink	Micro Controllers	1	31st January 2008 12:11 AM
Any ham radio folks here willing to humor some dumb questions?	Andy1845c	Chit-Chat	17	5th January 2008 07:41 PM
PIC power on problems....	SnM	Micro Controllers	5	17th November 2007 10:39 PM
Measuring current with a common ground panel meter?	Revolvr	Electronic Projects Design/Ideas/Reviews	8	1st January 2007 06:39 PM
[help] Power consumption issue on bullet counter project *	Lanzer	Electronic Projects Design/Ideas/Reviews	13	26th August 2005 06:06 AM

13th February 2008, 04:18 AM	(permalink)
futz	The EnerJar - PIC power meter The EnerJar looks like a fun and useful project. It's the winner of the 2008 Greener Gadgets Design Competition. Schematics and source code can be found at the EnerJar site. __________________ ========================= Futz's Microcontrollers & Robotics =========================

13th February 2008, 04:56 AM	(permalink)
blueroomelectronics	Pretty neat, I've got one of those energy meters I bought from Canadian Tire. Another neat project but too dangerous to build a kit around was the X10 controller (one of Microchips app notes) I thought about it once, would have called it the Python. Fun part would be the high speed ICD isolation. http://www.codinghorror.com/blog/archives/000353.html __________________ Bill Smart Kits build Smart People http://www.blueroomelectronics.com Last edited by blueroomelectronics; 13th February 2008 at 04:58 AM.

13th February 2008, 06:56 AM	(permalink)
Oznog	Kill-A-Watt is truly a great toy. The EnerJar's missing detail is the power supply. Really you need a transformer which defeats the cheapness factor. There are some other ways to do it though. What most people think is to use a resistor off the main line to feed a cap and zener but the power dissipated in the resistor is silly. Even at 30mA to drive the LED display and PIC and that's like 3.5W. Displaying the phase, power factor, and line freq is really nice. Harmonic content is even nicer! One thing to remember is the ground isn't ground, it's AC neutral. As such if you want to hook it up through a serial port to the computer or whatever then you need an optoisolator or something. __________________ I thought what I'd do was I'd pretend I was one of those deaf-mutes.