Arduino Development Board Compatibility
The tutorials and demos presented by Parallax are intended for, and tested on, the Arduino Uno development board. Other Arduino boards may not be compatible with all examples. This is due to the differences in the architecture between the various types of Arduino boards now available.
Here are some of the major variances between the more popular Arduino boards. In some cases, you can alter the connection and sketch code to make the example code compatible. But in other cases, use of certain Arduino boards with any example is specifically not recommended.
I2C Interface Pins
On the Arduino Uno, the I2C data and clock interface is "hard wired" to pins A4 and A5. Check the documentation for the board you are using to determine if it uses different pins for I2C communications. If so, connect your I2C-compatible module to those pins, and modify the sketch accordingly.
For example, on the Arduino Mega2560, the I2C interface is on pins 20 and 21.
5 Volt (In)tolerance
The Arduino Due uses 3.3V power. Its I/O pins are not tolerant of 5 volt inputs. Connecting a sensor that delivers a 5V signal to an Arduino Due may cause irreversible damage to your Arduino board. This is true even if you insert a current-limiting resistor inline between the microcontroller pin and sensor.
To resolve this problem consider powering the sensor at 3.3V only (if compatible), or using logic-level translation. These techniques are for advanced experimenters only.
Voltage Regulator Limitations
The 5 volt voltage regulator on the Arduino Uno provides up to 1 amp of current, enough to power the Arduino itself, as well as several attached sensors and peripherals. Mini- and micro-sized Arduino boards often use smaller onboard voltage regulators that provide less current. These boards may not be able to support external components, such as motor servos, that draw extra current. In such cases you need to power the device(s) from its own separate regulated power source.
3.3V Power Supply
In addition to the Arduino Due noted above, some specialized Arduino boards -- such as the Arduino Pro Mini -- are designed to be powered from a 3.3V source. These boards are intended to be used with sensors and other peripherals designed for 3.3V operation.
These specialty boards run at only half the clock rate of an Arduino Uno, and may require special versions of third-party libraries. Results can be unpredictable. They are not recommended for use with the KickStart examples.
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