Christmas Ornaments 2016

Griffin made these wooden Christmas ornaments from scrap wood he got from Lowes and Home Depot. He used a pattern for a simple tree, and then cut it out with his scroll saw. He drilled a small hole with the drill press so he could hang them. He added patterns with woodburning. Then he put a small nail through the hole and dipped them in clear coat and then let them dry, except for the green one which Mom brushed with clear coat tinted green with oil paint.

Power Tool Battery Charging Station

I built this power tool battery charging station so I could keep my Craftsman 12 volt drill battery and Worx 20 volt weedeater and switchdriver batteries charged. Mom likes this because it keeps these chargers out of the kitchen. The charging station consists of a short extension cord mounted to the underside of the workbench, a power strip, and a shelf for the Worx 20 volt battery. I used 2 pieces of scrap wood from pallet dividers, screwed to the underside of the main supports of the workbench. The shelf keep the battery off the workbench. The craftsman charger doesn't need a shelf because the charger is mounted to a post.
The Worx battery is 27 watt hours and charges at 14 watts. The Craftsman battery is a much smaller capacity but charges at 45 watts. Since the Worx battery is larger, I think it would work better if it charged with a higher power. It takes four times longer to charge. The only good thing about charging at the lower power is that it might make the battery last longer. Judging by the shape of the Craftsman battery, it appears to contain 3 lithium cells in series. The Worx battery appears to contain ten cells, with five sets in series of two parallel cells.
I like lithium ion cordless drills for driving screws because they are lightweight and have a higher pwm frequency compared to corded ones. NiCad drills have heavy batteries but they seem extremely wimpy.

Homemade Bench Power Supply

This is a benchtop power supply I made from a landscape lighting transformer. It has a bridge rectifier, a large heat sink, and 2 linear voltage regulators. One is for the 9-volt output and one is for the 5-volt output. It has 2 incandescent light bulbs wired in series to reduce current draw. It has a max total DC output of 3.5 Amps. It has max output of 1 amp per regulated rail. All the power consumed by the voltage regulators goes through the heat sink so that I only have to run 2 wires to each. 

This is useful for testing circuits, such as 5-5-5 timer circuits. The 5-volt rail is good for testing circuits that normally use a 9-volt battery so that the components aren't damaged by excessive current. I can charge 9-volt batteries through the 9-volt rail. I use another incandescent light bulb when charging the 9 volt battery to limit the current and indicate when the battery is full. 

9 volt regulator

5 volt regulator

bridge rectifier

I found a datasheet for a 5 volt regulator from MCC,

a 9 volt regulator from KEC Semiconductor,  and a gbu 8K bridge rectifier, on AllDataSheets.com.

Doorknob-based Switch

This circuit that turns a motor on and off is based on an old doorknob from our house. If the doorknob is not turned, the motor doesn't run. Turning the doorknob in one direction or the other completes the circuit and determines which direction the motor spins. This type of switch is a momentary single-pole double throw switch with center off.