Digital & Analog Based Mini electronics Projects Page_5

Digital & Analog Based Mini electronics Projects Page_5

41. Electronic Watchdog:

Here’s an electronic watchdog for your house that sounds to inform you that somebody is at the gate transmitter is derived from the receiver circuit by connecting its points A and B to the respective points of the receiver circuit. The receiver is powered by regulated 6V DC. For the purpose, you can use a 6V battery. The transmitter and receiver units are aligned such that the IR beam falls directly on the IR sensor. As long as IR beam falls on the sensor.

42. Fire Alarm Using Thermistor:

In this fire alarm circuit, a thermostat works as the heat sensor. When temperature increases, its resistance decreases, and vice versa. At normal temperature, the resistance of the thermostat (TH1) is approximately 10 kilo-ohms, which reduces to a few ohms as the temperature increases beyond 100°C. The circuit uses readily available components and can be easily constructed on any general purpose PCB.

43. Flashing Beacon:

A flashing beacon has many uses. It can be employed as a distress signal on highways or as a direction pointer for parking lots, hospitals, hotels, etc. Here we present a flashing beacon that uses well-known regulator IC LM317T. As LM317T regulator can deliver more than 1 amp. A small 12V, 10W bulb with a high-quality reflector can serve as a good visible blinker.

44. Flashing-Cum-Running Light:

This circuit generates flashing lights in running pattern. In conventional running lights, the LEDs glow one by one. In this circuit, the LEDs flash a number of times one by one.

45. Hearing Aid:

Commercially available hearing aids are quite costly. Here is an inexpensive hearing aid circuit that uses just four transistors and a few passive components.

46. Highway Alert Signal Lamp:

Here is a signal lamp for safe highway driving. The lamp automatically emits brilliant tricolor light when a vehicle approaches the rear side of your vehicle. It emits light for 30 seconds that turns off when the approaching vehicle overtakes. The ultra-bright blue, white and red LEDs of the signal lamp emit very bright light to alert the approaching vehicle’s driver even during the day, giving additional safety during night, or when you need to stop your vehicle on side of the highway. The circuit saves considerable battery power.

47. Hit Switch:

This versatile hit switch is the electronic equivalent of a conventional switch. It can be used to control the switching of a variety of electronic devices. The circuit of the hit switch uses a piezoelectric diaphragm (piezo buzzer) as the hit sensor. A piezoelectric material develops electric polarization when strained by an applied stress. The

48. House Security System:

Here is a low-cost, invisible laser circuit to protect your house from thieves or trespassers. A laser pointer torch, which is easily available in the market, can be used to operate this device.

49. Infrared Cordless Headphone:

Using this low-cost project one can reproduce audio from TV without disturbing others. Itdoes not use any wire connection between TV and headphones. In place of a pair of wires, it uses invisible infrared light to transmit audio signals from TV to headphones. Without using any lens, a range of up to 6 meters is possible. Range can be extended by using lenses and reflectors with IR sensors comprising transmitters and receivers.

50. Infrared Firecracker Igniter:

Firecrackers are normally ignited by using a matchstick or a candle. You have to run away quickly after igniting the fuse of the firecracker. This method of igniting firecracker is unsafe, because the danger of the firecracker bursting before you reach a safe distance is always there.