Voltage question

[Massi]

Hello all,
i have a wind sensor (TX23 from lacrosse) connected to my py, and OFTEN it works. I mean than when raspi boots up, it do not work, if i disconnect and reconnect the cable, it starts working and never stops.
This happens only when i take off the power to the raspi, if i restart it the sensor always works.
It is commonly powered by 2 AAA batteries (3V). I powered it up with 3,3V from Raspi.

Now, since it's an annoyin problem, i powered it with a couple of batteries (common ground with raspi, obviously).
Magically, now it always work.

So i thought that maybe the way power line goes up can create the problem. But what if i'd like to avoid batterie? what can i use?
Or better, what about something like this

Code: Select all

raspi 3,3V
------------
      |
      |
big resistor, let's say 1M
      |
      |
Sensor VCC and batteries +
      |
      |
-------------
common ground

In my idea, this is giving solid minimum 3V to the sensor, and current on the resistor should be very low. But with this circuit, who is powering the sensor?
Can this work?

thanks a lot

[Laurens-wuyts]

Same problem?
http://www.raspberrypi.org/forums/viewt ... 91&t=90191

Laurens

[Massi]

Same problem?
http://www.raspberrypi.org/forums/viewt ... 91&t=90191

Laurens

Yes!
But since:
- i tried changing cable length (no result),
- no other sensor has problem with power (i also added other things)
- i tried pullups in every section of the circuit
- i'd like to avoid active components in this circuit (like an arduito controller)

i was just curious if a power circuit with 2 voltage generator (raspi and batteries) can work..


(btw congrats for your memory, i neither remember i had posted my problem with all those details lol)