2 Touch Alarm Circuit ver 3.0

Another simple touch alarm that uses 555 timer IC.

schematic diagram

555 IC pinout

Part List:
R1 - 5.6 Mega ohms 1/4W
R2 - 47 kilo ohms 1/4W
R3 - 1 kilo ohms 1/4W
C1 - 22uF electrolytic capacitor rated 16V
LED - red or any LED (see led info to know more)
BUZZER - any 5v to 12v buzzer
555 IC - LM555 or any timer IC

Other versions:
Simple Touch alarm
Touch switch using Transistor
Touch Alarm ver 1.1.0
Touch switch (ON and OFF separated)

4 Roulette Circuit

This project is a simple roulette circuit made from 555 IC and 4017 decade counter. The circuit can be used for decorations and games. When the touch plate is touched, the LED will start to light up one after the other and when finger or hand is remove, the led will stop after few seconds.

Part List:
R1 - 5.6 Mega ohms 1/4W
R2 - 2.2 Mega ohms 1/4W
R3 - 10 kilo ohms 1/4W
R4 - 1.2 kilo ohms 1/4W
R5 - 560 ohms 1/4W
C1 - 2.2uF electrolytic capacitor rated 10V
C2 - 1uF electrolytic capacitor rated 10V
C3 - 100nF
LED (1-10) - red led ( see LED pinout in case you forgot)
Q1 - 9012, BC557, or similar PNP transistor
555 - LM555 or similar timer IC
4017 - 4017b decade counter
BAT - 9v battery
Touch - any conducting plates

Similar circuit:
LED chaser using 4017

4 LED Light Sequencer using 555

Another 555 IC project that will flash LEDs in such a way that light turns on in a sequence. You can use this as an indicator for turning left or right for vehicles and bikes.

light sequencer circuit

light sequence (LED1 to LED5)

Part List:
R1, R2 - 4.7 kilo ohms 1/4W
R3 - 3.9 kilo ohms 1/4W
R4, R10, R11, R12, R13 - 10 kilo ohms 1/4W
R5 -220 ohms 1/4W
R6 - 390 ohms 1/4W
R7, R8 - 500 ohms 1/4W
R9 - 560 ohms 1/4W
Q1, Q2, Q3, Q4, Q5 - 2N2222, 9013, or similar NPN transistor
LED1 to LED5 - red or any LED (see LED pinout in case you forget the pins)
C1, C3 - 220uF electrolytic capacitor rated 16V
C2 - 100nF
D1, D2 - 1N4001 or any similar diode
555 - LM555 or similar timer IC
DC -12V battery

Part List pinout:

2N2222, 9013 pinout

555 IC pinout

Similar Circuits:
LED flasher by 555 - various flasher schematic using 555 IC
LED light chaser - similar to this circuit but 10 LEDs turn on one after the other

1 Mobile Phone Detector

This project is a simple mobile cellphone detector circuit. As the phone receives or sends massage or call, it sends off signal. The emitted signal will be detected by the circuit and will cause the LED to light up and the buzzer to sound. You can use this circuit as decoration to your cellphone or use this as a detector to unauthorized use of cellphone in prohibited area. Any cellphone activities like sending or receiving SMS, sending videos or any form of data transmission can be detected by this simple circuit. R5 and C7 set the duration of the buzz and ON time of the LED for 1 sec (you can modify it using the 555 timer calculator in monostable mode). Click diagram to enlarge.

phone detector circuit

Part List:
R1, R2 - 2.2 Mega ohms 1/4W
R3, R6 - 1.2 kilo ohms 1/4W
R4, R5 - 10 kilo ohms 1/4W
R7 - 100 kilo ohms 1/4W
C1, C2 - 22pF ceramic capacitor
C3, C7 - 47uF electrolytic capacitor rated 16V
C4 - 220nF
C5 - 33pF ceramic capacitor
C6 - 4.7uF electrolytic capacitor rated 16V
C8 - 100nF
ANT -  just a piece of conductor less than 1ft
Q1 - 2N2222 or similar NPN transistor
LED - red led (see LED pinout in case you forgot)
Buz - 12V buzzer
555 - LM555 or similar timer IC
IC - CA3130 or similar
Bat - 9V to 12V battery

Parts pinout: click diagram to enlarge

CA3130 pins

555 pinout

2N2222 pinout

0 Delay Off Circuit

This project is the exact opposite of simple delay switch circuit. It provides about 14 seconds delay after the moment the switch is open. After this delay, the device is off. Use the 555 IC calculator in monostable mode to change this delay ( just replace R2 and C2 only).

555 pins

P-MOS pins

Part List:
R1- 10 kilo ohms 1/4W
R2 - 56 kilo ohms 1/4W
R3 - 2 kilo ohms 1/4W
C1 - 470uF electrolytic capacitor rated 16V
C2 - 220uF electrolytic capacitor rated 16V
C3 - 100nF Mylar or ceramic capacitor
Q1 - IRF9530 or any  P-channel Mosfet (10A current minimum)
555 - LM555 or similar timer IC
Lamp - any 12V bulb up to 100W (you can replace other device)
DC - 12V battery or DC supply (up to 25V DC)

0 Simple Delay On Switch Circuit

The circuit below is a simple delay switch. What it does is it gives a time delay before your circuit to activate or power up. In our circuit below, when S1 is closed, the 555 timer IC will start counting the delay and when it is reached the bulb will turn on. The time delay is controlled by R2 and C2 combination (see 555 timer monostable calculator to solve this delay). The circuit will power up after 14 seconds the moment the switch is on. You can study also the complement (opposite) of this project, the delay off circuit.

delay switch circuit

555 pins

N-Channel Mosfet pins

Part List:
R1- 10 kilo ohms 1/4W
R2 - 56 kilo ohms 1/4W
R3 - 2 kilo ohms 1/4W
C1 - 470uF electrolytic capacitor rated 16V
C2 - 220uF electrolytic capacitor rated 16V
C3 - 100nF Mylar or ceramic capacitor
Q1 - IRF530 or similar N-channel Mosfet
555 - LM555 or similar timer IC
Lamp - any 12V bulb up to 100W (you can replace other device)
DC - 12V battery or DC supply (up to 25V DC)

You can modify the circuit and replace the bulb with any device. You can replace it also with relay to control higher power devices such a motors, and other 110V or 220V AC devices. You can replace also the Q1 with NPN BJT transistors such as 2N3055, TIP41C and others.

6 12V to 3V buck converter

There are many ways of converting 12V to 3V. You can use regulator IC, transistors, zener diodes and many more. The problem of these converters is very low efficiency and most of their power is converted to heat. A dc-dc converter is a need in this case.
The circuit below is a simple buck converter that converts a 12V DC (usually from battery) to 3V DC. The heart of the circuit is the 555 timer IC that controls the Mosfet and the entire circuit. This converter can deliver a current up to 5A at a 3V load. Current can be made even higher if Q1, D1, and L1 are replaced with much higher current capacity.

buck converter diagram

To make the output voltage more regulated, you can add the circuit below across the converter output.

regulator circuit

Part List:
R1 - 5 kilo ohms 1/4W
R2 - 2.7 kilo ohms 1/4W
R3 - 1.2 kilo ohms 1/4W
R4 -  just remove (its a dummy load)
C1, C2 - 100 nano-Farad capacitor
C3 - 2200uF electrolytic capacitor rated 16V
Q1 - IRF9530 or any similar P-channel Mosfet (10A current min)
D1 - SR506 or any diode rated 6A min (SCHOTTKY preferable)
L1 - 1mH Inductor minimum 6A current rating
555 - LM555 IC
Regulator circuit (optional)
      Dz - 1N5223B or 2.7V zener diode min 1/2W
      R - 120 ohms 1W
      Q - 2N3055, TIP41C or similar NPN transistor

555 pins

2N2222 pins

IRF9530 or PMOS pins

9 Muscle Stimulator Circuit

This circuit produces pulses that can stimulate muscle. The signal generator is the 555 timer IC that produces pulse with 73Hz of frequency (Change the frequency by replacing the values of resistor and capacitor using 555 calculator). Unlike other stimulator, this is a simplified one since it uses less parts and no transformer is needed.

muscle stimulator schematic

Part List:

R1, R2 - 2 kilo ohms 1/4W

R3 - 100 kilo ohms potentiometer

R4 - 120 ohms 1/4W

R5 - 56 ohms 1/4W

R6 - 22 kilo ohms 1/4W

C1 - 3.3uF electrolytic capacitor

C2 - 100nF capacitor

C3 - 22nF capacitor

L - 2mH inductor (maximum)

D1, D2 - 1N4007, 1N4004 or similar diode

LED - 3mm or 5mm low power red LED

Q - TIP31C, TIP41C or even 2N2222 NPN transistor

555 IC - CMOS type 555 timer IC (LMC555)

Electrodes - any conducting pads connected to "out" pin

Part List Pinout: Click to enlarge

2N222 pin

555 IC pins

TIP31,41 pins

Circuit Operation:

3V is step up to higher voltage but a very low current. Potentiometer R3 controls the output voltage. LED intensity indicates the output state, normal light when output is high and totally off when output is low. C3 adds more "sting" effect on the circuit, increasing its value increases its sting. Diode D2 protects the transistor from voltage spikes.

Don'ts:

1. Do not use at a very long period.

2. Do not use near your heart or head.

3. Do not place electrodes in cuts, tongue, mouth, and wet body parts.

4. Do not increase the values of C3 and R6, do not remove R6

5.  Do not use this at all! (My advice)

How to use:

Turn on the circuit and adjust the brightness of the LED to zero by adjusting the potentiometer R3. Place the electrodes (out) in your body at least an inch apart. Adjust the potentiometer slowly until you feel the pulses and stop at a level of "sting" you desire.

Note: Circuit is working but use it at your own risk.

0 Laser sound generator

This is a laser sound generator using the versatile 555timer IC.  This circuit emits both sound and light, thus it can be used in toys and other light with sound effects.

Laser sound generator

555 pins

Part List:

R1 - 22 kilo-ohms 1/4W

R2 - 390 ohms 1/4W

C1 - 470nF

C2 - 47uF rated 16V

555 timer IC

Battery - 6V to 12V

Note: The sound is not really a laser sound, as in the movies (in my opinion). I recommend try building it and see for yourself what its sounds like (+_-).

1 Electronic Siren using 555 timer

This one is a simple electronic siren using 555 IC operated in astable mode at around 1400Hz of frequency (see 555 calculator to know how this frequency is obtained). At the start, the capacitor C2 is charged at a rate dependent on the value of C2 and R3. During this charging process, the output frequency of sound in speaker varies until it’s fully charged. Pushing the push button Pb discharges the capacitor C2, thus output sound also changes.

electronic siren schematic

555 pins CLICK TO ENLARGE

Part List:
R1 - 2.2 kilo-ohms 1/4W
R2 - 10 kilo-ohms 1/4W
R3, R4 - 10 kilo-ohms potentiometer
C1 - 47nF (0.047uF) capacitor
C2 - 1000uF/16V electrolytic capacitor
C3 - 2.2uF/16V electrolytic capacitor
Spk - 8 ohms 1/2w speaker
Bat - 6V to 12V battery
Pb - ordinary normally open push button

4 1.5V led using 555 IC

This LED circuit is powered only by 1.5V cell using the 555 IC. The timer IC is operated in astable mode similar to voltage double circuit, where 1.5V is step up to around 2.5V. The circuit frequency is around 60Hz  and consumes very small power thus leaving it on is not a problem.

1.5V led circuit

Part List:

R1- 39 kilo-ohms
R2- 100 kilo-ohms
R3-10 ohms but if no light  or very dim, just short it
C1- 100nF
C2- 10nF
C3- 220uF electrolytic capacitor
C4- 100uF electrolytic capacitor
D1- preferably  schotky diode but ordinary diode like 1N4001 will do
555- use the CMOS type 555
LED- red, yellow and other low power led (do not use white or blue)
1.5V- any 1.5V battery

Note: You can use  555 timer calculator if you plan to change the frequency of the circuit.

0 Voltage Doubler using 555

This is a type of dc-dc converter that doubles the voltage of the source. The circuit is powered by 555 timer IC that operates in astable mode. The output of the timer generates the pulse, and the diode D and capacitor C store the energy and voltage during the first cycle. The total output voltage delivered to the load is equal to the output of the 555 plus the voltage in the capacitor, which is around 2X the source minus drops in diodes .Example is a 6V input can have around 10V to 11V output and 12V input is about 22V output. In short, output voltage is about twice the value of input.

voltage doubler schematic

Part list:
1-555 IC
1-1.2k ohms resistor
1-22k ohms resistor
1-0.01uF capacitor
2-220uF/25V capacitor (C)
2-1N4148 diode (D) or use germanium diode  for better output
6V to 15v battery or dc supply

Note: Limit the output current up to 25mA only for 6V supply and 60mA for 12v supply  to ensure output voltage stability. You can use 555 timer calculator if you decide to change the frequency and values of resistor and capacitor of your timer IC.

7 Fading LED

This a dual fading led using 555 timer IC. When first LED (Red) starts to increase its light intensity, the other LED (Blue) starts  to get dim. See the fading sequence diagram of the two LEDs below to understand how it works.

fading sequence diagram 

schematic diagram

Part list:
1-555 IC
2-150 ohms resistor
1-20k ohms resistor
1-Red LED
1-Green LED (note :Blue in diagram)
1-220uF/16V electrolytic capacitor
1-NPN transistor (2N2222, 9013, other general purpose NPN)
1-PNP transistor (9012, other general purpose PNP)

1-9V battery

0 Rain alarm circuit

Alarm schematic

materials:
555 timer IC
speaker - 8 ohms
10nF capacitor
aluminum foil touch plate (see above diagram)
2.2uF electrolytic capacitor
R1-3.9k ohms
R2-15k ohms
C-22nF or 0.022uF electrolytic capacitor

When it is raining the aluminum plate becomes  wet, at that instant the 555 IC will start to to produces  pulses (around 2kHz) to the speaker as an alarm.
You can visit links about 555 timer basics or 555 timer calculator for more info.

19 LED flasher circuit using 555 IC

This project is a flashing led circuit powered by 555 timer IC.This

flasher circuit is composed of two versions, the simple led flasher 

that uses only two LED, and big flasher that consists 20  LEDs.

Simple LED Flasher circuit is powered from a 6V to 12V

battery and delivers a current of about 20mA to LED. The 

frequency of the flashing on both LED is controlled by 100K

potentiometer connected between the discharge and trigger pin

of 555 timer IC. The rate of flash ranges from 1blink per 2 

seconds up to 10 flashes per sec.

simple LED flasher schematic

Big LED flasher circuit is composed of 20 LEDs and uses transistors

as the driver and amplifier of the pulses generated by the 555 IC. The 

npn  general purpose type (9013, 2N222, etc), so is the pnp transistor

(9012, BC557, etc) If the supply voltage is 6V, R1and R2 =27 ohms 

while R1 and R2 = 200 ohms if supply voltage is 12V.

Big Led Flasher schematic

You can change the frequency of the flashes by changing the values

of resistors and capacitor using the 555 timer calculator.

If you planning to build up to 300 LED per group just replace the part of the schematic above with this. See diagram below. Power supply used is 12V.

Note: The type of LED can be of any color such as red, green, orange, yellow but not blue or white LED.
          Blue or white LED requires much higher forward voltage to light.

7 cellphone call detector using 555 timer

This simple project uses a 555 timer cmos type. It detects an incoming  call from your cellphone by. The output LED will blink when the inductor detects signal from your cellphone. This detected signal is feed through the transistor
an then triggers the 555 timer IC.The voltage output of the timer is then doubled by the 220uF capacitor and
1N4001diode combination.

cellphone call detector schematic

The timer IC used is a CMOS type, inductor is made of  120-150 tuns of #28 magnetic wire wound in a
5cm diameter. All other parts of this project are not critical and can be replaced to its closest value.

10 40W FLUORESCENT INVERTER PROJECT

This 40W fluorescent inverter project is powered by 555 timer IC and use to drive fluorescent tubes, compact fluorescent lamp (CFL) and even defective fluorescent tube.

From a 12V supply voltage, timer IC generates square wave voltage of about 4.8 kHz. The primary winding (16 turns of #22 AWG) will generate current pulses of about 4A, and in return will induce a high voltage at the secondary winding (450 turns of #30 AWG) of the inverter. This voltage is enough to strike the fluorescent tube even if the filament is not heated thus very suitable to tubes with broken filaments (burnt out filaments).

This inverter project is very suitable in lighting defective fluorescent tubes, thus helps in minimizing tubes disposal problems. The inverter also can light two 40W tubes in series.

Transformer Construction:
The core used is a antenna bar or the ferrite rod. First wind 16 turns of #22 AWG magnetic wire, the above its winding, wind the secondary or the high voltage winding using #30AWG magnetic wire.

windings using ferrite rod

Note: The output of the inverter produces very high voltage and can cause electrocution. Avoid touching it.

4 12V to 10V buck converter using 555 timer IC

This  buck converter is driven by 555 timer IC and converts 12V dc from a battery to 10V dc. The 555 IC  (operated in astable mode ) generates pulses of voltages of 83.3% duty cycle. This pulses turns the transitor on and off and drives the inductor L (buck converter circuit), and as a result generates 10V dc output. For this configuration,

Ra =240K

Rb =4.7K

C =10nF

Q = TIP41C or any of the same specs

Cout = 2200uF (higher the better)

You can add 1N4740A zener diode for output stability.

1 12V to 9V buck converter using 555 timer IC

converter schematic

This  buck converter is driven by 555 timer IC and converts 12V dc from a battery to 9V dc. The 555 IC  (operated in astable mode ) generates pulses of voltages of 75% duty cycle. This pulses turns the transistor on and off and drives the inductor L (buck converter circuit), and as a result generates 9V dc output. For this configuration,

Ra =27K

Rb =10K

C =10nF

L = 20 turns of #22AWG in antenna bar

Q = TIP41C or any of the same specs

Cout = 2200uF (higher the better)

You can add 1N4739A zener diode at the output side for better regulation.

3 12V to 6V buck converter using 555 timer IC

This  buck converter is driven by 555 timer IC and converts 12V dc from a battery to 6V dc. The 555 IC  (operated in astable mode ) generates pulses of voltages of 50% duty cycle. This pulses turns the transistor on and off and drives the inductor L (buck converter circuit), and as a result generates 6V dc output. For this configuration,

Ra =18K

Rb =18K

C =10nF

Q = TIP41C or any of the same specs

Cout = 2200uF (higher the better)

L= 40 turns #22AWG magnetic wire on antenna bar

For better regulation, you can add zener diode (1N5233B) across  the output.

converter schematic