Hi Sam,
Looks like we got this one sorted via the email address on our contact page, but I’d like to add to this thread some info about which to pick:
Hi Folks.
I’m planning to use this as a water tank level sensor and I see there’s a few options for reading this sensor. What’s the recommended mode for a Pico?
Cheers.
Mark
Hi Mark,
Most of the modes of this sensor should work with the Pico. I would suggest using mode 0 mainly because that’s the default mode and therefore the fastest to get up and running.
A Pico should have no trouble receiving the PWM output from this mode and soldering resistors onto the board seems like an unnecessary complication given the default mode should work just as well.
Hope this helps!
Well that took all of 5 minutes to get the sensor working in Mode 0 on the Pico W. A few quick and dirty test measurements seem good.
What I need now is a Fritzing file…
Hey @Mark285907,
It’s good to hear this sensor is working out for you!
It doesn’t look like the manufacturer provides a Fritzing file for this product. Be sure to let us know if you manage to find or make one!
Just wondering if there’s any real world info on the current this thing draws?
The device spec states a static current of 8mA and a working current of 40mA.
Operating in mode 0 I see (using an AT085) a flat 80mA with maybe an additional 10mA when the sensor reads. The pico is in sleep mode 14 minutes out of 15 and only reads the sensor once each 15 minutes.
Hey @Mark285907,
I wasn’t able to find any real-world measurements for the current draw of this module. Mode 0 may use more current, though the values you’re seeing seem significantly higher than the specs.
Do you have any photos or details of how you measured the current?
Thanks Ryan.
The RW Tank project consists of a:
For testing the load I power the device through the USB-C port of the charger module via the AT085.
While the battery is charging the AT085 shows 4.87v, 0.58A, 2.9w. Once charged the AT085 shows 4.98v, 0.08A, 0.39w. Disconnecting the battery has no effect on this minimum load.
The LED on the SEN0208 comes on with each read, which triggers each 15 minutes. I expect it to be idle the rest of the time.
For comparison I’ve done the same load check on my weather station (Pico W, Adafruit charger and gauge, etc) and the AT085 shows a load of 0.01A once the battery is charged.
Hey @Mark285907,
When you measure through the USB‑C on the charger, the AT085 is seeing the current draw of the entire setup (charger, fuel gauge, Pico, and SEN0208), not just the sensor. That’s why there’s still a load even with the battery removed.
It’d be worth checking the Pico W configuration, in your weather station build Wi‑Fi or other peripherals may be disabled during sleep, while on the tank project they could still be active. That difference alone could explain the higher idle current you’re observing.
I find this product (I have the v3.0 version) unreliable when operating on 3.3v from the Pico’s 3v3 pin. Seems to work fine at 5v in testing when powered from VBUS but of course that’s no use when the Pico is powered from a Li-po battery.
Hi @Mark285907 ,
Thanks for following up with this forum thread! Were you able to figure out the cause of this unreliable behaviour when powered through the 3.3V pin on the Pico? From your earlier posts, it seems like this was looking like it would be an issue with the amount of current the sensor was drawing.
It would be useful to know more about this one so we can figure out if this sensor struggles with any 3.3V power source or if it is specifically the Pico that it has trouble working with.
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