Product Information

LED
The red LED is used to flash out a code for the I2C address on power-up (see below). It
also gives a brief flash during the "ping" whilst ranging.
Changing the I2C Bus Address
To change the I2C address of the SRF08 you must have only one sonar on the bus. Write
the 3 sequence commands in the correct order followed by the address. Example; to
change the address of a sonar currently at 0xE0 (the default shipped address) to 0xF2,
write the following to address 0xE0; (0xA0, 0xAA, 0xA5, 0xF2 ). These commands must
be sent in the correct sequence to change the I2C address, additionally, No other
command may be issued in the middle of the sequence. The sequence must be sent to the
command register at location 0, which means 4 separate write transactions on the I2C
bus. When done, you should label the sonar with its address, however if you do forget,
just power it up without sending any commands. The SRF08 will flash its address out on
the LED. One long flash followed by a number of shorter flashes indicating its address.
The flashing is terminated immediately on sending a command the SRF08.
Address
Decimal Hex
Long
Flash
Short
flashes
224 E0 1 0
226 E2 1 1
228 E4 1 2
230 E6 1 3
232 E8 1 4
234 EA 1 5
236 EC 1 6
238 EE 1 7
240 F0 1 8
242 F2 1 9
244 F4 1 10
246 F6 1 11
248 F8 1 12
250 FA 1 13
252 FC 1 14
254 FE 1 15
Take care not to set more than one sonar to the same address, there will be a bus collision
and very unpredictable results.
Current Consumption
Average current consumption measured on our prototype is around 12mA during ranging,
and 3mA standby. The module will automatically go to standby mode after a ranging,
whilst waiting for a new command on the I2C bus. The actual measured current profile is
as follows;