I am looking for a depth measurement that can ideally measure to less than 10mm resolution. Measurements would ideally start at 0 and extend to 2000mm.
It is for ranging to a snow surface in an exposed alpine environment. Needs to survive temperatures down below -15 Celcius and needs to be waterproof.
So far i can see the most suitable candidates as being:
XL-MaxSonar - WRL1 (MB7066)
-what is the difference between MB7066 and MB7076 ?
Senix ToughSonic/PC Distance Sensor TS-301 Series
Can you please suggest alternatives?
Also would these sonars pick up the snow surface?
Are there alternatives that would better pick up the snow sirface, e.g. laser range finder or perhaps other methods that i am unfamiliar with??
You will need to experiment, not sure if certain types of snow are too porous to effectively work with ultrasonic rangefinders. One common practice would be to use a combination of ultrasonic and light based sensors, such as a SHARP infrared rangefinder, to compensate for each other’s weaknesses.
An ultrasonic rangefinder should be theoretically able to detect snow and measure its distance from it. Nevertheless, it is important to keep in mind that snow can greatly dampen sound. Only experimentation can tell for sure if a sonar is adequate for your needs.
The main difference between the MB7066 and MB7076 is that they offer a PWM output for the former, and an analog output for the latter (as shown in page 2 of the datasheet under “Pin 2”).
The WR MaxSonar line of Maxbotix products is rated IP67, meaning that they are dust tight and immersible up to 1m. For your needs the XL-MaxSonar-WR1 rangefinder should be appropriate.
The Senix sensors are rated IP68, meaning they are also dust tight but immersible beyond 1m.
Besides a laser rangefinder, the ultrasonic rangefinders seem to be the most appropriate for your application.
