Meet Jeff Geerling

Andrew Gregory of HackSpace magazine sat down with the one and only Jeff Geerling to chat about the wholesome corner of the internet he created.

jeff in a blue anti static jacket pointing at raspberry pi awards inside the sony factory
Jeff exploring the Sony factory where Raspberry Pis are baked

If you want to cut through the buzzwords and find out what tech actually does, you could do a lot worse than listen to Jeff Geerling. He’s built an utterly wholesome corner of the internet in which he explains, demonstrates, and demystifies the latest thing that everybody else pretends to know about. Linux, single-board computers, open source, developer tools, home automation – Jeff does the lot, and he wants to teach you how to do it, too. We thought we’d talk to him about what he’s been getting up to with his new Raspberry Pi 5.

HackSpace:  Morning Jeff! You’ve done loads of Pi projects over the last couple of years. What do you still have running at the moment?

Jeff Geerling:  Things that are practical, really. I have Pis running all of my home network stuff, all the home lab-type things; I have a Pi running internet monitoring, so I can keep my ISP honest. I have a Pi running my VPN. 

I have no cloud services for my light bulbs, or for my HVAC or anything. It’s all running through Pis. I don’t have any cloud account tie-in. If the internet goes down here, the only thing is I can’t access it remotely, but everything’s still running. I love the privacy aspects of it. And I love the ability to learn new things through it – industrial automations, and controls, and APIs with these different systems. 

I think one of the things that fascinates me the most is all these different IOT devices. Before I knew much about Pis and microcontrollers, I always thought IoT was magic. And then you open one of these up, and you just see a little microcontroller inside. It might just be an ESP board, or a Pico, or something else. But I know that I could hack it, and that opens up a new world. You could build one of those on your own to just about the same quality; you can’t get injection-moulded plastic, but everything else you can do on your own, and 3D printing has made it so that enclosures can be so much nicer. It’s just cool to see. It’s like taking down the wall of magic that you thought existed between really cool products and your own abilities. 

jeff wearing a mask and soldering towards the camera
Jeff describes himself as an electronics beginner; something tells us he’s being modest

The projects that I do are typically rehashes of what other people have done; I might make the documentation a little better or I might package it up a little nicer. But really, I would say that I’m beginner-level electronics and beginner-level microcontrollers. I just have the ability to relate what I’m doing a little better than a lot of people who are experts at it.

A year or two ago, I talked to [Linux YouTuber] NetworkChuck about recording a podcast episode. He does a lot of stuff with Raspberry Pis, too, with red hat hacking and black hat stuff. And, you know, fun things. So we recorded the podcast. And it never went up because one of the microphones was messed up, and it sounded terrible. I didn’t hear from him for a while, and then on 01 March this year, he’s just like, ‘Hey, Jeff, do you want to work with me on a Mr. Beast project? At like, 9 am, right now?’ I had no travel planned and no deadlines, so I said yes. 

And that was terrible, but also awesome. So many people who make things, especially if you make it for production use, want to make sure it actually works. So there’s a deadline attached to it. There are problems; there are always challenges, things you didn’t even think about. And that’s what happened on the Mr. Beast project. But that’s also kind of the addiction that drives us forward. Because while I would say I don’t want to ever do that again, I also say that was a fun experience. And getting to meet all the people there. And all of us going through that at the same time, solving all the challenges. It’s a weird kind of addiction that we have, I think, building software, building hardware, and working on something so big as well. 

Any time we solved a problem with a five-minute fix, the sheer number of computers we were using turned that into a multiple-hour fix. 

jeff in a red t shirt holding a bowling ball
Testing hardware by dropping a bowling ball on to it. Always wear eye protection!

HS:  Why Raspberry Pi? What’s so good about it?

JG:  Raspberry Pi devotes a lot of time to testing and to making sure manufacturing is better. And manufacturing in the UK is a pretty cool thing. How many computer companies manufacture things in their home country – there’s not many, and Raspberry Pi does on a huge scale. So there’s a lot of those things that some people don’t assign value to – not just the bits and the little circuits on the board and all that. 

Open source is another balance that Raspberry Pi has to offer. There’s the Broadcom chip [which isn’t open-source] versus you’re building the operating system based on Debian, which is like one of the most open-source Linux distributions. And it’s a weird balance. In the hardware world, it seems like there’s a lot less open source, because if you put out an open-source design and someone else makes it, all of a sudden you have zero revenue. Versus software, there’s sales and support and services, and there’s a lot more revenue opportunities that can’t just be immediately consumed by another company. Although, recently we’ve seen Amazon doing that sometimes, and leading to licences like the BSL, which is not really open-source.

jeff in a red shirt looking into the camera holding a pi cluster next to his face
Jeff’s fascinated by factories. And he loves open source software and hardware

HS:  I’ve heard of the BSD licence, but not BSL.

JG:  Most open-source licences don’t care if you’re a government or a spy or a bad person or a good person – it’s free. It’s unencumbered. But the BSL imposes a restriction: if you’re a big business, you can’t use it. Philosophically I can understand that stance, but don’t call it

open source: call it ‘source available’ or, you know, ‘maker friendly’. But on the flip side, there’s so many companies that start as a maker, somebody who designs a little thing, that thing becomes popular, and all of a sudden you’re a big business and your licence is void, just because you hit a revenue number. And it doesn’t matter if it’s 50 bucks or $5 billion, it’s a restriction and it’s a philosophical thing that’s not compatible with my understanding of the term ‘open source’. 

I think Raspberry Pi offers a little bit of a different take on it. Early on, a lot of the hardware was super locked down and there weren’t datasheets. And one by one, they start making things better at release. So, you know, my hope is that someday we could get more open firmware and stuff for the Broadcom chips. I don’t know if that’ll ever happen. But it would be cool. Unlike many companies, where they start out open source and then start closing things, Raspberry Pi has always gotten better, even if it’s not perfect. 

jeff crouched next to a table with a massive pi cluster on it
The Petabyte Pi: a Raspberry Pi with 1024 terabytes of storage

HS:  Hopefully people will like the new power button. 

JG: For me, the power button on the Pi 5 is the most appreciated new feature. It’s just so handy. Like, if I’m running a Raspberry Pi headless, with no keyboard, I can just do a quick shut down. I mean, I put power buttons on GPIO before, but it’s cumbersome. This is nice to have it on the board. 

HS:  And have you looked into the dual camera possibilities? 

JG:  So machine vision has gotten really interesting in the past year, to the point where there are open-source tools to do so many things that used to require tons of expensive I/O. You can do stereo camera depth vision with all open-source tools, and [I’m] hoping to use Google Coral TPU to do some of this stuff. 

Again, it breaks down that barrier between you and the magic. You pick up an iPhone 15 and it can do depth mapping with whatever that sensor is. And you’re like, man, I’ll never be able to do that. 

And then you get a Pi 5 with Wi-Fi and two cameras, and you’re like, oh, I can plug these open-source libraries together. And we get this – it might not be as high resolution, and it might not be 60 frames per second, but you could do depth mapping and 3D stuff with a little board, and everything’s under 200 bucks, all in, including power supplies and everything. That’s a big difference. 

When I was a kid, you could go to RadioShack and buy an electronics hobbyist kit. And that’s how I learned the basics of resistors and all that. You put them together with little spring contacts, and it was really fun. And you could make buzzers and radios and all kinds of stuff – they don’t really exist anymore. All those hobbies that were big when I was a kid, a lot of them are superseded just by how amazing the technology we have today is. But the Raspberry Pi brings that back.

jeff geerling in a shirt in front of a regency period looking building

What’s funny is that the Raspberry Pi is actually better at IoT stuff than most IoT companies. Mostly because of the open source philosophy. If we all work together, all these individuals around the world can write plug-ins and do stuff where you can put home assistant at your house. And you can interact with any light bulb, any doorbell, any camera, any washing-machine controller. Whereas if you get Philips, you get the Philips stuff and if you get Sony, you get the Sony stuff. 

It’s like the tool world: I use DEWALT mostly, because the first tool I bought was a DEWALT. So you gotta use the DEWALT battery, and then you’re like, well, I could buy this cheaper tool, it’s better. But then it won’t work with my battery. So now I have something like 25 DEWALT tools. I think that’s dumb. It’s ridiculous. And that’s how IoT people want to be: you have the smart hub from this company, and you buy all their stuff. But we’ve already seen companies fail, and then all of your smart stuff becomes dumb. And it’s worse than dumb because you can’t even turn on a light bulb, you know – their server goes down and your lights turn off. 

This is an area where instead of just seeing behind the curtain how it’s done, you can do it better. That’s one thing that I love about the Raspberry Pi ecosystem and the open-source ecosystem together.

HS:  A slightly less practical, though no less awesome build of yours is the Pi cluster. Just one question: why? 

JG:  For me, it’s fun. You get something out of it when you’re doing all this work on a cluster. And the first time you see all the nodes come up together, that’s kind of magic. And then also seeing the fact that, like, you can actually program things to scale. It’s useful for a job, especially if you’re gonna build software for the web. 

It was a springboard for learning. And for a lot of us, we love that. We love hacking with things, and a Pi cluster is just a fun thing to do it. It also has the side benefit of being able to develop skills that might be incredibly useful. There are still a lot of companies that will pay good money for Kubernetes developers, and a lot of people have learned Kubernetes on Raspberry Pi. The shortage really built into that. And a lot of people started using small PCs that they got on eBay, which is perfectly fine. I think that’s awesome. The hard thing was, like, the reason the Pi was great was because it’s a $35 computer – now a $60 computer – but you can still get the Pi 4, and hopefully there’ll be more available now that Pi 5 has been announced. But it was a quick way to get into that whole ecosystem of learning. And, you know, it’s not necessary at all for a home lab. But it’s fun. 

jeff kneeling on gravel in front of a massive folded out solar panel

And it translated into me getting a better job and doing consulting, which also helped me with that opportunity that I got in the pandemic: I was consulting and making extra money from doing all the work I was doing on Pis, learning clustering, because the clustering skills got me a better-paying job. And it gave me the opportunity to save up some money over the next year. I went to full-time YouTube in 2021, so maybe the Pi cluster was the reason I got into it. 

I did my first Pi cluster in 2016. And I had a cluster running from 2016 to 2020 24/7 at my house, and I think had something like two hours of downtime in that time period. 

HS:  You said that you’re not a hardware guy. Does that mean that you have a background in software? 

JG:  I started off doing web design. The first ever project I did was helping a radio station. They just transitioned to computers instead of CDs for their music playback, and in their system it had a file that would write to with the current song. My dad had the idea of taking this data and putting the song name on the website, so people could be listening, go to the website, on their laptop, or in an office, back then people did not have smartphones. It was ahead of its time. So I built a little interface that had, like, a car radio with the song title in it in a little, I think it was in Courier font or something, because there were only ten or so fonts that you could use back then. It worked for five or six years, until they got a real website. But, that was my first-ever project. 

I learned electronics from my dad, who’s a radio engineer. And I, you know, I soldered together an FM radio. I still have the voltmeter that I soldered together when I was, like, eight years old or something. It still works, and I keep using it, even though it’s not as accurate as it could be. And I’m excited to do more of that since the Pico came out. I’ve done some more projects: I built a garage door sensor thing, and I’m working on some software for the Pimoroni Galactic Unicorn to write some stuff on the wall. And now I have a new office that I’m gonna go into. So there’s a lot of opportunities to build stuff for that.

HS:  That’s a majestic piece of kit.

JG:  Yeah. And they put in little things like a button. You know, it’s nice to have a button here – now you can do, like, modes for the display. And you can even make a little game on the LEDs matrix. That’s the other thing that I love about the Pi ecosystem: Raspberry Pi works directly with some of these companies to make things better for everyone. And these companies work back with them. It’s a relationship that has been built up over the course of the past decade. It’s bearing more fruit with the Pico, and I think the Pi 5 will drive some of that, too. I’m really excited to see what people come up with with HATs for the Pi 5 with PCI Express. If anybody comes out with a dual 2.5 gigabit network cat, I’m gonna buy that thing the second I see it.

HackSpace magazine issue 72 out NOW!

Each month, HackSpace magazine brings you the best projects, tips, tricks and tutorials from the makersphere. You can get HackSpace from the Raspberry Pi Press online store or your local newsagents.

Hackspace magazine 72 cover

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