Wednesday, February 24, 2010
This is the standard Ramsey TFM3 Tri-Field Meter, with my own custom additions to it. First is an LM317 voltage regulator circuit - I misspoke in the video - in fact it now runs on 9Volts (6 AAA batteries) regulated to about 5.5 Volts for proper power esp. in RF mode which tended to drain the battery too low. Next is an extending 1/4 wave antenna such as found commonly in an AM/FM radio - this was to enhance the RF pickup - which is broadband - as such it now picks up even footsteps across a rug, or you petting your dog or cat, and picks up my FM radio transmitter with no problem at all (which was an issue for some people I noted). And last I added a two-transistor sound generator circuit connected to ground and to resistor R30 which is the common input to the LM3914 IC chip in the unit. This video shows it picking up RF easily (probably my wireless network) and also an example of it picking up some RF when petting the cat. (Electrostatic action gives off RF.) Also shows the Electrostatic still works fine, and though I did not show it here, the Magnetic works fine too. Voltage Regulator: ( www.national.com ) Sound: ( www.instructables.com )
http://www.youtube.com/watch?v=5cG9Sl7Fnr4&hl=en
