Arduino Library for the ADXL345 accelerometer.
I have tried to create a library for the ADXL345 which is easy to use for people who don't want to deal with all the registers. Therefore I have added lots example sketches which will enable you to deal even with the more complex features such as the FIFO modes. Howerever I still recommend to have a look into the data sheet to get a deeper understanding.
You can use both I2C and SPI. If you want to find out how to use SPI, look at the ADXL345_SPI_basic_data.ino.
A detailed tutorial is available:
https://wolles-elektronikkiste.de/adxl345-teil-1 (German)
https://wolles-elektronikkiste.de/en/adxl345-the-universal-accelerometer-part-1 (English)
If you are not so much experienced with the ADXL345, I recommend to work through the examples in the following order:
- ADXL345_basic_data
- ADXL345_SPI_basic_data
- ADXL345_calibration
- ADXL345_angles_orientation
- ADXL345_pitch_roll_corrected_angles
- ADXL345_sleep
- ADXL345_free_fall_interrupt
- ADXL345_data_ready_interrupt
- ADXL345_activity_inactivity_interrupt
- ADXL345_auto_sleep.ino
- ADXL345_single_tap
- ADXL345_double_tap
- ADXL345_fifo_fifo
- ADXL345_fifo_stream
- ADXL345_fifo_trigger
To develop this library I have worked with a ADXL345 module. It should also work with the bare ADXL345 IC. For the module I have noticed that the power consumption is much higher than mentioned in the data sheet. I think the issue is the voltage converter on the module. You can reduce the power consumption by choosing 3.3 volts instead of 5 volts. At least this worked with my module.
If you like my library please give it a star. If you don't like it I would be happy to get feedback. And if you find bugs I will try to eliminate them as quickly as possible.
My library has implemented SPI 4-Wire. Some modules have SDO connected GND via an 0 ohm resistor. With this resistor only SPI 3-Wire would work. Your options are:
- Remove the 0 ohm resistor connected to SDO (R4 on my module)
- Replace the 0 ohm resistor connected to SDO by an internal or external pull-down resistor of 4.7 kohm or 10 kohm
- Find another library which supports SPI 3-Wire
Another SPI issue might occur when using ESP8266 boards like the WEMOS D1 mini or NodeMCU. The standard CS Pin (e.g. D8/GPIO15 on a WEMOS D1 mini or NodeMCU) might not work since the CS Pin on most ADXL345 modules has a pull-up resistor. And if D8 is high at reset, the ESP8266 will not boot. In that case choose a different ESP8266 pin as CS!