code and fabrication resources for physical computing and networking
tigoe.net | pcomp home | blog | code, circuits, & construction | my del.icio.us links
{ Category Archives }
Here’s a short Wiring/Arduino program that waits for a connection to the microcontroller via a Lantronix device, and sends out an analog reading when it’s got a connection.
The Lantronix device is in connectMode D4, and the TX is connected to the Arduino’s RX and vice versa.
Sensorbase.org is an open data repository run by the Center for Embedded Networked Sensing at UCLA. It’s a database of sensor databases. You can upload datasets to it, and you can browse other datasets as well. If you’ve never set up a database before but are interested in logging sensor data, it’s a good tool to get started. If you know what you’re doing already and you need to log a lot of sensor data, or compare it to similar work from others, it’s a convenient tool.
Since I like working with sensors and microcontrollers connected directly to the Internet, I thought it would be useful to be able to put data directly into Sensorbase from sensors connected to a microcontroller, without a personal computer in between.
If your router doesn’t disclose the IP table, there are at least five ways you can discover the Xport’s IP; one PC-dependent, one Mac-dependent, and three platform independent.
Technorati Tags: networked objects, networks
This is a very simple program to test the serial-to-ethernet connections of a Lantronix device connected to an Arduino or Wiring board.
Technorati Tags: networked objects, networks
This program connects a Wiring or Arduino module to the internet through a Lantronix serial-to-ethernet converter (Xport, WiPort, or Micro). The microcontroller makes a TCP connection to a web server first. Once it’s got a connection, it sends an HTTP request for a web page. When the web page comes back, it parses the page for < and > symbols, and takes the string between them. Then it converts the string to an integer. It assumes the string is made only of numeric ASCII characters (0 - 9).
This program couldn’t parse an entire web page very easily, so it’s best used in conjunction with a web scraper PHP script like this one, which reads the AIRNow site and extracts the Air Quality Index into a single string like this:
< AQI: 54>
This program was written to make an air quality index meter out of an analog voltmeter.
The electrical connections to the microcontroller are as follows:
The web scraper is written in PHP. Its code follows below the Arduino code.
Technorati Tags: networked objects, networks
This program connects a microcontroller to a mySQL database via a Lantronix Xport and a PHP script.
The PHP script it uses is the SQL_datalog.php script in the Network Data Logging Suite.
Technorati Tags: networked objects, networks
The Cobox Micro can send and receive UDP packets. I haven’t written examples yet. Following are just my notes, from discussions on the Lantronix Xport Yahoo mailing list, and from experimentation.
To send directed UDP packets, you have to put set the connectMode appropriately. Bits 2 and 3 of the ConnectMode register are set to 1 to enable directed UDP. Setting the ConnectMode to 0xCC (hex) will set the Cobox to accept any incoming UDP packets and allow you send UDP packets to the address and port number you set for the remote IP address. Once you’ve set the ConnectMode to 0xCC, set the Datagram Type to 01. With these settings, your cobox will only send to the remote IP specified in your configuration.
It is possible to change the destination address on the fly. It’s undocumented, but the Lantronix folks on the list have been helpful in figuring it out. First, you have to set the ConnectMode to CC and the Datagram type to 00. In this configuration, you have to compose your own outgoing datagrams, as follows:
Continue Reading »
This program waits for the Lantronix device to give an acknowledgment of a net connection before it starts to send data. The Lantronix Device has to have its connect mode set to verbose, so that it will send ASCII N when not connected, ASCII D when disconnecting, and ASCII C when a connection is made.
Technorati Tags: networked objects, networks
