How not to connect a hosepipe to the internet

 “Fill the hose with cables and plug it in”, said a helpful Facebook commenter. I thanked him, and laughed, but mostly out of fear he was trying to kill me.

“What you need,” said another friend, “is an app.”

“An app?”

“An app.”

I considered this. I don't know a lot about apps. The only one I've tried is the iPint. It's impressive but ultimately leaves you thirsty.

“Apps can't interface with anything that actually exists, like water or compost. If I tried, my iPhone would get wet and stop working. Besides, I don't have an iPhone.”

“You can control your central heating with an app. Can't you do the same thing with hosepipes?”

“I can't connect a hosepipe to the central heating,” I protested. “It might boil the plants.”

So I asked Jonathon, who works at a desk and has IT skills.

“Hmm,” said Jonathon, and went for some tea.

Then half an hour later, he had an idea.

“You can buy socket adaptors that can be controlled via wifi. I was thinking of getting one, so I can turn my kettle on without getting out of bed. If you plug a pump into that, and hook it up to your water butt, you could turn on the pump from anywhere in the world.”

I felt we were getting somewhere. That would work. That would come in at under £100, and would definitely work. Yes.

Ah. No! No – wait.

Like a lot of projects, this one comes with constraints, which only really become clear when you run into a problem. One of my constraints rules out a lot of possible systems.

I can't run any wires between the house and the garden.

This really arises because I live in a rental, and I'm reluctant to drill any holes in the walls. It's also because I'm hoping one day to adapt the system to work on my allotment, where there is definitely no power supply available.

I expressed my concerns. "Never mind," said Jonathon. "I'd much rather be talking about hosepipes than doing my actual job." He pointed me in the direction of Derrick, who is some sort of IT expert. (Derrick isn't his real name, but I will have to call him Derrick, because when we were introduced I wasn't paying attention.)

“A Raspberry Pi,” said Derrick, with some authority. “What you need is a Raspberry Pi.”