Traffic Light Project

This project operates red, amber and green LEDs in the correct sequence for a single UK traffic light. The time taken for the complete red - red & amber - green - amber sequence can be varied from about 7s to about 2½ minutes by adjusting the 1M preset. Some amber LEDs emit light that is almost red so you may prefer to use a yellow LED. The 555 astable circuit provides clock pulses for the 4017 counter which has ten outputs (Q0 to Q9). Each output becomes high in turn as the clock pulses are received. Appropriate outputs are combined with diodes to supply the amber and green LEDs. The red LED is connected to the ÷10 output which is high for the first 5 counts (Q0-Q4 high), this saves using 5 diodes for red and simplifies the circuit.
This project uses a 555 astable circuit to provide the clock pulses for the 4017 counter.

Parts Required

resistors: 470 ×3, 22k, 100k
capacitors: 0.1µF, 1µF 16V radial, 10µF 16V radial
diodes: 1N4148 ×6
LEDs: red, amber (or yellow), green
1M preset, horizontal
555 timer IC, such as NE555
4017 counter IC
DIL sockets for ICs: 8-pin, 16-pin
on/off switch
battery clip for 9V PP3
stripboard: 20 rows × 21 holes

Stripboard Layout

Circuit diagram

Electronics phone locker

Phone locker
Building a electronics phone lock is so easy. Any one can build it their home by the help of few electronics components. The phone locker is very simple to construct and can be housed in a small plastic cabinet of the size of a match box. Only you have to connect it in the phone as shown in the circuit diagram.
PART LIST
PARTS LIST Telephone     -
Resistor     220 K
LED     GREEN
LED     RED
Capacitor     1 400V
Switch     SP

Description
When the handset is removed from cradle of the telephone, one of the LEDs lights up, indicating that the phone is not dead. And on dialling required number, the LEDs start flickering, indicating that the number is being dialled. This way one can detect whether someone is misusing the phone from the wires going outside the house.

Once the ringing tone reaches the caller and the caller lifts his own handset, the other LED lights up indicating that the call is matured. For differentiation, two different coloured LEDs have been used. This happens due to reversal of the polarity of voltage in the exchange wires. When switch is moved to ‘off position, the capacitor is introduced in the circuit. In this position the phone becomes for the outgoing calls but the incoming calls regularly come through the capacitor, i.e. you can listen to the voice of the caller but they cannot listen to your voice. So, to enable the incoming calls, the switch should be moved to ‘on’ position and the conversation made as usual.

In this way you can build the electronics phone lock in your home.

..Read more http://electronicsproject.org/phone-locker/
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pin configuration of PIC16F876A

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Pin description
PIC16F876A has a total of 28 pins. It is most frequently found in a DIP28 type of case but can also be found in SMD case which is smaller from a DIP. DIP is an abbreviation for Dual In Package. SMD is an abbreviation for Surface Mount Devices suggesting that holes for pins to go through when mounting aren't necessary in soldering this type of a component.

There are 28 pins on PIC16F876A. Most of them can be used as an IO pin. Others are already for specific functions. These are the pin functions.
1. MCLR – to reset the PIC
2. RA0 – port A pin 0
3. RA1 – port A pin 1
4. RA2 – port A pin 2
5. RA3 – port A pin 3
6. RA4 – port A pin 4
7. RA5 – port A pin 5
8.

Engineering Ebook , Notes ,Project report

Pages

Proposal traffic light system