Check out the new toy I purchased for only $0.99 + $10s/h on ebay (retailed for $300+).
This sensor is supposed to be used to monitor fuel/water/waste tanks in yachts. I am going to use it to measure the liquid level of my new HLT.
The bottom of the unit has the ultrasonic head which sends out a series of pulses then listens for the pulses to return after bouncing off the liquid. It measures the time between the pulses to determine distance, and therefore liquid level. The sensor performs all the math and temperature correction.
The wood block is a simple test fixture I put together to see if the sensor actually functions... I found it works perfectly!!
As the liquid rises from empty to full the sensor outputs current from 4 to 20mA. I put a 250ohm resistor in series with the output and measure the voltage across it. When my HLT is empty it measures 1V and when it is full I measure 5V. Couldn't be easier to interface to a microcontroller. I plan to mount it to a pot lid that I haven't purchased yet. Best $11 ever.
Secondaries: Lakefront India Brown Ale
On Tap 1: Rootbeer, On Tap 2: NB White ouse Honey Ale, On Tap 3: Nitrogen, On Tap 4: Air, On Tap 5: Air
On Deck: DIPA, Imp Stout, Porter, Wheat, Black IPA
"No sense having empty carboys around when full ones take up just as much space. " - Me