Reducing noise and Implementing multiplexing system

[arj511]

Problem:
A micro-controller needs to take all of the inputs of 12 digital sensors and 6 analog sensors at 5 minute intervals.
1. The raw output from the sensors are now having a lot of noise that needs to be filtered/conditioned with appropriate hardware/software design

2. The output of the 6 Analog sensors (Flow sensors, TDS sensors, Turbidity sensors) are as follows

a. 2 sensors whose output varies between30-35 Hz

b. 2 sensors whose output varies between 12-24 VDC

c. 2 sensors whose output varies between 100-500mA

You will need to design appropriate amplification system wherever needed
3. Due to the limitations of GPIO pins in the board a multiplexing system should be designed that would enable the controller to read all the inputs.


Details:
Microcontroller: You could take your preferred microcontroller

You are required to design/implement a system that could potentially solve all the problems. A brief write-up of the approach you decided was optimum, your reasoning and most importantly proof (screen-shots, pictures and snippets of simulations, source-code etc.) to validate that you made it work should also be attached along.

Any help would be appreciated!! Im new to electronics

[pebe]

Hello arj511, and welcome.
You say you are new to electronics. Have you had any experience with microcontrollers?

2a refers to an analogue sensor that outputs 30-35Hz. It specifies 'analogue' so I assume it measures amplitude - in which case the range of amplitude needs to be known, and whether it is a sine or a square wave.

It is not necessary to take the multiplex route because a micro like a PIC 16F1507 or 16F1512 can handle all 18 inputs via separate pins, and that makes the hardware simpler. Neither is discrete filtering required because the micro can handle that in software.

[arj511]

The range is as follows:

Input Voltage

5 to12 VDC

Output Signal

Square wave of 5 to 12 Volt amplitude

15 – 17.5 Hz/m/sec

[pebe]

You haven't said whether you have had experience with microcontrollers.
What do you mean by 'Hz/m/sec'?