I'm new here, so I'm not quite sure, this is the right place to write, to ask.
I'm writing a program for arduino, and I've got into some trouble.
In the end, I want my program to show the status of a sensor, connected to the arduino. This status must be read from the sensor, stored at EEPROM (arduino storage) and then, when there is no connection to the sensor, the status must be read from EEPROM.
Actually, in the end there will be two arduinos communicating wireless. But my problem is, when there is connection between the sensor, and the arduino, the sensor sends out HIGH (4V) and LOW (0V). When there is no connection, the arduino must read from EEPROM, BUT it also wants to read from the sensor, and since this is not connected, the arduino receives 0, same as LOW :(
How can I program the arduino to distinguish between LOW (0V) and 0 (disconnected)?
I realle hope you can help, and sorry for bad language, I'm Danish :)
One last thing, if anybody answers, I'm no expert on this, so please write some code, you think would work, and then try explain it. I won't be able to write code from an answer...