I want to use three identical adxl345 accelerometers on the same i2c bus.
How is the procedure to give each device its own unique address to separate them?

If this example is incorrect please let me know:

If I connect SDO of the first adxl345 to GND I will get address (0×52) and the SDO of the second adxl345 to the vcc I will get address (0×53). How is it possible to make an address to the third adxl345?

How about connecting the SDO pins of each of the units to separate digital output pins on the Arduino. Select the unit you want to talk to by bringing its SDO pin low (with the other two high) and use the alternate address (0xA6 write & 0xA7 read) in all cases.

Note the addresses are 0x3A & 0x3B with SDO High and 0xA6 & 0xA7 with it low if I read the data sheet correctly.

please don't cross post !!

@MikMo, sorry I wasn't sure if it was a hardware or a software topic.

@RoyK, thanks for the replay!