Category Archives: Electronics

Bluetooth Module Serial Communication AT command set

Ref: www.linotux.ch/arduino/

HC-05 embedded Bluetooth serial communication module has two work modes: order-response work mode and automatic connection work mode . And there are three work roles (Master, Slave and Loopback) at the automatic connection work mode. When the module is at the automatic connection work mode, it will follow the default way set lastly to transmit the data automatically. When the module is at the order-response work mode, user can send the AT command to the module to set the control parameters and sent control order. The work mode of module can be switched by controlling the module PIN (PIO11) input level. Continue reading Bluetooth Module Serial Communication AT command set

GSM modem interfacing

The GSM modem, phones provides a low cost, long range, wireless communication channel for embedded, microcontroller based applications that need connectivity rather than high data rates. Machinery such as industrial refrigerators, freezers, HVAC, monitoring and vending machines, vehicle service, warning system, security system, remote control etc. could benefit from being connected to a GSM modem.

This tutorial describes how to use an AVR to control a GSM modem using AT commands. The interface between modem and host is a textual protocol called AT-Commands. These commands enable GSM modem setup, dialing, text messaging etc. This particular application connects an AVR ATmega8 and SIM300, SIM900 module using a RS232 connection. Most GSM modems have same AT commands. Continue reading GSM modem interfacing

DTMF Decoder MT8870

This circuit detects the dial tone (DTMF Tone) from a telephone line and decodes the keypad pressed on the remote telephone. The dial tone we heard when we pick up the phone set is call Dual Tone Multi-Frequency (DTMF). The name was given because the tone that we heard over the phone is actually make up of two distinct frequency tone, hence the name dual tone. The DTMF tone is a form of one way communication between the dialer and the telephone exchange. A complete communication consist of the tone generator and the tone decoder. In this article, we are use the IC MT8870, the main component to decode the input dial tone to 5 digital output. These digital bits consists of pressed key code 4-bit and 1-bit to tell that data is available. It can be interface to a microcontroller for further application such as remote control, IVRS (Interactive voice control systems) etc. Continue reading DTMF Decoder MT8870

Flow Meter using Arduino

In this tutorial we are designing flow meter using arduino, basically we use arduino boot loader controller on our custom made PCB.

A flow meter is a device used to measure the flow rate or quantity of a gas or liquid moving through a pipe. Flow measurement applications are very diverse and each situation has its own constraints and engineering requirements. Flow meters are referred to by many names, such as flow gauge, flow indicator, liquid meter, etc. depending on the particular industry; however the function, to measure flow, remains the same.

Continue reading Flow Meter using Arduino