This Accelerometer module is based on the popular Freescale MMA7361 three-axis analog accelerometer IC (datasheet here), which reads off the X, Y and Z acceleration as analog voltages. The accelerometer is very easy interface to an Arduino Microcontroller using 3 analog input pins, and can be used with most other microcontrollers, such as the PIC or AVR.
This module comes complete with 0.1" pitch pin headers soldered on, so it fits directly into a breadboard or prototype shield. This module's onboard voltage regulator allows for convenient operation at either 3.3 volts or 5 volts - a feature not found on the competitor's modules. No additional external components are required for operation. A sample hookup diagram for the Arduino UNO is below.
- 2x5 pin 0.1" pitch pin headers
- Two sensitivity modes ±1.5G and ±6G
- 5VDC & 3.3VDC operation
- 0G detect pin (for linear Free-Fall detection)
- Sleep Mode to save on power
- Integrated 1 pole low pass filter
- Temperature Compensation
- Self Test Mode for easy troubleshooting
- NOTE: It has been suggested that you need to use a 10K resistor to the sleep pin to power on the module.
|pin label on on the 12-pin variety||pin label on the 10-pin variety||MMA7361 pin||signal name||signal description|
|3.3V||3V3||6||VDD||power supply input|
|4||X||2||Xout||X direction output voltage|
|5||Y||3||Yout||Y direction output voltage|
|6||Z||4||Zout||Z direction output voltage|
|7||SL||7||sleep||logic input pin to enable sleep mode|
|8||8||not connected||no internal connection - leave unconnected|
|9||0G||9||0g-detect||linear freefall digital logic output signal|
|GS||10||sensitivity mode selection||When this pin is grounded or floating, the sensitivity is ±1.5G. Pull this pin high to enable the ±6G sensitivity mode.|
|10||12||not connected||unused - for factory trim - leave unconnected|
|12||14||not connected||unused - for factory trim - leave unconnected.|
The MMA7361 IC, which lies at the heart of this module, has a logic input pin called "g-select" that is used to select one of two different sensitivity modes. In the default mode, which is selected by leaving g-select unconnected, the analog outputs reach their maximal level at ± 1.5g. This mode is well-suited for measuring the direction of Earth's gravitational field when the module is not accelerating.
If you ground the g-select pin, then you tell the accelerometer to scale its analog outputs to ±6g. This mode works well when you want to measure acceleration caused by motion, whose magnitude can easily exceed the other mode's ±1.5g ceiling.
This accelerometer module operates in the ±1.5g mode by default. To turn on the ±6g mode, bridge the solder pads labeled "R2".
Applications for this device on your Arduino include navigation, motion sensing, speed/movement data logging, etc. Hey, you could make an Arduino-based pedometer. The accelerometer board is a great add-on for your Arduino projects.
Depending on availability from the manufacturer, we stock either the 12-pin or the 10-pin variant of this module, both of which are listed as VUPN5915. Only the 12-pin module is pictured here. Here are the differences between the two variants:
The 12-pin module provides header pin breakouts for MMA7361 pin 8 (not internally connected), MMA7361 pin 12 (factory trim), and MMA7361 pin 14 (factory trim); the 10-pin variant does not provide these breakouts. None of these pins is used during normal operation of the module.
The 12-pin variant provides access to MMA7361 pin 10 (sensitivity mode selection) via a surface-mount solder pad; the 10-pin variant breaks that MMA7361 pin out to a header pin, labeled "GS".