Simple LED Volt Meter

A simple LED Volt Meter using Zener diodes as switches. If it is connected to a 12 Volt battery it shows the following indications.


Flash LED Blinks – Above 13 volt – Fully charged
Green LED lights – Above 11.8 V
Yellow LED lights – Above 11.5 V
Red LED lights – Above 10.6 V

If all LEDs light, battery voltage is above 13 volt and fully charged

DC-DC Converter Module. Application Circuit 6

This is an excellent DC- DC Converter Module that can adjust the output voltage to any desired value, even fractions from 0 V to 17 V. It is a very good Variable Power supply Module. But pressing the switch we can adjust the output voltage. It can handle a Peak current of 3 Amps. The output voltage and current are displayed in an LCD Screen that has back light. If the input voltage is from a Battery, the LCD display shows the Battery Level also.  Input voltage can be between 5V and 23 V but the best voltage is 20 V. It has 95% conversion efficiency and 1% LCD accuracy. It is available with a transparent casing. You can fix it in the case provided along with the Module.It can be connected to the Bread board so that we can determine the current consumed by the project.  Its cost is just Rs.350.
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IR Sensor Tester. Application Circuit 5

ir-sensor-tester-1Here is a simple tester to test the IR Sensor TSOP 1738. It is a highly sensitive device that damage easily if its input voltage rises above 5V. This Tester can be used to test TSOP 1738 before using in a circuit. It confirms the condition of the Sensor, whether it is functioning properly or not. It can also be used to check the IR Sensors kept in your junk box so that you can keep only the good one for use.

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IR Transmitter Tester. Application Circuit 4

ir-transmitter-circuitWe make Infrared Transmitter circuits to generate Pulsed Infrared rays to use with IR Sensor based receivers. The IR Transmitter circuit based on IC 555 generates IR rays pulsating in the frequency typically at 38KHz. The IR Sensor used in the receiver is TSOP 1738 which also works in the same frequency. So here is a simple IR Transmitter Tester to check whether the IR Transmitter is emitting 38 KHz frequency or not.
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Hacking a Remote. Application Circuit 3

remote-5We construct different types of Infrared Receiver LED ( Rx) or IR Sensor ( TSOP 1738 ) based circuits. To test, the working of the circuit we have to use an IR Transmitter. Usually we use IC 555 based IR transmitter for this. But the frequency of the IR from the Transmitter should match with that of the Sensor, otherwise the circuit will not respond. Here is a simple solution to test the IR based circuits. Simply Hack a Mini Remote obtained along with low cost FM radio, Toys etc. You have such Remotes in your Junk box. Let us Hack one such Remote to make a Tester.
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IR LED Tester. Application Circuit 2

led-testerIR Rays are invisible to human eye, so it is very difficult to check the working of IR LED. Usually we use a Mobile camera to test IR LED since the pink light from the IR LED becomes visible in digital camera. We can make a simple IR LED tester so that, before using it in the project, we can confirm whether it is good or not. Lot of IR LEDs are also in our Junk box. So we can check all IR LEDs and  discard the damaged ones. The same tester can be used to check all ordinary LEDs, Photo diodes, Silicon and Germanium diodes etc.

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Deterrent Light. Application Circuit 1

Install this Deterrent Light in your Home backyard and Porch to thwart the attempt of Burglary. This PIR Motion Sensor based light switches on instantly when it detects a Human movement from a distance of ten meters. The light turns on for 3 minutes and then turns off. It Re triggers again if the movement continues. Relay is used to drive the load, so any kind of lights can be used.
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