I would like to build a sensor that can transmit data wirelessly (zigbee) and securely, to be decoded and displayed on a small LCD screen of a passing mobile device. The idea is to have the transmitter fixed and the receiver mobile.
I have thought about using an Arduino basic kit, with a XBEE shield and an LCD Shield. I am not too familiar with any of this so any help/advice would be appreciated. All needs to be battery and/or solar powered.
Example Scenario: We would setup a transmitter on a wall. When passing by the wall, the receiver would see on the LCD - passing green wall. A second transmitter on another wall. The receiver displays passing red wall.
Hey thanks! Is it relatively easy to interface with a standard LCD? ie -what would control it?
Also, I would like to have the receiving device in a moving vehicle like a car or bicycle and have the speed of the vehicle displayed too. someone said that I would need a GPS Shield to get the speed information and then use that data to display it on the LCD too. Is there any simpler way you know?
Finally, Is there such a thing as an interface to a Garmin NUVI GPS or other commercial GPS that allows the data to be tramitted in real time to the arduino kit?
Welcome to the RobotShop Forum. You are on the right path - an Arduino with XBee shield as well as an LCD shield would work, except for the fact that the two don’t stack very well. In this case, you might just consider a standard LCD display. If you really want to consider an LCD shield, just be sure the pins from the XBee shield do not interfere with the pins used bu the LCD shield (especially the Tx and Rx used for serial communication). If you want to use a serial LCD screen, the Arduino MEGA has 3 serial I/O lines.
Fortunately there is a lot of sample code available for Arduinos, including how to use an LCD. If you want to use XBeem that takes up a serial line, so if you are using the Duemilanove, you should consider an LCD with I2C or parallel interface. The MEGA has 3x serial lines, so one could be used by the XBee and another by a Serial LCD, and a third by a serial GPS unit (if that is what you want). To get the speed from a bike, you can use an accelerometer (the data can be integrated to give you an idea of the velocity). A GPS would provide you with positional data and time which you then use to get the velocity. If you use both, you will get a more accurate velocity reading. We are not aware of any interface between a handheld (or car mounted) GPS unit, but we would not be surprised if one exists somewhere or will be created soon. If you can find a bluetooth enabled GPS unit, you may be able to hack into the signal to get the raw data (coordinates), but this is far from the “easiest” approach.
