This project blends a previous project of mine with another Instructible's idea for a blinking LED circuit. Thanks to "YNZE's" project Blinky the LED Pet found here : https://www.instructables.com/id/Blinky-the-LED-pet/ it inspired me to try something different with LEDs. Anyway, the concept behind this project is to simulate the 1970's mood ring idea in a Diesel punk, Dr. Frankenstein kind of way. The device acts as a basic dimmer lamp with the feature of changing internal colors when one holds onto the brass electrodes sticking out of each side. When the electrodes are grasped, the ammeter measures the continuity of the circuit adding to the sensation of the meter actually measuring something within your "mood."
Here is how I built it:
3/4" Oak stained with no less than SIX (6) coats of Minwax Ebony stain, followed by a satin polyurethane finish.
Radiometer from Edmunds Scientific ~$12.00
Ammeter newly purchased from eBay ~$8.00 incl shipping.
Slow changing color LEDs ~$6.00 for 50!!!
The transistors found in the Blinky project ~ $4.00 for 50 (if i remember correctly).
Dimmer switch $5.00
9 vdc transofrmer - free off an old cell phone charger
I built the case from scrap 3/4" oak I had laying around. Oak is a very nice wood that takes stain well but I wanted a really dark black finish to resemble an old medical device look. The open grain of the oak really shows up well when this dark so it all worked out fine without having a "painted" look. I purposely designed the box on the small side as possible so it got to be a bit of a challenge to get it together and route the fine wiring but with some work it turned out. I also used a terminal strip that helps to eliminate wire nut nodes and makes it easier on assembly as well.
Make the elecctrical circuit for the mood analyzer. I followed the basic circuit from the Blinky Pet project however to be able to power more LED lights (12 total), I doubled up on the transistors circuit so the voltages and amps would hold up over the voltage drops of the LEDs. There are 4 transistors feeding 6 LEDs for the front light panel and another 4 transistors to power the 6 LEDs facing the rear of the box.
Next I built two led support panels from plexiglass. The plastic allows for light transmission through the entire enclosure and a convenient way to mount the LEDS via through holes that the led leads go through. Be sure to watch the polarity of the LEDs as I wired these in series. The best way to determine the polarity of the led leads is that the positive leg of an LED comes off the smaller portion of the PN junction (just look into the led). The negative is the larger half.
The internals show the support posts for the radiometer which was epoxied into a PVC electrical conduit coupling and the post for the lamp socket. I then used the post to support the circuit board and light panels.
I then finished wiring up the remaining lights and circuits with hook up wire. Then viola - a mood analyzer will change colors as you make and break the circuits!