I haven't added a shade at this point, but that will hopefully be rectified soon. I think I'll try and find one that is yellow and black or yellow and magenta as these are the official color schemes for radiation postings in the U.S. I've also considered making a stained glass shade in these colors, but that will have to wait for warmer weather. Whichever option I go with will play on the radiation theme.
The green twist is that this project uses almost all reused materials. I only bought a new socket, nuts to hold on the feet, and a new rotary switch.
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Signing UpStep 1Materials
- 1 survey meter ( I used a CDV-715)
- A cord with a plug
- White wire
- Black Wire
- A rotary switch (On/off not reostat)
- Wire nuts
- Electrical tape
- Feet (4)
- Nuts (4)
- Lock nuts (4)
- Tubing with lock washers and nuts
- Lamp socket
- Hot glue
Optional materials for LED illumination of the dial:
- LED
- Wires
- Batteries (3 volts in total)
- Scrap metal (I used a penny)
- Plastic container (I used a pill bottle)
- 2 rubber bands (Not pictured)
- A rotary switch (On/off not reostat)
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This is what I did to do it.
I wired in the lamp as per normal for 240v (im in the UK) but i used a 1megaohm rotary switch to turn it on and off using the original range knob.
I also ran off the 240v side a 240v - 12v transformer that i robbed out of an old aquarium pump or something. i opened the unit up and soldered the 240v main feed onto the input side of the transformer. this gave me 12v out the other side.
off of this 12v supply i now wired in a 560k resistor (i think - its covered by heat shrink now) followed by an LED - this illuminated the dial.
Also off of this 12v side I wired in a variable trimpot , sorry i just experimented and found one that worked out of my box of bits) that dropped the voltage and meant i could adjust the needle to fall where i wanted. i just set it to around 3.5r/hr.
to power the meter i simply wired positive up to the +ve side and negative to the -ve side. 12v was to much and pegged it out right off the dial so hence i used a pot.
By doing all this i can switch the lamp on with the original range switch, which turns on the bulb, lights up the LED dial and moves the needle up the scale.
With hindsight i would prob use a few LEDs as the dial isnt that bright, but other than that im happy.
Here is a really crud wiring diagram to explain it, dont flame me as i have no electronics background i just fiddle and made this diagram purely to illustrate this point. If its wrong or i have badly mucked up please tell me!!
i have labelled it as i wasnt sure of all the symbols....
see attached, and also this photo on flickr which illustrates the dial
http://www.flickr.com/photos/flat4/5955640823/in/photostream/
http://www.usps.com/prices/first-class-mail-prices.htm