The EnerJar is an open source watt-meter. It measures the amount of energy an appliance is using. You can use it to find out just how much energy it takes to run a microwave, TV or Laptop. Figure out what requires the most energy and give it a break. Or see if you can figure out how to use it in a way that requires a little less energy. Try measuring how much energy your TV uses while it is off. You might be surprised!

Useful tools
* Volt meter
* Ohm meter
* Pliers

Maybe useful/fun tools
* Ammeter

The EnerJar creation can be broken down into a three (or 4) part process.

1. Collect
2. Assemble
3. Calibrate
4. Debug

Part 1 - Collect

Collecting the parts required to build the EnerJar is a fun opportunity to find old appliances and electronics to synthesize into a whole new tool.

Instructions
1. Forage for as many parts as you can from old equipment. Please reuse!
2. Order a (partial) kit from us to supply parts that you could not salvage. see the parts list
3. Gather together all of the tools

Commons parts that you will be able to forage for:
* Potentiometer (knob)
1. Find any knob (ex: volume knob from an old stereo)
2. Make sure that the knob is a potentiometer - it should:
o Have 3 terminals to solder to with wire leads coming from it
note: If it has 6 this is alright too, sometimes the potentiometers are stereo and have two identical components inside
o Turn smoothly, not in small even steps
o Stop after turning about 3/4 of the way around (some differ, but this is pretty standard
3. Make sure that the potentiometer is linear

* LEDs (lights)
1. Locate some electronics that has a sizable LED.
note: The bigger ones tend to be easier to work with.
2. Melt or remove the solder from the LED leads and pull the LED off of the board.
note: Try to keep soldering time to a minimum to avoid damaging the LED. Avoid soldering in one spot for more than 10 seconds at a time.
3. Look on the board where the LED came from; Read the polarity from there if it is labeled
4. If the LED had red and black wires connecting to it, the red is most likely positive, and the black negative.
note: the following connections can be made by hand, holding everything in place, or if the leads are long enough, by wrapping them around each other. The circuit only needs to be connected briefly to determine the polarity of the LED.
5. Connect one end of the LED to the positive terminal of the power supply
6. Connect the other end of the LED to a 470 ohm resistor
7. Connect the other end of the resistor to the negative terminal of the power supply
8. If the LED does not light up at all when these connections are made, try swapping the connections from the LED so that a the lead that was on the battery is now on the resistor and visa versa.
9. If the LED still doesn't light up, ensure that the connections are all being made and then try a different LED

* Jar
1. Find a jar. The opening should be big enough to fit the circuit board which is 2 square inches (not finalized). We used a salsa jar, and it has worked quite well
2. Ensure that you will be able to drill a few holes into the lid without compromising its structural support. You will most likely want to drill at least 3 or 4 1/4" holes into it.
3. Clean the jar and optionally scrape off the paint on the lid and any stickers on the side

* Power cable/extension cord
o Find a sturdy extension cord which is:
+ cuttable - you need to be able to cut this cord.
+ 3 pronged - It should have 3 prongs on both ends. A 2 to 3 prong converter will not work and will be unsafe

Part 2 - Assembly

If you are a DIY beginner, I recommend following through with these instructions. Otherwise, go ahead and build the circuit and then continue on to the calibration page if the display seems to be working or the debugging page if it doesn't (there is a special mode in the PIC to assist with debugging). Please see the hardware page, here,  for more specific information about how this circuit works. It is not required that you understand, but it will most likely make figuring out problems later (and avoiding them to begin with) much easier.

Prerequisites
* Must collect all of the necessary parts and tools
* Must posess rudimentary soldering skills
* Tools:
o Drill or some way to put a few holes into the lid of your jar
o Wire strippers (knife or scissors will do)
o Wire cutters (knife or scissors will do)
o Soldering Iron
o Solder

The Assembly is divided into three stages; Circuit Assembly, Enclosure Assembly & Testing

Part 2 - Step 1 - Circuit Assembly

Background
Now that you have all of the parts and tools together, you can begin construction. This is where you will need to solder. If you do not know how to yet, I recommend find some information on the web about it and then practicing with old parts out of the appliance you salvaged from. Maybe try soldering a few wires together.

Prerequisites

* Must collect all of the necessary parts
* Must posess rudimentary soldering skills (its not hard, there are lots of guides online to get you started)
* Tools:
o Wire strippers (knife or scissors will do)
o Wire cutters (knife or scissors will do)
o Soldering Iron
o Solder

Instructions

1. Place the IC sockets into position on the circuit board
2. Solder the sockets into place.
3. Check that there are no solder bridges connecting neighboring pins
note: the pins are close and the bridges can be small. Unwanted solder bridges could cause hard to detect problems later on)
4. Insert all of the resistors onto the circuit board
5. Solder all of the resistors into place
6. Insert capacitors into place
7. Solder capacitors into place
8. Solder wires connecting to external components (potentiometer, power supply, LEDs and shunt)
9. Go over the circuit board one last time and make sure that all pins are soldered and that there is no extra solder. Remove any excess solder that is making connections that shouldn't be there.
10. Place ICs into their sockets.

note: If you make an error and would like to solder on the circuit board again, remove the ICs so they are not damaged. Soldering near an IC could cause them to be destroyed

Results
At this point you should have a circuit board full of soldered parts. There should be 6 wires hanging from the board.

Next Steps
You are now ready to finish making the last connections and put the entire thing into the jar. Continue on with the enclosure

Part 2 - Step 2 - Enclosure

Assembling the Enclosure

Background
Now we will connect the circuit board you just soldered to the rest of the hardware and to the enclosure, the jar.

Prerequisites

* Circuit board from previous step
* The rest of the parts not already connected to the circuit board
* Necessary tools:
o Drill or some way to put a few holes into the lid of your jar
o Wire strippers (knife or scissors will do)
o Wire cutters (knife or scissors will do)
o Soldering Iron
o Solder

Instructions
Putting it all together

1. Drill a hole for your potentiometer to mount to the lid of the EnerJar
2. Drill two holes for the power cable to fit through
3. Drill a hole for the mounting bolt which connects the lid to the circuit board
4. Mount the bolt to the lid
5. Mount the circuit board to the bolt
6. Mount the potentiometer to the lid
7. Solder the potentiometer to the wires that were soldered into place earlier
8. Solder the power line wires to the wires that were soldered into place earlier
9. Make sure that everything is wired and close the EnerJar

Results
You now have an assembled EnerJar, ready for testing.

Part 2 - Step 3 - Testing

Testing the Assembly

Background
These are the instructions for the first power up and then figuring out what to do next. Every extra detail noticed during this step is vital to the troubleshooting process later. Check for any LEDs turning on, the display flashing a pattern, smoke for a specific component or area, sparks, etc.
If the EnerJar is wired up correctly, the display should briefly flash all 8s with decimal points between each and every LED should briefly light. It should then go into normal power mode where it displays how much power is being used. If nothing is plugged into it, it should read close to zero.

Prerequisites

* Nearby power outlet
* Lamp (nothing fancy or valuable, just in case)
* Must have completed the and steps
* Good luck (these things never work on the first try)

Instructions

warning: You are about to be asked to put main AC power into your EnerJar. Do not touch any exposed metal wiring and make sure there is no exposed metal wiring to touch.
1. note: Upon first power up, watch out for smoke or discoloring parts. If anything is not working the way you expect, unplug it right away in the case that the problem might cause damage if left powered. Watch the EnerJar. Any extra details you remember about what happens will be useful in troubleshooting later
2. Plugin the EnerJar
3. If the LEDs and LED display all flash on and then begin showing numbers, try plugging in something like a lamp and see if you can change the value being displayed
4. If you can change the value being displayed by plugging something into the EnerJar , continue on to the calibration step.
5. If nothing happens at all when you power on, or if you can't change the value being displayed, even with a lamp plugged in, or anything else seems out of place, go to the debugging page.

Results
This process is a checkpoint. You should now know that either something is wrong with your EnerJar, or that everything is working so far.

Next Steps
If everything is working as defined in the instructions, continue on to calibrating your EnerJar

Part 3 - Calibration

Well, we haven't gotten this far yet.  But you should now have a working EnerJar.

If you are having problems, check out our website, enerjar.net.  There you can find all of these instructions and helpful user comments.