Probably a very stupid question, but what kind of current could I expect my sensors to draw from the Electron when it’s in Deep Sleep mode? Is it the same as Quiescent Current, or less than that?
@Vitesze, as much as we would like to help you, we are not clairvoyant. We can’t guess what “sensors” you have and how you have them connected. A few more details might help
But shouldnt there be official documentation about it? For plenty of sensors I can find ddocumentation onn their quiescent current, but for the HC-SR04 its simply <2 mA…it matters whether thats 0.5, 1 or 1.99 mA
Anyway, assume a basic setup of an Electron (in Deep sleep mode) powering up one HC-SR04 sensor through a Polulu 5V DC converter. Nothing else.
@Vitesze, your original questions said nothing about the HC-SR04 or the Polulu converter. The total deep sleep current (Ids) for your setup will be:
Ids Total = Ids Electron + Ids Pololu + Ids HC-SR04
Which Pololu converter model are you using?
As for the HC-SR04, the best I could find is the < 2ma spec. Spec sheets are not always very good.
If quiescent current is a major concern, you may want to control power to HC-SR04 and even the Pololu if it dedicated to providing power to just the HC-SR04. You can do this with a couple of mosfet whose gates are biased so as to be turned off by default. This will prevent the mosfets from providing power while the Electron is in deep sleep and its GPIO pins are floating. Some Polulu converters have an enable pin to disable the output power and draw < 100uA.
This type of control will ensure the lowest deep sleep current IMO.
I guess my original question was more about whether sensors would consume the quiescent current, or less than that in deep sleep state. I wondered if there was a difference between the Electron being in stop sleep mode, or deep sleep.
The Polulu would be only powering the HC-SR04. Polulu is U1V10F5. Quiescent current for that should be well below 1mA. Quiescent current is extremely important to me as I’m trying to develop a sensor that lasts as long as possible just off the battery. There’s no good alternatives for the HC-SR04 as all the MaxSonar and URM ones don’t sense anything within 15cm (or draw a very high current). So I’ll look into mosfets some more later. Thanks for the help!
Using this Pololu converter would allow you to shut it down to get sub-100uA power consumption. Then you wouldn’t need a mosfet for the HC-SR04!
Can you use a ToF (Time of Flight) optical sensor instead of ultrasonics?
Oh I see, that would be great! That would work for any ultrasonic sensor then, regardless of model and type?
Optical sensor is not really preferred. I want to use my sensor inside a large dumpster and I’m afraid that over time enough filth will accumulate on the lens to block the signal completely. Ultrasonic could have a similar problem but I feel like they would be less sensitive to it.