Useful Page from CMU

other ideas:

Whisker sensors (bend sensor or PVDF...)

I thought I saw some of these laying around?


optical mouse

  • ADNK-3080 LED based sensor
  • ADNK-6000 Laser based sensor

Samples have been ordered

Possible Sensors

1 Devantech SRF08 Range Finder:

Ultrasonic, receiver & transmitter, High Price, range 3cm - 6m
2 Devantech SRF10 Ranger:
Ultrasonic, receiver & transmitter, High Price, smaller form factor, range 3cm - 6m
3 Devantech SRF05:
Ultrasonic, receiver & transmitter, Lower price, range 3cm - 4m
4 Devantech SRF04 Ranger:
Ultrasonic, receiver & transmitter, compact, range 3"-10'
5 Sharp GP2D120? IR Sensor:
IR, low price, range 4cm - 30cm
6 Sharp GP2D12? Detector Package:
IR, low price, range 10cm - 80cm
7 HSDL-9100-021:,C1,C5231,C5233,C5060,P91942
IR, surface mount package, range near zero - 60mm, susceptible to surface reflectivity?

Other notes:

From : Many ultrasonic rangefinders will report distance based on the first echo that is received and will ignore any other echoes. Some rangefinders can report multiple echoes, allowing the sensor to detect multiple objects at varying depths within the field of view. The Devantech SRF04 ultrasonic rangefinder can detect one echo in its field of view up to a distance of 3 meters [8]. The Devantech SRF08 can detect up to sixteen distinct echoes at up to 6 meters distance and allows up to sixteen units to be attached to an I2C? bus.

One paper I found achieved 0.25mm resolution, although they were using advanced signal processing methods. ( ) I would guess that a resolution of ~1mm is possible with the standard sensors? Another paper ( ) about a homemade ultrasonic sensor said it got a resolution of +/- 2", and that 1" of distance change corresponds to 148 usec time delay based on the speed of sound. So I would bet (but have no real reason for believing this) that the pre-packaged sensors can detect things within about 20-40 usec which would correspond to a resolution of ~3.5-7mm.

This paper website ( ) talks about ultrasonic ranging issues but unfortunately has very small plots which you can't really see.

Note that we should be careful about the minimum range of the sensors--if there's something with a minimum range of >3-4mm, it probably won't work for practical reasons of attaching it to the robot..

-- MarkCutkosky - 19 Jan 2007

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