Power Meter Kit

I wanted to see how much power different devices used and what the power factor was. Power factor is how synchronized the current and voltage are. A power factor of 1 is perfect, close to 0 is really bad. A device that pulls 1 Amp and 60 Watts at 120V will have a power factor of .5, because the real power (Watts) is half the apparent power (VoltAmps).
I have some smart plugs that claim to measure Watts- but actually measure VoltAmps. Sometimes their measurements were 25 times higher than it really was because the power factor was .03. They would say a device used 50 Watts, but was actually only using 2 Watts (and 50 VoltAmps). Other meters such as the KillAWatt 4400 measured things more accurately but only displayed one thing at a time.
I decided to buy a panel mount power meter instead of a self contained one, and add my own case and cord. The one I ordered came quickly through Amazon, and I hoped it would be a quick project. Unfortunately, cutting the opening in the metal case was more difficult than I expected. I used a cordless jigsaw, which is not the most accurate. Eventually, I did get the meter to fit, and then added a 14 gauge cord. For now, I added a colored tape wrap on the case. Maybe I will find some spray paint for metal and redo it.
After I set up the meter, I tried it out on some home electronics.
Laptop- 30 Watts with a power factor of .5
TV- 120 Watts with a power factor greater than .9
Bench supply- 8 Watts with a power factor of .6
1.5 Amp phone charger- 8 Watts with a power factor of .6

This meter can measure up to 100 Amps but the plugs in our house can only supply 15. It can measure up to 260 Volts, but 120 Volts is the highest I can plug it into because of the limits of the US power system.

2-channel computer speaker system (solar power part 4)

I found speakers that attached to the side of an old TV. They could be used with individual stands or bolted to the side of the TV. The amplifier inside the TV failed, but the speakers were fine. They sounded better than my previous computer speakers, and could be powered from my solar power system. So I decided to swap them out, and build a wooden stand to hold them. I used scrap wood from IKEA furniture that matched my desk surface, and old fence boards for the uprights.

 I also mounted a switch and an amplifier on the speaker stand.

The new speakers with stand are better because they take up less desk space, sound better, and use solar power.

Recycled Soap #5

After our annual summer vacation family road trip, I ended up with a whole bunch of tiny hotel bars of soap. I decided to combine them with a few from previous years that I had tinted, to make a larger ball of soap that would be easier to use. I used the same process as the previous batches. I shaved them into curls, chips and powder depending on the properties of each bar of soap. Some were ductile and some were brittle. I used a knife that I sharpened with a sharpening stone I bought on the trip.
I added water to make the bits stick together, shaped it into a ball, and set it aside to dry. I am interested to find out how much weight is lost as the water evaporates. The ball of soap is 7 degrees F below room temperature, which suggests that water is currently evaporating.

Power Supply- Beryllium Oxide Thermal Conductor

I recently visited my Great Uncle Mike, who has an amazing inventory of electronic parts in his workshop. I talked to him about some of my problems with past projects and how I'm still learning about electronics. One of the projects that could be improved is my bench power supply. When I first added the 3.3 volt rail, I used thermally conductive double stick tape to attach the regulator to the heat sink because I didn't know any better. It needs to be electrically isolated because the tab is connected to the output of the regulator instead of connected to ground. He suggested a much better solution- a beryllium oxide ceramic material. BeO is about as thermally conductive as copper, but not electrically conductive. He said that this type of material is not used much in consumer electronics because it is expensive and the dust from it is highly toxic. It might be more commonly used by the military or NASA.