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SRF-10

The SRF-10  is a compact ultrasonic range finder, identical in operation to the SRF-02. The advantage of the SRF-10 is more reliable readings, especially in the center "blind" spot.

See the specs for the SRF-02 for information on accessing the unit on the I2C bus as well as changing the address of the unit if needed.

Application Notes

Analog Gain

When we mounted the SRF-10 on the mast of our robot, we noticed that we failed to get readings above ~33cm or so. We pinned this down to an echo the unit was receiving from the tires of the bot, almost exactly 33cm from the sensor. We tilted the element up by 15 degrees, but this only marginally improved the erratic readings.

We then adjusted the analog gain of the sensor down to about half of what it was, and this eliminated the problem entirely. There are full instructions on the datasheet linked above, but it was as simple as writing 0x08 to register 0x01 on the unit. We might run some more tests and tweak both this number as well as the maximum ranging distance to see what gives us the best results.

Neither of these values can be changed on the SRF-02, giving the SRF-10 another advantage (as well as a $40 jump in price)

Mounting

We purchased the SRF-10 mounting kit along with the sonar unit, and it proved to be worth every penny of the $8. We were able to mount the unit on a servo, allowing us to do the work of 2+ units by simply rotating the head to the desired position of ranging.