Homemade Metal Detector Kit

This idea is both for indoor and outdoor use, depends on how you could modify or enhance it. The important reason you ought to build this circuit is to learn building non-ic oscillators, this trains you on L, C, R and Transistor Switching. – delabs

Homemade Metal Detector Kit

With a handy metal detector you can check beforehand whether there are metal objects in a wall, ceiling or floor. An LED indicates if a metal object is in the vicinity and keeps your simple home projects, simple and safe.

Homemade Metal Detector Kit

Avoid disaster when drilling at home By Ben Godfrey

Ben Godfrey is an electrical engineering student at the University of California, Davis. Ben has written iPhone applications and is a Ham Radio operator.

See also  – Metal Detector Circuits Problem

Homo sapiens to Homo Ludens

A long, long time ago a bright ape figured out that by climbing down from the trees he could more easily master his life, and that of others……Homo sapiens wanted something else, and better. He started to play. Homo ludens was born!

Homo sapiens to Homo Ludens

  • Homo ludens radiactivus – amateur radio
  • Homo ludens radiohistoricus my antique radio collection
  • Homo ludens electronicus – electronic projects
  • Homo ludens aeromodellisticus – model airplanes

Transformers and coils: This is not a building project, but a short and concise lesson in how to design electromagnetic parts. It’s much simpler than what you may expect!

Thermal design: A short course in keeping electronic parts adequately cool.

From Hobby Hound – DIY Electronics

A 40 meter SSB QRP transceiver

“This transceiver was conceived as a power-efficient, small, lighweight unit to be carried in the backpack, along with antenna and battery, for use during trekking and mountaineering trips. It had to be reasonably rugged and reliable, and perform well. Furthermore, I wanted it to solve all the problems the old DSB transceivers had, such as frequency instability, distorted modulation, lack of sensitivity and selectivity, and others.”

Tweet-a-Watt! A safe and simple wireless power monitor

This is an Embedded Project using a XBee. Makes an Energy/Watt/Power Meter into a Wireless Intelligent Sensor.

These Sensors are Interfaced to a PC using another XBee. The Data Acquired can be Displayed(monitor), Logged (sql/csv) and Analyzed (graphs/reports). Then you can form a set of Green Resolutions and Implement them.

Tweet-a-Watt! A safe and simple wireless power monitor

Tweet-a-Watt! A safe and simple wireless power monitor

Tweet-a-Watt starter pack

Monitor upto 1.5 KW, You have to own a Kill-A-Watt device to Add-On this Kit to Web Enable it. Each plug transmits the power usage at that outlet to a central computer receiver. The receiver can then log, graph and report the data.

Antenna-amplifier with BFT 12 for FM-range

The only way to improve the reception of FM-signals or particularly of stereo FM-signals under disadvantageous receiving conditions is to amplify the antenna signal. This should be made directly at the antenna, since the loss is increased meter by meter of any cable. In most cases higher line attenuations can be expected than usually calculated. Even receivers with an additional noise figure of zero do not show any improvements of the signal-to-noise ratio becomes too low because of a long transmission line. Therefore it is practically useless to require extremely low noise figures only for the receivers.

To avoid interferences of signals received from stations of other bands it is propitious to amplify the FM-band only. The band amplifier shown in Fig. 1.3 is connected directly to the 60 ohm output of the FM-antenna, i. e. it is placed at the top of the antenna pole. The matching is achieved by the input band-pass connected to the base of transistor BFT12, being a typically linear silicon transistor for broadband amplifiers. The output filter matched accordingly to a 60 ohm coaxial line is connected to the collector. The operating voltage of 15 V can be supplied by the coaxial line.

Fig. 1.3

Antenna-amplifier with BFT 12 for FM-range

Technical data:

  • Power gain Gp = 22 db
  • Noise figure F = 3.5-4.0 db or 2.2-2.5 KT0
  • Input and output reflexion coefficient |r1| and |r0| <= 0.3
  • dim(60db) at Vout = 680 mV
  • dim(50db) at Vout = 1000 mV

Optimum operating point of minimum intermodulation

Ic =~ 80 mA Vce =~ 7-7.5 V
Supply voltage 15 V

Coil data:

Vogt coil former, ordering code: Sp 3.5/16.6-2048C
Core: U17

  • L1 : 5 turns Cu 0.6 mm \o
  • L2 : 3 turns Cu 0.6 mm \o
  • L3 : 3+2 turns Cu 0.6 mm \o

Choke Ch1 = Ch2: 20 turns Cu L 0.3 mm \o, cross section of winding = 4 mm

Credits –

Antenna-amplifier with BFT 12 for FM-range
from Design Examples of Semiconductor DevicesSiemens Milestones from 150 years – 1974/75

for Information about these pages and purpose, see About Olden Circuits