Raspberry P.I. Connection of a large number of analog and digital sensors

Question

Do it yourself

Tell me how to take readings from many sensors (about 20 pcs.) Using Raspberry PI?

Ideally, I would like to be able to control ports like on Arduino. Maybe there are some expansion boards?

The power of Arduino is not enough for my needs and I wanted to have full-fledged Linux.

Answer 1

I think that the most correct solution would be to connect an additional controller to the RPi - at least the same arduino, to which sensors, etc. are already attached. and already receive data from the controller and process it on the RPi

Answer 2

Maybe then you should follow the path of industrial automation? Connect the RS232 <-> RS485 converter, and then hang as many different modules as you like on the common RS485 bus. What is the "geography" of the distribution of sensors? (close/far from raspberries)

Answer 3

what about sensors? What speed / polling frequency do you need? are interrupts needed? do you need realtime?
and then maybe shift registers on the SPI bus at 8p for 8 lines will suit you?

Answer 4

Connect part of the sensors to Malinka, and part to an external controller such as Arduino.
I now need several UART outputs, which is not on the raspberry. Now I'm making my expansion board based on a microcontroller. You have the same case.

Answer 5

If I needed to upgrade a bunch of digital add-ons to RPi, I won a GPIO expander type MCP230xx. There zv'yazok on і2с і їх you can 8 pieces at one time wink. 128 additional pins go out in a zagal.
The choice of analog sensors is called rich-channel ADC. I've hacked the MCP3208. Spilkuvannya by SPI.
Zvichayno svidkіst splkuvannya will be small, but for example, for tasks such as "intelligent booth" will navit іz reserve.