Interfacing multiple LCDs using two wire interface

LCDs using two wire interface

First thing that comes to the head is why use multiple small LCDs instead of on bigger. But you never know what situation may occur. For this purpose Jesus Echavarria have designed a special board – I2C I/O expander based on MCP23017. It is capable of expanding I2C to 16 I/Os. So he has plenty of these, so why not to try driving 8 LCD using single I2C interface. As driving MCU he uses AT89C51RE2 microcontroller board. Each expander board has its own I2C address by using three jumpers (total 8 possible slaves). The other is left for MCU software to talk to each slave and send LCD commands. I2C interface is more short distance communication interface, so if you wish to connect remote LCDs you may look for different solutions like RS485, CAN etc.   Continue reading

The Data Acquisition and Logging System Based on AT89C51

Do you ever get involved with the data acquisition and logging system? For those that have didn’t familiar with the data acquisition and logging system, it is a device that has been specially designed to measure and log some parameters. The main purpose of the data acquisition system is analysis the logged data and improves the object of measurements. Most of the data acquisition and logging system is electronic based, where it can be made of hardware, software or both of them. Let’s pay your attention on this project. The data acquisition and logging system is based on AT89C51, where it’s a microcontroller project log the temperature system. It can be used to monitor and control environment temperature. The things should know about this project is although it’s controlled by AT89C51, but it managed to control the status and temperature date saved to PC via serial communication without any hassle! Eight temperature sensors are connected to this project, where four of them were shown in diagram for simplicity. You can easily detect values of all the sensors, as the software… Continue reading