Rasberry Pi 2 analog inputs

Question

I am a newbie with the Raspberry Pi.

I want to measure temperature from 16 sensors. Is it possible to have 16 analog inputs?

If not what controller should I use, I need something with web server.

Answer 1

You can use the Raspberry Pi for the webserver. You have a variety of programming lanugauges you could use, like Python, C/C++ even C# (in Linux using Mono) or Windows IoT.

It would be allot easier if you could use I²C - Which supports connecting allot of sensors (various types) typically using 4 wires (2 power + 2 RX/TX for bidirectional communication) (or 3 wires if using a leech circuit) to the Raspberry Pi's I²C

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You can also get sensors using the 1 Wire Protocol, like the DS18B20. This only requires 3 wires (2 power - 1 RX) since all we are doing is reading data and used GPIO PIN 7. You then need to enable the device tree for 1-wire in /boot/config.txt by adding dtoverlay=w1-gpio and rebooting the Raspberry Pi. You can also mix various sensors using 1-wire

^{* A nice tutorial and source of image}

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But if you have no choice but to use Analogue you could get a 16 channel multiplexer and connect that using a few digital pins to the Raspberry Pi. You can find those at any popular electronics shops and are pretty cheap, you shouldn't need to pay more than 5USD/3GBP for one of these. You still need to convert the output from the multiplexer SNG to digital though.

The multiplexer works by setting the digital pin combination, to set the Analogue channel you would like to measure. So you cant have real-time measure of all 16 sensors at once, but you can switch between them pretty fast anyway and get possibly all 16 reading within 1 second, maybe faster.