3.3v pins

[Lazzz]

I am using both 3.3v GPIO pins on my Pi4 - 1 with BMP280 sensor & the other (17) with DS18B20 temp sensors.

I need to use another relay on a 3.3v pin.

Is it possible to double up the BMP180 & the DS18B20 sensors on one pin??

Is there any other way I can use this new relay or do I get rid of the BMP280??

Both 5v pins are being used as well.

TIA

[SCarns]

how about something like this?

https://www.amazon.com/GeeekPi-Connector...440&sr=8-4

[PaddyB]

Pins 1 & 17 are already joined internally so should be no problem sharing externally. Think 500mA available apart from early models.

[burgoynebc@netscape.net]

I'd be interested in hearing how you make out with the dallas sensors. I setup about 10 on one wire with pullup resistors etc. I got good results with single units but when multiple units were wired in, I got sensors that would not read over ?135F. I never could figure out why and gave up on them
Richard
SV Zolanda

[Techstyle]

I'd be interested in hearing how you make out with the dallas sensors. I setup about 10 on one wire with pullup resistors etc. I got good results with single units but when multiple units were wired in, I got sensors that would not read over ?135F. I never could figure out why and gave up on them
Richard
SV Zolanda

I have 5 attached, but only 4 seem to show up.  somebody on the Signal K slack channel said that you get much better results with real Dallas semiconductor made sensors, rather than the nice looking generic packaged ones you find on Amazon.  I have some of both but only have the Amazon ones fitted at the moment.  I am thinking about swapping over and seeing if that is true

[holgerw]

use an relay here , no, never" but for signaling the level to some transistors in between - you may use lots of relays, but not directly! the 3.3 Voltage is only for signaling - never use it for power delivering, it only an little poor chip there. realys need an amplifie aka transistor and mostly use 12 v to react.

try an little googleing on interfaces for relays.

holgefr

[Lazzz]

use an relay here , no, never" but for signaling the level to some transistors in between - you may use lots of relays, but not directly! the 3.3 Voltage is only for signaling - never use it for power delivering, it only an little poor chip there. realys need an amplifie aka transistor  and mostly use 12 v to react.

try an little googleing on interfaces for relays.

holgefr

This is what I want to use - the 3.3v is only for signaling: 5V Single Channel Relay Module 10A Australia (core-electronics.com.au)
Controlling a Solenoid with Raspberry Pi and a Relay - Tutorial Australia (core-electronics.com.au)


I have 5 DS18B20 sensors running all accurate with no problems.

Thanks for your help everyone

[holgerw]

This is what I want to use - the 3.3v is only for signaling: 5V Single Channel Relay Module 10A Australia (core-electronics.com.au)
Controlling a Solenoid with Raspberry Pi and a Relay - Tutorial Australia (core-electronics.com.au)


I have 5 DS18B20 sensors running all accurate with no problems.

Thanks for your help everyone

They should be okay, can even work with 3.3 Volt from the pi. For the Guy with 10 or more OneWire-Sensors, first try for me is to go down with the PullUp-Resistor, this should replaced with 2k2 or even 1k Ohms.