This Sensor Networking Device is able to read and write from multiple sensors from a webpage. The sensor data is transfer via RS485 communication to a raspberry pi where the data is sent to a webpage using php.
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Step 1: Hardware
The list of hardware needed:
1. Raspberry Pi
2. Sensor or sensors that use RS485 communication
3. RS485 to usb converter
4. Power supply for the sensor(s)
5. LCD Display that uses RS485 communication
6. Ethernet Cable or you can just broadcast it over wifi
7. Connector for all the RS485 devices along with a 100 ohm resistor to connect between the two data wires(green and white wires). You can use a bread board if that's easier.
Step 1: Connect the RS485 communication wires and the GND wires from the sensors and display to the RS485 to usb converter.
Step 2: Connect the usb cable to the RS485 to usb converter and the raspberry pi.
Step 3: Connect power to the sensors and display.
Step 4: Connect Ethernet cable to your computer.
Step 5: Plug in the power cable for the raspberry pi.
Step 2: Setup the Raspberry Pi
For the basic setup of a raspberry pi go to https://www.raspberrypi.org/help. Next follow the setup instructions on the raspberry pi website to install php and apache by clicking on this website: https://www.raspberrypi.org/documentation/remote-a...
Step 3: Webpage
This is a simple webpage that uses php and html but also is able to use modbus to read/write to the sensors and display. The php serial modbus code in PhpSerialModbus.php was obtained thanks to Toggio and is found on github by this link https://github.com/toggio/PhpSerialModbus. The code in file index.php that is found in the attachment index.pdf. Connect to your raspberry pi by typing into your web browser the IP address you are broadcasting on the raspberry pi.
Step 4: Video of Working System
Here is a video of a working system