Take care not to set more than one sonar to the same address, there will be a bus collision and very

unpredictable results.

Note - there is only one module address stored in the SRF02. If you change it, the equivalent I2C address

will also change:

0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B,

0x0C, 0x0D, 0x0E, 0x0F Serial addresses

0xE0, 0xE2, 0xE4, 0xE6, 0xE8, 0xEA, 0xEC, 0xEE, 0xF0, 0xF2, 0xF4, 0xF6,

0xF8, 0xFA, 0xFC, 0xFE Equivalent I2C addresses

AutoTune

The SRF02 does not require any user calibration. You power up and go right ahead and use the SRF02.

Internally, there are tuning cycles happening automatically in the background. After the ultrasonic burst has

been transmitted, the transducer keeps on ringing for a period of time. It is this ringing which limits the

closest range the SRF02 can measure. This time period varies with temperature and from transducer to

transducer, but is normally the equivalent of 11 to 16cm (4" to 6"), a bit more if the transducer is warm. The

SRF02 is able to detect the transducer ring time and move its detection threshold right up to it, giving the

SRF02 the very best performance possible. On power up, the detection threshold is set to 28cm (11"). The

tuning algorithms quickly back this right up to the transducer ring. This happens within 5-6 ranging cycles -

less than half a second at full scan speed. After this the tuning algorithms continue to monitor the transducer,

backing the threshold up even further when possible or easing it out a bit when necessary. The tuning

algorithms work automatically, in the background and with no impact on scan time.

The minimum range can be checked, if required by sending command 95. This will return the closest

measurable range in uS, cm or inches, the same as the range. It is also possible to make the SRF02 re-tune

by writing command 96 but you can ignore this command. It is used during our testing.

3

03

1

3

4

04

1

4

5

05

1

5

6

06

1

6

7

07

1

7

8

08

1

8

9

09

1

9

10

0A

1

10

11

0B

1

11

12

0C

1

12

13

0D

1

13

14

0E

1

14

15

0F

1

15