Ultrasonic Distance Sensor

Requirements

• 1mm accuracy optimal, 3 mm is absolute max
• Open source version of http://www.cnccontrols.com/thcontrol.asp - 20-250 mm range for pointing to metal, with no obstructions

Tech Support

• Sparkfun has them - [1]. Online chat at https://www.sparkfun.com/technical_assistance
• Banner Engineering - $121 - [2]

YouTube

• Ultrasonic sensor on plasma table - [3]

R&D

• From EMC list [4] - Banner Engineering sensor PDF - 1-11" range - [5]
• Making a better HC-SR04 distance sensor - Emil - [6]

Selection

• Maxbotics - 1 mm resolution options, not water protected - 12" minimum distance - $40 - [7]. Adafruit has it.
• Microptik - 3 mm resolution - http://www.micropik.com/PDF/HCSR04.pdf - 2-400 cm range - services@elecfreaks.com. Sample Arduino sketch - [8]
• HC-SR04 - appears to get 3 mm accuracy - [9]. Sparkfun has the sensor + code - [10]

• Video shows 15 cm measurement, with oscillation +- 1mm - and text says well within 2% accuracy. 2% of 15 cm is 3 mm - so this would do for measurements of torch height for 1/2" steel easily (12 mm thickness).

Comparisons

• http://www.robotshop.com/en/compare-infrared-ultrasonic-distance-sensors.html

Explanation

• Nice video - [11]

Sourcing

• VexIQ - sensor for robots - [12]
• 4-30 cm - $99 - [13]
• 1-100 inch - $25 - [14]
• $4 Sparkfun - 6"-10' - [15]
• $6 - .5 cm accuracy - [16]