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Photo Meter Assesses Ambient Light - 10/15/12 EDN-Design Ideas When most PN-junction diodes are reverse biased, they will produce a small photovoltaic output as the light level is increased. Most PN-junction diodes can be used as photodiodes. While not optimized for this application, they do work. When the diode is reverse biased, it will produce a small photovoltaic output as the light level is increased. LEDs are particularly suited for this task because their housings are transparent Design by Raju Baddi Photo Timer - Time is set by potentiometer R2 which provides a range or 1 sec. To 100 seconds with timing capacitor C1 of 100uF. The output at pin 3 is normally low and the relay is held off. A momentary push on switch S1 energies the relay which is held closed for a time 1.1 X (R1+R2) __ Designed by Ravi Sumithraarachchi
Photoflash Capacitor Charger has Fast Efficient Charging & Low-Battery Drain - DN303 Design Notes__ Linear Technology/Analog Devices
PIC Light Chaser - The circuit this month is a simple 8 light chaser built around a PIC. This will demonstrate how easy it is to program a PIC and to utilize it in a circuit. The circuit works as follows. When power is supplied to the circuit the PIC resets and starts. __ Designed by Randy Linscott
PIC16F84 LED Chaser - There are several projects on this page. Please scroll down to find the LED Chaser. __ Designed by Jason KE4NYV from Roanoke, Virginia
Pocket stroboscope - This circuit is a mini storoscope which you can make so small that it can fit into your pocket. The circuit is not very powerful, but is works out of two small 1.5V batteries for an hour constantly and maximum flash rate. The flash rate is variable from zero to about 10 Hz. Quite nice small device to have with you in parties to gain attention __ Designed by Tomi Engdahl
Police Lights - These two circuits flash the left LEDs 3 times then the right LEDs 3 times, then repeats. The only difference is the choice of chips. __ 555-Timer
Portable Lamp Flasher - Here is a portable, high-power incandescent electric lamp flasher. It is basically a dual flasher (alternating blinker) that can handle two separate 230V AC loads (bulbs L1 and L2) . The circuit is...__ Electronics Projects for You
Portable Signal Wand - Flashing lights have varied applications. For example, travelers can use these as warning beacons on highways to catch the attention of the public in case of an emergency. Described here is...__ Electronics Projects for You
Power 220V Flashing LED - AC mains operated single LED flasher circuit, built using the popular CMOS
timer chip TLC555 is shown below. The whole circuit is powered directly by the grid supply of 230VAC through a capacitive potential divider and associated components. This minuscule Power LED Flashing circuit can be easily fit inside a very small __ Designed by T.K. Hareendran
Power Flasher (PAGE 113) - Suitable for alerting purposes. Drives 12V Car bulbs __ Contact: Flavio Dellepiane, fladello @ tin.it
Power-line outage flashes red alert - 06/13/02 EDN-Design Ideas This design idea expands on a circuit in a previous one to configure a power-outage detector with a flashing alarm (Figure 1, Reference 1]. The circuit plugs into a mains outlet and uses trickle-charged nickel-cadmium batteries. The green-LED monitors the presence of line voltage. The BZV55-C4V3 zener diode, D1 protects the batteries against overvoltage Design by Vasiliy Borodai, Zaporozhje, Ukraine
Programmable LED - Alex Inspired by various LED Throwies, blinking LEDs and similar instructables I wanted to do my version of an LED controlled by a microcontroller. The idea is to make the LED blinking sequence reprogrammable. This reprogramming can be done with __ Designed by Radio LocMan
Programmable LED Flashers - LED goes to steady state after a preset number of flashes; Two simple, wide supply range operating circuits __ Contact: Flavio Dellepiane, fladello @ tin.it
Pulsing Third Brake Light - The schematic consists of two 555 timer/oscillators in a dual timer configuration both setup in astable mode. When power is applied via the brake pedal, the brake light driver Q1 is switched on via the low-output pin 3 of IC2, and timer IC1 begins its timing cycle. With the output on pin 3 going high, inhibiting IC2's pin 2 (trigger) via D2, charge current begins to move through R3, R4 and C2. __ Designed by Tony van Roon VA3AVR
Pulsing third Brake lite for cars - Several years ago these flashers were introduced in the automotive industry as part of the third brake light and contained strobe lights (and strobing continuously for the duration of pressing the break pedal) but got abandoned almost immediately sometime later because of the 'strobe' effect it has on some people. This circuit has become obsolet since much better circuits are available these days without the 'lag' in between brakes caused by R4 and C3. One of the circuits is listed below __ Designed by Tony van Roon VA3AVR
Push-bike Light - Automatic switch-on when it gets dark; 6V or 3V battery operation __ Contact: Flavio Dellepiane, fladello @ tin.it
Quiz - This project can be used for a quiz with up to 4 contestants (or teams) . Each contestant has a trigger push-switch and LED. When a trigger switch is pressed it lights the corresponding LED, sounds the bleeper and prevents the other trigger switches from workingtherefore showing which contestant was the first to press their switch __ Designed by John Hewes
Random' Flasher for 8 LEDs - This project uses a 4026 counter and display driver IC to flash eight LEDs in an apparently random manner. It can be used to create a display of your choice. __ Designed by John Hewes
Reduced Power Sequential LED Flasher - The 74HC4017 is a neat decade counter which has 10 decoded outputs. When supplied with a low frequency clock and with a LED attached to each of the outputs, an interesting ten step sequential flasher effect can be produced. The LEDs can be configured in . . . Hobby Circuit designed by Dave Johnson P.E.-November, 2008
Repetitive trigger - Based on the 555 timer IC, useful for strobe lights. A bit on the 4017 counter IC for multiple flashes and sequences of flashes __ Designed by Don Klipstein Restaurant Table Service Request Flasher - A single 3v lithium coin cell battery powers the device. Four super bright green LEDs are flashed when the assembly was rotated into the “Requested Service” position. A tilt switch senses when the device is in that position. A simple timer turns off the flasher after 3 minutes, if left in the flashing position. . . . Dave Johnson, Lubbock TX-DC Magazine - Issue 13 Nov 2010Revisited-Model Train Lighthouse Flasher - This was originally designed for a model in a HO train set. It simulates the behavior of the light from a lighthouse. The LED intensity gradually increases, then flashes with a bright light and finally decreases slowly in intensity . . . Hobby Circuit designed by David Johnson P.E.-July, 2006
Ring-Around LED Flasher - This schematic diagram shows a ring-around LED flasher circuit. This circuit will turn off two LEDs and turn on the other two until the timing cycle reverses. This circuit can be configured to flash four LEDs in sequential order by pressing and holding S1 closed until only one of the LEDs is on then releasing it.
Ringing Phone Light Flasher - This is very useful in a situation were there is lots of noise and it is impossable to hear the phone, such as a workshop. Here is such a device. The ring detect part of this circuit came from [url]http://www. hut. fi/Misc/Electronics/circuits/telephone_ringer. html[/url]. Notes: 1. You may need to use a lower voltage zener for D1 and D2.2. You can use a regular relay instead of a solid state relay, but the arcing accross the contacts may destroy it pretty quickly.3. Be very sure that you have not accidentally connected 120V to the phone line when building and installing this __ Designed by Aaron Cake
Rotating & Flashing 230V Lights - This design can be of some interest for those wanting striking light signs, as it can drive up to three 230V lamp strings in three operating modes. The 15V dc supply is obtained from a nominal 230/24V center tapped ac transformer (T1) and a full wave rectifier __ Contact: Flavio Dellepiane, fladello @ tin.it
Running LED - Just for fun I designed and tested two running LED circuits based on CD4017. The first one drives a strip of six LED, while the second one works for a strip of eight LED. Both circuits work in bidirectional running __ Designed by Andrea-Central Italy |
