Tag: sensors

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Arduino INPUT_PULLUP mode

notes

When reading the value of a switch with Arduino, its useful to set the INPUT_PULLUP mode so you don’t need to use an external pullup resistor. By the way, the internal pull-up resistor is 20K ohms.

See this tutorial:

http://arduino.cc/en/Tutorial/InputPullupSerial

If its not clear what a pull-up resistor does,  read the links on this forum post.

http://arduino.cc/forum/index.php/topic,22274.0.html

Everybody has their own way to explain it. I would say that when the switch is open, the pull-up resistor weakly pulls the logic value high, so you don’t get random signal readings.

 

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Arduino pachube (cosm) feed for musical stairs

(update) the feed is working – I changed the datastream name from sensor_value to count – and just had it upload a random value every time for testing.

Some initial testing with the Ethernet shield encountered missing libraries when compiling the example sketch which cosm.com provides when setting up an Arduino type feed.

Here is the forum post which explains which libraries are missing:  http://community.cosm.com/node/1694

and here is the helpful quote…

You should try using new official Cosm library for Arduino.

You can download a snapshot zip file here:
https://github.com/cosm/cosm-arduino/zipball/master

You will also need this HTTP library:
https://github.com/amcewen/HttpClient/zipball/master

See here for more details on how to install a 3rd-party
library on different OS:
http://arduino.cc/en/Guide/Libraries

You will find a bunch of usefull examples within the
Cosm library. Please let me know if you have any questions.