I'm looking for a recommendation for a simple irrigation project with good build support, I'm competent with the electronics and wiring but almost ignorant of programming.
There are absolutely hords of projects which is why I'm asking rather than going right to the build.
I'm going to be using an Arduino Uno
I want a system pumped from a water barrel posibly to drip feed, with a barrel water level sensor and a simple rain guage rather than soil sensors. I know it will less accurate but it's less complex and doesn't require running wires around the garden. Beyond that I prefer to use a rotary encoder and local display to set the parameters, again just to keep things simple and as far as possible self contained. If an alternative is easier to implement I'll happily do that.
You seem to be in the trap of expecting that there will be some code out there that matches your particular requirements (rain sensor, rotary encoder...). It almost certainly doesn't exist. You will find code that does some of what you want and code that does other parts. You can use these for reference and inspiration, but I would not recommend trying to merge them together like welding two halves of crash damaged cars together. Learn from those examples but write your own code, starting as simple as possible and building up slowly, testing as you go.
Some questions to think about:
How will the project be powered?
What are the requirements of the pump (voltage, current). What's the best way to control it?
What rain sensor do you plan to use? Some are very sensitive and can be triggered by a few drops, which don't provide much water for your garden. Some can measure the total rainfall over a period, but aren't very sensitive to light rain. You may begin to understand why so many of the projects you have seen use soil moisture sensors.
Oh well, now you have bought it, it's better to use it than to waste it! For the next project, think about what type of arduino would be best before you buy one.
Thats a shame, I'd hoped to simply copy an existing project. There seem to be lots published but they are more complex than I need.
Two cycle timers and a ssr will do it if I loose the rain guage.
"Pet feeder" projects usually make something happen twice a day. You understand the special attention needed when combining water and electricity. Here is one simple pet feeder to examine or use the code. It does nothing more than wait for two pre-programmed times of day, then actuates a servo. There are controllable water valves "out there" and some have been used on this forum. Have fun. Make it happen.
I just need to pump from a barrel, I have a submersable pump in hand.
The minimum I want is timed water flow. If there is rain then a rain guage should interupt the cycle.
Don't let them bs you. Search for "plant watering" and you'll find lots.
Get you hardware and sensors working electrically, then worry about code.
Flow chart how you want it to work. Doesn’t have to formal, just block out what does what and what causes things to change.
No problem.
Sounds like you have access to a 3d printer. That will help -- a LOT.
To build anything with arduinos you need terminal shields (~$15) so you can screw down the wiring. You also need a power disturbution board (~$15 parts and under an hour to fab, requires soldering) to power everything.
Uno's don't have a lot of memory, I prefer the Mega.
I have lots of 3d print files for mounts and cable shrouds and the like.
code is trivial. Too dry (moisture sensor not met), pump on (control SSR for control of big pumps if req'd). tank empty (float valve at bottom), sound alarm (direct drive) & refill, etc. Nice LCD display to show status or "traffic light" (R/Y/G) stick:
I order most everything thru Walmart or Jameco.com (5v power supplies), because they warranty everything, no questions. Have never gotten doa parts.
Cables need shrouds to keep the duponts aligned, give pin 1 mark, give labelling area, and improve retention. I have .stl files on cults3d.com but latest versions I can send if needed.
It has everything to do with the drip irrigation the OP wants to develop. What do you think makes water drip in a drip irrigation system? The amount of drip is based on the size of the hole in the dripper and the water pressure. No pressure, no drip, only gravity might make the water trickle out.