Sonar / Ultrasom / Anti-colisão

Anti-colisão (Sonar)

Meus sonares Cytron HC-SR04
[ http://www.cytron.com.my/viewProduct.php?pcode=SN-HC-SR04 ]

http://dx.com/p/hc-sr04-ultrasonic-sensor-distance-measuring-module-133696

(cerca de $4)

HY-SRF05
http://dx.com/p/hy-srf05-ultrasonic-distance-measuring-sensor-module-for-arduino-147397

(cerca de $6)

US-020
http://dx.com/p/us-020-ultrasonic-sensor-distance-measuring-module-green-silver-199047
(cerca de $5)