Micro fm Bug
Download in pdf format

Phone line controllerIt might be “yet another” «device» controller that operates over phone-line, but this one works for sure The task was to build a device that connects to the phone line and has a relay as an output switch. It should also sense if the connected «consumer» is turned-on or off and report [...]

Parts:R1-3-5-8-10=1Kohm C1=2.2uF 63V TR1=10K TrimmerR2-7-11=100Kohm C2=4.7uF 25V [...]

This FM transmitter attaches in series to one of your phone lines. When there is a signal on the line (that is, when you pick up the handset) the circuit will transmit the conversation. In particular it will radiate from the phone line itself. It is a passive device – there is no battery. It [...]

The important part of the circuit is formed of the Colpitts type oscillator. C3,C4,C5,C6,CD1-CD2 and L1 determines the frequency. BF982 and dual gate MOSFET are active parts in oscillator. When the input impedance of the MOSFET gate inputs are high, LC tank is not affected. However transistors force the LC tank and cause phase shift. [...]

R1, R101 56 kOhm C1, C101 47 µF/6,3 V, elektrolyt.R2, R11, R102, R111, R16 12kOhm C2, C102 100 nF, fóliovýR3, R103 22 kOhm [...]

Circuit power supply 5V 5A by 7805+Mj2955
This is circuit 7805+Mj2955 power supply 5V 5A for digital circuit.Q MJ2955 for to increase form IC 7805. Q A16 for overload protect.

This is a classic signal mixer that is used for audio purpose. VR1 & VR2 are inputs audio volume controlers and VR3 is used to control the balance between Input1 and Input2. connect a dynamic microphone to Input1 and a music without vocal to Input2, then adjust the VR1, VR2 and VR3 for obtaining a [...]

AVR Thermometer TCN75This small thermometer board uses the Microchip TCN75 device. It is a cheaper clone of the LM75, it costs about 2,50 Euro. The TCN75 comes in a SO8 packaging. The TCN75 is a serially programmable temperature sensor. It has an output that is programmable as either a simple comparator for thermostat operation or [...]

This RF Amplifier is used for boosting small fm transmiters and bugs. It use two Philips 2N4427 and its power is about 1Watt. At the output you can drive any linear with BGY133 or BLY87 and so on. Its power supply has to give 500mA current at 12 Volts. More voltage can boost the distance [...]