Connecting Electrical Components for Outdoors

Using Arduino Project Guidance
1

Hello,
I am currently working on an IOT project for a smart irrigation system which involves having my mcu powered by solar and located in the outdoors.

Additionally, the wiring for my project will include receiving signals from moisture sensors and sending power to a solenoid valve. For these tasks I will need to send wiring through an electrical box like the one pictured and through the environment and ground(for moisture sensors).

I have little experience with outdoors wiring and so need advice on how one should or you would go about connecting these materials(for example waterproofing the connections and electrical box openings and what wires to use for connecting at further distances).

I really appreciate any help immensely and I also pictured some of the components of my project to give visual of what I have. For what I have planned, inside the box would be the Arduino uno, 5v solar manager, and a lithium battery, as well as a pcb for additional circuit needs. The solar panels would be connected in parallel and run with a wire into the box. I am not the most experience so any advice even on the planning would be helpful as well.

electrical_box
electrical_box1920×2560 630 KB

2

Search on cable gland. Here is the first result I found.

EDIT:
Adafruit has some common sizes.

3

  • Is there need to have communication from the box to inside the house ?
    Perhaps use an ESP32 WIFI controller.

  • Google water proof wire connectors.

  • Suggest you use an Arduino Pro Mini instead of the UNO.
    Solder wire connections to the controller.

  • Only use capacitive moisture sensors.

  • Investigate low power sleep modes for the Arduino.

  • The solar cells should be in a moisture proof mount.

  • How much current does the solenoid need.

4

Keep it simple, put all wire holes on the bottom and seal with RTV. Cheap and works very well.

5

Only use plastic boxes and conduit.
Even the best moisture sensors will not work for very long.
There are literally hundreds or thousands of this project out there and here in the Project Hub. Learn freo those who went before you.

6

I assume your box is NEMA 6 or 6P rated for the environment. You want weatherproof through the bulkhead connectors. In the past I have used Pave Technology Feedthroughs. That or using some RTV or similar you can roll your own.

Ron

7

Thank you for your assistance.
I will do the tips you mentioned on the water proof connectors and the mini as well as research the advice you have given.

For the controller itself, I don't think I can use a WIFI controller due to the project occurring at a community garden in a local park so it is not close to my house. The solenoid valve I plan to order I believe needs 4.5 volts for a working voltage which I understand to be a maximum. I might alter the exact model however as I want to further research it.

Thank you for your help by the way, I appreciate it a lot.

8
  • What current does it require ? How long will it need to run for per interval ?

Community Garden :thinking: :roll_eyes: what will you do about vandalism ?

9

I'm not sure those boxes are really that water tight. Pressure on the gasket and or variations in molding may cause leakage.

For connectors, you might be able to find so surplus military connectors.

You should put some desiccant packs in your housing when finally closing. You could also put clear packing around the housing where the cover separates from the body.

If you chose to seal individual wires through holes, be aware that moisture will travel through stranded wire (between the strands) if both ends are not sealed.

10

MY experience for my irrigation system installed for 17 years with no problems.

  1. Use outdoor rated extension cord wire. Cut the ends off. Cheap and reliable.
  2. Do not use desiccant in an enclosure, but ventilate the box top and bottom with vents that let air in and out, but keep bug out.
  3. Any wire to wire connections out of the boxes, use correct wire nuts on the wire and stretchy rubber tape, then plastic electrical tape on each connection.
  4. Any underground must be in plastic conduit from box to box and seal with proper cement.
11

I did not see any current specifications on the listing for the valve, but for the interval length it would probably be around 15 minutes maximum.

For vandalism I don't really have much in mind. I volunteer at the garden and it is a pretty well ordered place with this project being a prototype of sorts. I suppose I could put a warning but I don't think anyone would vandalize the project.

This is the valve I was considering just to show Incase you can find information I might have missed: Amazon.com: Solenoid Valve, DC 4.5V 1/2" Water Pulse Electromagnetic Valve Brass Solenoid Valve for Liquid Water, Air and : Industrial & Scientific

12

Thank you for your advice.

Would the ventilation you mentioned work in a humid environment. Also when you mentioned sealing with cement for boxes, would simple wiring to sensors underground need cement sealing or could I run it with plastic conduits underground and then straight to a central box. Would that situation need two or multiple boxes?
I don't know alot on the underground wiring so information on that is really helpful.

13

Paul,

Did you have a pcb in your system? If so did you use some sort of conformal coating?

14

Yes, pcb and other components. Live in dry Central Oregon desert. Very low humidity! More snow than rain in Winter. The problem with moisture is condensation from high humidity and rapid temperature changes. In other parts of the country, desiccant packages need to be changed often.

15

You use plastic conduit underground so you can replace the wires without digging up the whole thing when problems occur. Check with your local hardware/building supply business and they will show you about the plastic conduit for use under ground. And yes, you need to use the proper cement to seal all the connections.