Spooky Tesla Spirit Radio

Step 1 Parts List And Schematic Diagram

List of Materials

1- Small Jam Jar, (Mason Jar) with large mouth
1- 3 1/4 inch dia Plexiglas (or polycarbonate) cover lid, 1/8 inch thick
1- C1 - 60/160 pf Variable Capacitor (ComtrolAuto #VAR160-1)
1- Extension Shaft and Knob for above (ComtrolAuto #ExtKnob-1)
1- L1 -  680 uh Ferrite Loopstick Antenna (ComtrolAuto #LSA680-1)
1- D1 - Germanium 1N34A Diode (*Allied Stock#: 935-0301) $2.16 ea
1- C2 - .001uf Capacitor (marked 102) (*Allied Stock#: 507-0822) $.21 ea
1- R1 - 47k Resistor (*Allied Stock#: 296-6641) $.05 ea
1- Chassis Banana Jack Red - (*Allied Stock#: 528-0158) $.53 ea
1- Chassis Banana Jack Black - (*Allied Stock#: 528-0159) $.53 ea
2 - (or more for each antenna) Banana Plug (*Allied Stock#: 528-0302) $1.21
2 -3.5 mm Mono Chassis Jack (*Allied Stock#: 932-0260) $1.16
a few inches of 20 gauge hook-up wire
solder
1- Audio Patch Cord, 1/8 inch plug ends

Total Cost less than $30.

Note1: Most of the above crystal radio parts are available in kit #SC-Kit-1 from ComtrolAuto 
Note2:Complete crystal spirit radios that can be adapted are available from EJ Gold at YoyodyneIndustries. 

Note3: For Each Spiral Pancake Antenna,
6 feet of #14 gauge solid copper wire
Banana Plug

Note4: For the Football Style Antenna,
4 feet #10 gauge solid copper wire.
40 feet of #30 gauge coated magnet wire.
Heavy Paper
Scotch Tape
Hot Glue
SuperGlue
Banana Plug

Tools
Needlenose pliers
Wire Cutter
Soldering iron
Computer w/ Audio Hijack audio software (Mac), or equivalent

Crystal radio parts and kits available at http://comtrolauto.com/

Comments

[Hetoumon]

Hi, I dove to find all the components?

[mrfixitrick]

I don't understand.  Can you ask your question in another way?

[msim93]

 Pardon me, for it seems as if I'm asking a silly question.
I dont have the parts yet, but when it says "ground through the phone Plug" does that mean the negative of the computer phone jack?

Is that also where you would ground the C1 middle connection?

Like I said, it may be a silly/stupid question for me to ask. I'm still learning how to read schematics properly, and I just dont want to mess anything up.

[mrfixitrick]

 You got it right on both accounts.

It seems that the negative of the computer phone jack works even better than a ground connection I made to a pipe in the ground.

[brooklynlord]

Is this the right kind of diode?

http://cgi.ebay.ca/1N34A-Germanium-Diode-TV-FM-AM-Radio-Detection-1N34-x10_W0QQitemZ250558717109QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item3a56769cb5

It says 1N34A alright, but is it light-sensing?

[mrfixitrick]

 That is it exactly!

Keep in mind that the diode will only respond to the light from one direction (I'll let you figure out which way ;)
Also, the diode will only respond to A/C light (ordinary light-bulb for example) or DC light (laser, flashlight) that is moving.

Good luck with your experiments!

[brooklynlord]

Uhhh..... when you said one direction you mean.........?

[mrfixitrick]

The diode is directional. If you direct the light toward one end of the diode, you get a response. If you direct the light at the other end, there is no response.

[Zettu]

would a 12pF~180pF variable capacitor work about the same for building this radio you think?  any comment to this question would be greatly appreciated,, :)

[mrfixitrick]

 That variable capacitor should work fine. It is within the recommended range.

[Light_Lab]

Hi, This is really cool - I would like to build one with my son if I can get him interested in something other than computer games.
I notice the circuit from Ant1 to the right is identical to the "crystal" radios I used to build as a kid.
The only thing that doesn't make a lot of sense is R1 the 47K resistor. I imagine this is to provide a load to the diode because of the original hi impedance earphone used in the kit. The input impedance of most computer circuits is lower. You should experiment with this resistor perhaps even leave it out.
The use of a germanium diode is important as it has a forward bias voltage of only 0.3 V (ie nothing happens until you get to 0.3V of signal) silicon diodes need 0.6 V.
I suspect the change in signal from the light is because the threshold voltage of the diode is effected.
Early crystal radios used a natural germanium crystal and a "cats whisker" of very fine wire that was moved around to find a good spot on the crystal.
Another early diode was based on copper oxide; if I remember correctly this only needs 0.2V bias. (I have seen a way of making one somewhere on the net).
Prisoners of war made radios using point contact diodes made out of all sorts of things, even rusty spots on razor blades.
It would be fun to experiment with the diode part of the circuit.

[mrfixitrick]

Thanks for the great comments. I believe you are right about the resistor that it can be eliminated for computer use; One crystal site said it was optional...I'll have to try it.

As far as the light affecting the diode...a DC light needs to be moving across the diode to produce sounds, but stationary AC light will make a tone from it. Perhaps threshold voltage is involved there.

In early wartime, they sometimes used the barbwire fence around a compound for an antenna!