Sam Selby

A Lockdown Project – Making An Automatic Poly Tunnel

Automatic Poly Tunnel – A Network Engineer’s Lockdown Project

An automatic what?

I’ll start at the beginning; you remember when the first lockdown kicked off? Well I had big plans for the summer of 2020 – Taking my KTM for a dirt-biking, wild-camping, road-tripping adventure to the Arctic Circle by way of the Trans Euro Trail through Sweden and Norway. It quickly became obvious that this particular dream was not going to be a reality, but with a chunk of holiday booked I instead turned my attention to another aspiration: build a poly tunnel to increase our veg growing capabilities and automate it as much as possible (I hear you… busman’s holiday?).

What can you automate in a plastic tent full of plants, how techie does that really get? Well unfortunately I can’t figure out how to set the weeding on auto, but two important things were in my sights: watering and cooling. Poly tunnels can get really hot very quickly, and there’s a time and place for cooking veg – and while it’s growing is not that time, so my plan was to automate the irrigation and open/close the doors based on temperature.

Do you have a greenhouse or poly tunnel? This is how it could benefit you:

  1. Idiot-proofing (you won’t forget to open the doors in the morning)
  2. Laziness
  3. Convenience (you can go away for the weekend without bribing a neighbour and hoping they don’t succumb to points 1 or 2)
  4. Maintain a higher and more constant temperature to improve yield (hopefully!)

I was shocked to find that when I went to place my order with First Tunnels (highly recommend) instead of a 4-day lead time they were quoting 7 weeks – “warehouse issues from covid restrictions?” I asked, “nope, we’ve just never had so many orders” came the reply. Blimey, evidently half the country also decided it was time to get growing – if you were one of them then this little project might be just what you need.

I am a self-confessed ‘geek’, of almost anything techie, but I don’t have a background in electronics, and this was my first Python project. In the video, I’ve talked through the way the system works – to be fair the temperature-controlled door automation was pretty simple, the Python libraries supplied with the relay boards are super-easy to implement, even for a n00b. What took a little longer was building a web-app for manual controls and settings, and catering for all the inventive ways people can mess it up with a few buttons and sliders.

Check out the video (below) for details and a demo – if you like what you see and you want to try this or automate anything using a sensor and relays, then my scripts are free to use via open source here. The technology used is:

  • Raspberry Pi 4 (running Rasbian)
  • Temperature sensor
  • 4relay hat (so I can switch 240v to turn on a 12v transformer on demand)
  • 8relay hat (you could do it with just this if running from a solar panel / battery)
  • Python3/MySQL
  • PHP/MySQL/HTML/javascript on Apache for the web-app

One of my more entrepreneurial friends was telling me to package it as a kit and sell it, but really, I think every setup will be so bespoke that it’s not practical, plus I like to share! The mechanics around the doors are a puzzle for each different scenario, with no right answer, but there’s fun to be had in ironing out the peculiarities. My system has been in place for over a month of extended beta testing and so far, it’s stable and effective… tempted?

If you decide to try it and you want to drop me a line I’ll happily provide a little advice if I can.

Nick Franklin, Senior Network Engineer

Photo by Markus Spiske on Unsplash

Lessons from Big Tech

Lessons from Big Tech

Our recent experience with the Best Companies Index has provided lots of interesting data about how we could make Delt a better place to work. It got me thinking and subsequently researching some of the different things that factor into a ‘good’ workplace.

Looking at one big list of best employers is very interesting:

They are all pretty large companies, the smallest on the list having around 1,500 employees, but most being in the tens of thousands (or more).

Of the top ten list I’m looking at, one is a bank you probably haven’t heard of, one is a hospitality company, one a research company and the other seven are all tech companies. The names won’t surprise you: Microsoft, Google, Apple and so on.

I wanted to know what other things these ‘best’ companies had in common. One of them is that all have ex-employees who think they are terrible. Reading some of the negative reviews on Glassdoor makes you wonder why anyone would choose to work there.

Some are profitable, some are not. Some pay people really well, some don’t. Some have a long hours culture, some don’t. Then I found something that seemed common. They all had higher than average staff turnover. Tenure in the majority of these ‘good’ organisations was around 2.5 years. At one point, Apple had a near 40% annual attrition rate, which compares rather unfavourably to the 15% average you find in the private sector.

This started me thinking. What if being a good employer isn’t just about the employer but is just as much about the employee. People clearly aren’t staying for the long term at these companies, but are moving on.. They don’t appear to be leaving because they are unhappy. Are the sort of people likely to be attracted to fast paced jobs in the tech sector, who have rapidly moving careers, that change jobs on a regular basis… Are such people simply likely to be happier and more engaged at work than somebody who is looking for a long tenure in a slower paced environment?

One thing is certain – your ability to have a really good place to work is not simply about what you do, it’s also about who you hire and of course, who you don’t.

Giles Letheren, Chief Executive Officer

Photo by Diego PH on Unsplash

Kim Brown – Non-Executive Chair

Kim Brown – Non Executive Director

Kim has more than 20 years’ experience in the public sector, including working in three London Boroughs prior to joining Plymouth City Council as the Service Director for HR & Organisational Development.

Kim is experienced in driving and delivering change, leading and managing high performing teams, building successful operations and relationships with internal and external stakeholders across complex organisations and services.