Readings can be taken faster if absolutely required, but this will limit the maximum range of the sensor. Because of this, read_sensor() is called after at least 100ms has elapsed after running the function start_sensor(). Notes: The I2C‑MaxSonar sensors are configured to report the last range reading stored in memory. A value of “0” represents that the sensor could not be read and that there was an error in communication. Returns: range: an int value corresponding to the distance found by the sensor (for the current I2C‑MaxSonar sensors this is a value between 20cm and 765cm).
The default value for I2C‑MaxSonar sensors is 224. Parameters: addr: an even byte value corresponding to the 8-bit address you are reading from. Using an odd value will cause the address to automatically be rounded down to the next lowest even number when used.ĭescription: Uses the I2C library to read a sensor at the given address. Note 2: addr is always an even value with the last bit being reserved for a Read/Write signal as defined by the I2C specification. Commanding more than one sensor to range at once may cause cross-talk (interference). Note 1: Care should be taken to only operate one sensor at a time. Set to TRUE (value of 1) if there was a communication error. Returns: errorlevel: defaults to FALSE (value of 0) when the communication is successfully completed. Parameters: addr: an even byte value corresponding to the 8-bit address of the sensor you want to command a range reading at. You must start the sensor 100ms before requesting a range from it if you want the most recent information. The included functions and their related information are as follows:ĭescription: Uses the I2C library to start a sensor at the given address.
#Arduino i2c example sketch code#
If you have other devices on the I2C bus, make the proper modifications to the code to run your other devices as needed. These functions are included so you can easily talk to the I2C‑MaxSonar sensors. (You should read the code notes for that.) I have provided a brief description of what I did at each point. I do not go into every detail in this article. I have included 3 functions (one for each command the sensor can do) and 3 different code examples (one for each type of activity a typical user will have to do). Read the Sensor Example (runs continuously) – The code will take a range reading from a connected I2C‑MaxSonar at the default address of 224 and output the range information that it received. Change Address Example (runs once) – The code will take a range reading at the default address of 224, change the sensor address to a new address of 222, take a range reading at the new address, then change back to the default address.ģ. The rest of the code assumes that the I2C‑MaxSonar is located at its default address of 224.Ģ. Address Polling Example (runs once) – The code will poll all of the available I2C addresses and look for connected I2C‑MaxSonar sensors. Please note that the I2C‑MaxSonar Arduino code defaults to running 3 different code examples.ġ. You should now have the I2C code running and reading the connected sensor. I am grateful for their work, as it means I did not have to write my own library. Thankfully, Peter Fleury and Bernhard Nebel were able to write an I2C library that uses a bit‑bang approach and has a nifty set of user defined parameters for greater flexibility in our interface. Neither of these combinations are available without taking more direct control. This makes the default library only marginally functional with an I2C‑MaxSonar because the I2C‑MaxSonar currently only supports bus speeds up to 50kHz (without clock stretching) or 400kHz (with clock stretching).
Use a library because the default Arduino Wire() library does not support changes in bus speed or feature proper clock stretching support. The recommended solution is to use the SoftI2CMaster library shown below. This functionality, however, takes advantage of a timing slowdown in the current Wire() library. Note: Any I2C‑MaxSonar sensors shipped after 10/29/14 were updated to support faster speeds and work with the current Arduino Wire() library. I have also provided some of the educational information related to this specific I2C implementation. Never fear! I have worked to provide a clear and easy to follow path to get an I2C‑MaxSonar up and running on your Arduino.
#Arduino i2c example sketch install#
The short answer is “Yes.” The more technical answer is – be prepared to install a new library and learn a bit about digital electronics. A number of customers have asked if the Arduino supports talking to the I2C‑MaxSonar sensors over an I2C interface.
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