Infrared audio headphone link for TV

To listen via headphones preferably good ‘surround your ears’ muff-type headphones, which not only deliver the wanted sounds directly to your ears and hearing aid(s) but also cut back the competing sounds at the same time. If you pick the right kind of headphones, with some acoustic damping in the earmuffs, they don’t cause your hearing aid(s) to emit feedback and whistle sounds either.

The result is comfortable listening at a volume level that’s right for you, where you can hear and understand everything that’s being said.

Headphone jack
Some TV sets do have earphone jacks, so you could simply fit a pair of stereo headphones with their own volume control (if necessary), plus a long cord and plug to mate with the jack on the TV. But many sets do not have a headphone jack, and many that do have it wired so that when headphones are plugged in, the speakers are disabled.

That’s fine for you, but no good for everyone else. In any case, being hooked up to the TV via a long cable has its own problems: you can forget to take ’em off when you get up for a comfort break or someone else can trip on the cable when they move about the room.

Universal Remote Control Receiver

The circuit diagram shown in Fig.1 uses a PNA4602M IR detector to receive an IR signal from  the remote control. It’s a neat device, which contains an IR receiver, amplifier and demodulator together in a single 3-pin package, and it’s normally used in circuits where you want to decode an IR remote control signal. 

The way the circuit (Fig.1) works is as follows. When there is no IR coded signal present, the output pin of IC1 remains high. This high signal is fed to the trigger input of the 555 timer (IC2), which being configured as a monostable timer, prevents the timer operating. 

Whenever you briefly press any key on the old remote control its IR signal is received by IC1 and output pin 1 produces a train of fast moving high and low pulses, which mimic the IR signal code sent by the remote control. We are not interested in this code, but as soon as the signal switches low it triggers the monostable timer IC2 and its output pin 3 goes high for a short period of time, set by resistor R2 and capacitor C2.

Long-Range IR Transmitter

Most of the IR remotes work reliably within a range of 5 metres. The circuit complexity increases if you design the IR transmitter for reliable operation over a longer range, say, 10 metres. To double the range from 5 metres to 10 metres, you need to increase the transmitted power four times.

If you wish to realise a highly directional IR beam (very narrow beam), you can suitably use an IR laser pointer as the IR signal source. The laser pointer is readily available in the market. However, with a very narrow beam from the laser pointer, you have to take extra care, lest a small jerk to the gadget may change the beam orientation and cause loss of contact.

Contact less IR tachometer using PIC16F628A

Tachometer is a device that gives the information about the rotational speed of any shaft or disc. It usually measures the speed in revolutions per minute (RPM). 

I want it to measure the speed of motor so for this i searched the net and found various design but unfortunately they don't worked for me, don't know why?. So i decided to make my own tachometer using PIC16F628A micro-controller and LCD.

SIRC Decoding and Appliances Control

In this tutorial i will show you how to decode the Sony SIRC protocol and control the home appliances like bulb, fan etc with the Sony remote control. Infrared remote control has been around for a very long time now. Each manufacturer use different set of protocols. For example, RC80 is used by Panasonic, RC5 is used by Philips, and SIRC is used by SONY, which is one of the simplest to decode.

Modulation is used to prevent the other light sources interference. This modulation is center around different frequencies depending on manufacturer and varies from 32KHz to 56KHz. In the case of SONY, the modulation center is 38-40KHz which means we need a IR-receiver that can receive the modulation infrared light and convert it to a TTL signal for a PIC. There are a number of IR-receivers available, each having a specific center frequency that they are more sensitive too.You can use whatever you want just remember the pin outs; i am gonna use to local IR receiver.