4×4 Matrix Keypad Module In Pakistan

The WTV020SD is a small, simple IC for embedding audio playback into your next project. These devices are commonly used in children’s toys and talking retail displays. This breakout board allows you to access the functionality of the WTV020SD to give a voice to your next project. The breakout board includes a battery connector and a micro-SD card slot. Simply load your audio files onto a micro-SD card and plug it in, power up the module, and trigger the playback. Playback can be triggered in either key or serial mode: The key-mode provides a stand-alone operation where a host micro is not required. With only 3 push buttons, a 3V battery, and a speaker, an extremely compact and low component count MP3-Player-like system can be implemented. The serial mode provides a simple, 2-wire interface to any micro-controller via its DATA and CLK lines. Audio operations such as PLAY, PAUSE, STOP, and VOLUME control functions are all available to the host micro via simple serial commands. The audio compression used in this module is a little strange (4-bit ADPCM @ 6-32kHz) so you’ll need to download the utility in the documents below in order to convert yours. WAV files into the 4-bit ADPCM format required.

The MQ135 MQ-135 MQ 135 Air Quality Detector Sensor Module For Arduino has lower conductivity in clean air. When the target combustible gas exists, the conductivity of the sensor is higher along with the gas concentration rising. Convert change of conductivity to the corresponding output signal of gas concentration. The MQ135 MQ-135 MQ 135 gas sensor has a high sensitivity to Ammonia, Sulphide and Benzene steam, also sensitive to smoke and other harmful gases. It is at low cost and suitable for different applications such as harmful gases/smoke detection.

The MAX9814 is available in the space-saving, 14-pin TDFN package. This device is specified over the -40°C to +85°C extended temperature range. MAX9814 is a low-cost, high-quality microphone amplifier with automatic gain control (AGC) and low-noise microphone bias. The device features a low-noise preamplifier, variable gain amplifier (VGA), output amplifier, microphone-bias-voltage generator, and AGC control circuitry. The low-noise preamplifier has a fixed 12dB gain, while the VGA gain automatically adjusts from 20dB to 0dB, depending on the output voltage and the AGC threshold. The output amplifier offers selectable gains of 8dB, 18dB, and 28dB. With no compression, the cascade of the amplifiers results in an overall gain of 40dB, 50dB, or 60dB. A trilevel digital input programs the output amplifier gain. An external resistive divider controls the AGC threshold and a single capacitor programs the attack/release times. A trilevel digital input programs the ratio of attack-to-release time. The hold time of the AGC is fixed at 30ms. The low-noise microphone-bias-voltage generator can bias most electret microphones.