Water Flow Controler Project

Projects General Guidance
1

As a short introduction, I have no experience whatsoever in doing a project like I'd like to do. My programming skills are below average. I have no electronics experience, but I can read and ask. So the first thing was reading, a lot of reading and I think I'm up to the task of building a water flow controller.

First I sketched out what I would like the device to do, then looked for possible hardware. For each item I hunted the web to find demo code and clips. The whole is broken down into manageable chunks, starting with the simpler parts and then building up.

There are quite a few questions left open I'd like to have answered before I buy any hardware. The first one am I on the right track? Things missing?

Then there is the question what Arduino to choose? If I get this thing going there are a few more projects to do and what I would really like is automatic (wireless)logging to a separate data server when a device is switched on. Now, this is of later concern but may influence the choice of board. Would the Yun be something to look for right now, or are the "extra's" a distraction?

Water Flow Controller

Settings:
modes:
measure flow rate & volume (default)
flow rate max | real time adjustable
measure flow rate & volume & stop at target volume
set target volume
flow rate max | real time adjustable | set fixed flowrate (&curve?)
start, stop (&reset)
halt, resume

Display:
target volume , total volume since start
target flow rate , flow rate
water temperature , timer(m,s)

Alarm:
5% before set volume target
set flow rate cannot be reached (low - high)

Hardware:
arduino X
LCD, buttons, rotary, ...
solenoid valve (as a fail safe if power drops)
relay (for solenoid)
temperature sensor (really wanted to make a mass flow controller, but this will do)
servo 90°
ball valve
simple flow meter (to be upgraded later)

The Manageable Chunks:
get the thermometer going (1-wire)
get the solenoid valve going
get the flow meter going and calibrated
get the servo going, controlled by a pot
get display going & get a timer/elapsed time going
hook servo up to valve
get setting volume target going
use pot/servo to get a certain flow rate
tie it all together (OOP)
(add PID to control flow rate from pre set (point or curve))
make menu and decent input controls
encase

Possible extensions, logging & phone home

Cheers,

Ingo

2

Perhaps you can tell us what the project is?

Where does the water come from and go to? and why?
How much water is flowing?

...R

3

The controller is to be relative general purpose devise, cold water for small cooling, hot water for extracting, think of a process similar to coffee making or sparging in brewing. For the extraction the amount and flow over a certain time have to be quite exact, hence the temperature measurement (convert volume to mass). I'm aware that the simple flow sensors are not great in accuracy, so once all is functioning it will be replaced by an accurate model.

The water will be mostly hot (80°C) or cold tap water, it can be pumped from a well or a ice water bin. The fluctuation of the input flow from the source is low, that's why I think a PID ain't necessary at first. In the extraction process a constant flow is not the optimal, that is where the PID can be help full. A third source of water is by gravity feed from a tun on a roof.

Water temperature is in the range ~0 to ~ 80°C, but not fluctuating in a wide range, +/-2°C. The required output water flow, for now, is in the range of 0,5 - 10 l/min.

Ingo

4

An Uno is by far the best Arduino to start with as almost all the hardware and software is designed for it.

I suggest you get an Uno and write some short programs to read sensors and control things (for example a cheap servo or a dc motor). You can also build a control system demo just using LEDs as indicators for the external hardware.

The Thread planning and implementing a program may be useful. And there are examples for code for most parts of your project in the Arduini IDE.

...R

5

Thanks,

I'll dive in to it,

Ingo