Designing the perfect case and cooling for Raspberry Pi 5

As with other videos, this is a machine transcription that has been reviewed by a human. Let us know in the comments if you spot anything that’s way off the mark.

Eben 0:08: Industrial design: we’ve done some more of it. We’ve been doing it for a while; how long have we been doing that sort of thing?

Gordon 0:13: I know! What even is it? Cause like, you know, we just made it —

Eben 0:17: We just don’t know!

Gordon 0:17: We made it up as we went along, to be honest. Why don’t you tell us what industrial design is?

John 0:22: It’s been ten years, pretty much, since the first case design that we did. So that was a range of concepts for the very first case that went into manufacture. And then that really kind of set the scene for all of the peripheral products we’ve done in terms of industrial design. So industrial design being, I guess, how the peripheral products and accessories we do look, but also how they function for the user. So yeah, it’s been great to be involved in. We’ve got a good family of products now that have come out, and some new ones to talk to you [about].

Eben 0:56: But you weren’t with us at first, right? You were somewhere else.

John 0:58: Yeah. So I worked for Kinneir Dufort. They’re a partner of ours now. I was an industrial designer there for nine years. And I remember the moment the first brief landed on my desk to design the Raspberry Pi case. And, yeah, it grew on me the importance of that, and [I] really got stuck in and, yeah, I think we produced quite a lot of designs in that first presentation. Think that was a good sketchbook of stuff. Yeah.

Eben 1:25: It generated the infamous hacksawing moment. You brought prototypes in and we got the hacksaw out and started sawing — “Wouldn’t it look better if we sawed the corner off it like this?”

Gordon 1:31: It turned out it wouldn’t.

Eben 1:31: We didn’t select that design.

John 1:34: Really happy we got a photo of that. Yeah, there’s, kind of, feedback, and then there’s taking a hacksaw to a prototype. Yes.

Eben 1:40: But I remember coming to see you guys in Bristol. I think I gave a talk in Bristol and then I dropped by the office and saw all the work KD had been doing. And then it was about a year, wasn’t it? So we were about a year in, must have been 2013. And the market was dominated by, well there was Pibow, obviously —

Gordon 2:02: Yes.

Eben 2:02: And then there were —

Gordon 2:03: And then there were some cheapy cases.

Eben 2:04: There were some cheapy cases. And so there was kind of like the beautiful, I remember there was the beautiful but, you know, deluxe-priced case. And then there were a lot of, sort of, discount — 50p cases that looked like 50p cases. And I remember that brief is, can we bring a good design ethos to a relatively low price point?

John 2:25: Yeah, and hit that middle ground between the two. There’s definitely, in the market, groups at either end, and there’s good opportunity kind of right in the middle of: well designed case that is at an accessible price point.

Gordon 2:36: Yeah. And then you drew the Boba Fett corners and then never delivered them to me.

John 2:39: No, sorry about that!

Eben 2:41: Yeah, the original — well, what was then the Raspberry Pi B+ case — because it was at the same time we were developing B+ to the new form factor; we knew we had a new board form factor coming and we wanted to rendezvous with that with a good case design. And yeah, so that had a clip-on lid, didn’t it, and clip-on sides, and originally had a clip-on end. So you had that, kind of, what he calls the Boba Fett thing, the kind of helmet-type —

Gordon 3:06: Yeah, it was the helmet corner wasn’t it. Yep.

Eben 3:09: Yeah. And then the end piece went away.

Gordon 3:12: Yeah. So you ended up just with, you know, half a Boba Fett. Yeah, no, that’s it, yeah.

Eben 3:16: But yeah, so that came out, that must have come out at the start of 2015, because I think that came out round about Big Birthday Bash 3. Do you remember standing in the office clipping them together? We gave one to everyone who came to the Big Birthday Bash —

Gordon 3:33: Oh, yes, most expensive manufacturing line in the world. There’s like, you know, twelve senior software engineers all sat clipping pieces of plastic together. Yeah, that’s it, yeah. A thousand — was it a thousand? I think it was —

Eben 3:45: It was a lot. It was certainly many, many hundreds.

Gordon 3:48: It was just for the birthday bash, course it was, yes, thats why, yeah.

Eben 3:51: Yeah. Yeah. It was kind of fun, right? And then we’ve been working with the same plastics, the same moulding partner all the way through.

John 3:59: That’s right, yeah. So that’s been great. We’ve built a knowledge of what to do with plastics, and that produces a really good cosmetics and functionality. We have our own stock of plastics and our own partners that we’re used to develop through.

Eben 4:16: And that’s T-Zero in Dudley. So we should probably talk about so — so we did a case, we did a case for Raspberry Pi 3; then we did a case for Raspberry Pi 4; probably somewhere in the middle there we’ve got mouse and keyboard? I guess, yeah, we had mouse — and so we did case for Pi 3; mouse and keyboard, of course the keyboard design already being intended to become the Pi 400 design; then a Pi 4 case?

John 4:40: Yeah, and Zero case, and 3A case.

Eben 4:44: Yeah, and I guess Zero and 3A+ case, they sort of refined the design aesthetic a little bit — I mean, those, I think, start to feel much more like modern — much simpler, they lose the clip-on sides.

Gordon 4:55: I think it was the simplicity that actually, that simplicity encouraged the direction of how we do things. Because, if you like, A+ or, actually, Zero as well, the idea is just a two-piece clip and clip together, and it’s like, actually —

Eben 5:08: The red base and the white lid can look as good as a red base with the white sides and a white lid, or better because it’s cleaner. So we had those, and then Pi 4 was the big — I guess Pi 4 was the big one, right?

John 5:18: Yeah. So that was the two-part case for the Raspberry Pi 4. So that was good; I think aesthetically it was it was better. And yeah, I think it’s done quite well.

Eben 5:30: Does that have the polished — that has the polished edge piece on it?

John 5:35: Yeah, so that was the first time, I think, we brought that in, just to add a bit of detail around the lid. So it’s got a gloss detail all the way around the chamfer, which kind of adds to the look of it.

Eben 5:47: Because we have the — the rest of the whole Pi 3 case is is textured, right, has a fairly fine matte texture, right?

John 5:57: Yeah. And I think it was successful, where we have logos and we have the selective texturing — so, matte versus gloss textures — it’s got, you know, just adds that bit of signature detail that’s really nice. And the more places that can exist on the case, the better, I think; it’s quite a nice detail to have.

Eben 6:12: And then you have two parts. And then you have a light pipe component that brings the colour of the board LEDs out through the wall?

John 6:20: Yep. And, yeah, some silicone feet to make it stable on a desktop surface. It was a pretty simple case that.

Eben 6:26: And it was a nice product, but some people felt there was a problem with it, right?

Gordon 6:33: Yeah, Pi 4 got a bit warm inside. Got a little bit warm inside. And that was when, you know, my — what I did was spend quite a long time trying to work out how you could put a fan inside, like hold a fan inside, in such a way as to drive some air through the case —

Eben 6:53: You bought a lot of Chinese takeaways.

Gordon 6:53: Yeah — cut up a lot of stuff and, like, made lots and lots — and it was that interesting thing where I started out by making quite complex things that are sat into the case, and then what I ended up with was like a piece of — like a single piece of card — a little hot, and then, you know, it sat there and it —

Eben 6:54: Diagonal fan.

Gordon 7:14: Yeah. And that just works. And you’re like: Ah, okay, yes, I can get it to that simpler… And that’s a really great thing to do. So you know, as we’ve done with this one, it’s actually realising that it doesn’t need to be complex to get there. But yeah, reducing the temperature inside the case is just like — when you’re trying to do something really hard with a Raspberry Pi, you can consume a lot of energy, and you do need to get rid of it.

Eben 7:43: So this generated the fan shim design, which clips inside the lid; it latches onto the inside of the latches —

Gordon 7:54: Almost like they were designed for it!

Eben 7:57: Almost like they were designed for it — absolutely 110% was not designed for it. And that’s sucking air in, that brings air in over the top of the jacks, particularly the Ethernet jack, pushes it down onto the board, and then kind of exhausts it through the SD card slot and other ad-hoc spaces.

Gordon 8:16: Yeah, and that was quite interesting, because you can tell — you can do things like take the infrared camera, you put the thing on the table and you can take the infrared camera and point it around it, you can see where the table warms up to say, well, where’s the heat going? And that’s actually quite nice; you know, the infrared camera’s brilliant for that kind of stuff, so, yeah. Really useful.

Eben 8:34: So the interesting thing, I think, for me about the thermal behaviour of Raspberry Pi 5 is that it is a lot cooler, at a given workload, compared to — because it’s on a — the processor’s — there are various architectural efficiencies in the system. And in particular, the processor’s on a more advanced process node and is a more efficient core, instruction for instruction, even on the same process node. But because it’s such a powerful core, it has this kind of headroom —

Gordon 9:01: Just goes up even further —

Eben 9:02: You can push it, once you push it and it’s running three times faster — two-and-a-half, three times faster — than a Raspberry Pi 4, it can consume a little more power. So I think we can get — in our worst case, power consumption on a Pi 4 is eight-and-a-half, eight to nine watts. And this is more like 11 to 12 watts, with a pathological workload. Which, when it’s doing kind of three times the work, it’s consuming 50% more power and doing three times the work, right? So…

Gordon 9:36: You know there’s going to be a problem. We have to start — and that was our discussions: by design, we have to — we might as well put this in there by design. Because you know, there isn’t — and again, you know, since that point it’s kind of like: No no no, the case will be supplied with the fan, because if you don’t, you know it’s going to overheat. So it’s like, what’s the point — although saying that, again, in the same situation, as you say, if you’re just in idle, it doesn’t overheat. So you know, it’ll be fine. But it’s just when you hit those worst loads —

Eben 10:06: It’s those intensive use cases… Take a Raspberry Pi 4, I use a Raspberry Pi 4 at home without a fan in the case, and it’s fine because I’m using it as a desktop computer. I’m not just spam building the kernel all the time. So anyway, so the idea was we needed to have something that had some sort of thermal solution in it: what was the evolutionary process that generated the Pi 5 [case]?

John 10:28: Sure, yeah, so, it really, similar to your process in creating the fan inside the Pi 4 case, it’s an iterative prototyping process, really. What fan do we need? Where’s the best place for it to be positioned? What’s the spec of the fan that will produce good cooling performance and low noise? So that was the starting point. And then —

Gordon 10:48: I mean the biggest advantage he [John] had, of course, is that he had a 3D printer, I only had the takeaway cartons. Right. So yeah, I think —

Eben 10:55: Yeah but you got delicious takeaway, right?

Gordon 10:57: That is true!

John 10:57: I remember Gordon handing me the Box of Knowledge.

Gordon 11:01: Yeah! [laughs]

John 11:02: I was like — takeaway bits?

Gordon 11:03: Like, “Here are all the things!” You’re, like, “What is this?”

John 11:05: Had to blow the dust off of it. But there was a lot of inspiration in there! It’s good, it’s good. Yeah, I mean, we did —

Eben 11:11: Some residual special fried rice as well.

John 11:15: It’s great. I’ve still got it somewhere. Yeah, I think we did some thermal simulation work. So we used a computer to understand airflow and replicate what a fan does in software; we did the thermal imaging things. But the best thing was just creating probably hundreds of prototypes — 3D-printed, cardboard — and just testing different positions of fans, and then stress-testing Raspberry Pi, and then measuring the temperature; and we arrived at the 30 millimetre fan directly above the CPU; fix that and then design the rest of the case around that, effectively.

Eben 11:50: And what you’ve ended up with, well, from this distance, that looks exactly like a Raspberry Pi 4 case.

John 11:55: Yes.

Eben 11:55: So how is it different? What’s the concept, what’s the airflow concept in the design?

John 12:01: Yeah, absolutely. So, yeah, it’s taken all the positive points from Pi 4, and then integrated the fan inside. Two main aims: create a cooling solution for the case — keep the Raspberry Pi nice and cool — but also improve its functionality, I guess, for people using it. What we’ve realised with our case is that people use it in many, many different ways: there’s the out-of-the-box, desktop computer mode, but people hack, mount, stack our cases, and we’ve also built in some features that enable it to be a more useful case for more people in different scenarios.

But yeah, I think the process is really fixing the fan in the right place, then understanding how it opens; all of our cases we like to clip together, so we don’t necessarily like to hide the Pi away or make it hard to get to, we want to kind of allow people to interact with the Raspberry Pi inside. So making it all come apart is really useful, so that’s a base requirement. And then, yeah, building in features that just make it more useful, so we’ve got mounting points on the base, so you can mount the case, stack the case, fix the Raspberry Pi in there securely with screws, if you’d like.

But I think a key thing with the fan integration is, when you have a fan case, often the fan dominates the industrial design, so, you know, the cases have got a big hole or lots of venting, and it’s very much a fan case. Whereas we still wanted to keep the minimal nature of this, keep it quite simple, quite friendly looking. And that’s the reason why the fan is actually almost hidden inside. So if I can kind of —

Eben 13:37: Yeah, take that one apart.

John 13:37: Yeah. So, this is its desktop mode, fully assembled, and yeah, this is how people might use it as a desktop computer on the desk. But if you open the lid — so that easily plugs on, clips on and off — and you have the fan integrated right into the centre of the case there. Purely based on thermal design, this is the best place to have the fan. It’s the best size of fan for cooling performance and noise; sits directly above the CPU. With this it’s almost a two mode case; you have this as a discreet, minimal desktop computer, but you can take it off and almost have a project mode. So immediately you’ve got breakout for GPIO, you’ve got extra mounting points revealed as well, places for cables to exit. So with these mounting points on top, it enables the cases to be stackable, so you can build something like this — a tower of cases — if that —

Eben 14:32: You get — those are little spacers you’ve got there.

John 14:34: Spacers, yeah: so by combination of screws, spacers, standoffs, GPIO header extenders, you can create different configurations; basically build the case into whatever projects you’d like using those features. So, yeah, I think stackability was something we heard as being quite desired, and it’s great to build in those features to make the case more usable. The other good part about having these mounting features here is integration of HATs. So often with a HAT, you’re almost occupying the space where a fan would be good to go. So what we’ve done is allowed HATs to be mounted on top of the fan, so that produces something like this — that’s just a mock-up there — so, again, using spacers, GPIO header extenders, you can have cooling inside, but all manner of HAT mounting on top as well.

The other feature of that is, the fan is on a removable component: so this clear component could be taken out. So you don’t necessarily have to use the fan if you don’t want to. So for example, with the Pi 4, using it as a home desktop computer, you might not need a fan in that place, you could take that out entirely. What’s quite nice about that is we’ve got this nice picture-frame-style feature. And you can have the HATs inside the case as well. And some of the more visual HATs with banks of LEDs, really nice to frame in that aperture and have a visual impact of the HAT.

Eben 16:00: So if I clip the lid on, where’s the air going in?

John 16:04: So we have about 1.5 millimetre gap all the way through.

Eben 16:09: OK, yeah.

Gordon 16:10: I never — I honestly — like, we spent a great deal of time and I was kind of like —

Eben 16:13: I’m kind of amazed, I’m —

Gordon 16:15: When I did it, I — I’m surprised. And when you showed it and you’re like yeah, it works, I’m like: How did it not work for me then?! When I was like, you know, with all these little — I used to, I thought you just wouldn’t be able to get the airflow through. But I guess, because it’s all the way around, then that’s what really helps in this situation.

John 16:31: Yeah. Absolutely. So although it’s quite a small gap, and it’s discreet — we didn’t want the fan to dominate the design — the surface area of that gap equals the through-hole surface area of the fan. So that’s a kind of direct comparison. Yeah, there was a lot of raising and lowering the fan, the — the lid, to get it correct. But, yeah, it’s a nice feature line; again, we’ve got vents on the base, but I think —

Eben 16:57: And that’s a change from the — The Pi 4 case with the fan shim is really relying on, effectively, air leakage under the PCB, primarily through the SD card slot, we think, to get air out; this actually has features for that.

John 17:12: Yeah, it’s dedicated features, so, deliberate air inlet through the gap, and then deliberate air exhausts through base vents, and we found with the thermal imaging that a lot comes out of the ends connected here. So we know where the air exits and enters the case. The thermal simulation work we did helps us understand the path of the air through the case, so that was really useful. But yeah, iterative prototyping approach to get the gap right, to get the position of the fan right, and make sure there’s enough venting as well.

Eben 17:45: Who did the simulation? Was it Cambridge Consultants?

John 17:47: It was, yeah, yeah.

Gordon 17:49: Although — they did — sorry — they did the simulation for the bulkhead design for the — Yeah. That thing. But actually, you did the one for this one, so —

John 18:01: Yeah — I hadn’t had much experience in that, but kind of learnt how to do it. So yeah, as part of the — a bolt-on to the CAD software, you could set up certain parameters with the 3D model in CAD, and it gave you a visual interpretation of what the hot air and cold air was doing, which was quite useful. So the position and size of the vents were driven by that simulation.

Eben 18:23: And you’ve also stretched the case a little bit in, in width, whichever dimension you want that to be. It’s stretched away near the SD card, which I guess helps with airflow?

John 18:33: Exactly, yeah.

Eben 18:34: And also makes it — there’s a bit of a wrinkle, isn’t there, with the previous case?

Gordon 18:39: Yeah. Well, the one problem is that I’ve always — people have wanted to have — can you have a push-push connector, like we have on the Pi 400? But I have no fingernails! So it’s always annoying when we have that. I’ve always said, you know, can we make sure that it’s easy to insert and reset? Which requires actually quite a large gap, doesn’t it? And then it’s quite difficult, then, to make it large enough and still look nice. I mean, that spent — spent a long time with that.

John 19:08: We did, yeah. I think the size of that finger recess has been highly developed, you know, and different people’s fingers and things. But yeah, I think that’s quite a generous feature for people. it makes it a lot easier to —

Gordon 19:23: And there was also the problem, I think, with the Pi 4 case: sometimes you could, because of the way the board sat in the case, sometimes you could put the case — put the SD card [in] and actually go under the board. And then you’d have to, you know, shake it back out again and, you know, find the slot. Whereas you don’t have that issue with this one.

John 19:40: Yeah. Yep.

Eben 19:41: And I guess this is kind of an extension, to the case space, of that ethos that we have in the board designs, where because we always try and be incremental from generation to generation, we can fix problems. We’re not just — if we did a completely different board design every generation or a completely different case design every generation, we’d make a completely new set of mistakes every generation. Whereas this time, we can iterate and have some confidence each case is going to be better than the previous one.

John 20:04: So yeah, I think we’ve learnt a lot from the ones we’ve done before and this is the culmination of that knowledge, I think —

Gordon 20:10: Yeah. But yeah, that point at — there were two things that — so we have this extra bit over here, right; now that fixes two things: one is — means that the board won’t lift up, as you push the SD card in, won’t lift in. But also, we definitely saw some people taking Raspberry Pis and just pushing it like — and then forgetting their SD card’s there, and actually pushing it in and actually then damaging an SD card. So that also stops that; if you try and do it, it’s obvious it won’t fit. And there’s — we were discussing, how the user interacts with the case is really important. How does it — because again with Pi 4, there was almost this magic, direct way you had to insert it [a Pi] —

Eben 20:59: Yeah there was a sort of —

Gordon 21:00: Yeah — connectors in first, and then, and that kind of thing. And then, with this one, we tried to get rid of as much of that — so it would just go in, at any direction, but it would then have all those things, right. And — you spent a long time on all of those, right?

John 21:17: It’s always a good design challenge, because we have connectors around different sides of the board. So loading it in in that end, which is the most intuitive way of doing it, is challenging to get distances to connectors. But I think we’ve arrived at a good point where the Pi almost just drops into place. It is intuitive, it’s obvious, you don’t have to learn a particular method for loading it.

Gordon 21:38: Yeah, but you can still take it out with the SD card, and you can still put it in, but you just can’t do that. It’s obvious that it won’t work, so…

John 21:48: That’s it.

Eben 21:49: And then the light pipe is a little bit more sophisticated, because we, well we grew a much desired feature on the board, didn’t we?

John 21:55: Yes, it’s an on-off button. So yeah, you can click it, hold it down to power on Raspberry Pi, and then hold it down to power down. And it also acts as a light pipe, so you get the status LED lighting up that button, so you’ll have that external appearance of what the LED’s doing.

Gordon 22:14: There was a whole new [injection moulding] tool for that one as well wasn’t there?

John 22:15: There was, yeah. Yeah. Yeah, that was a challenge. I mean, it’s fairly similar to the Pi 4 light pipe, but we obviously wanted it to move, and the other one we didn’t want to move, so it has a kind of pivoting action. So you can press the button and activate the switch on the Pi 5.

Gordon 22:31: But you also had a lot — some more software for that one. To do the light pipe.

John 22:34: Yeah, yeah, I did. Yeah, yeah. So that was ray tracing software, so, we — same kind of 3D software, we could light up the LED and then shoot the rays through, and then just understand whether we were directing the light in the right way through.

Eben 22:37: Cause yeah, light pipe design has felt like a bit of a dark art, right, a bit hit-and-miss in the past.

Gordon 22:56: And you’re just like, you know, there’s that thing about making sure it wasn’t just a — you didn’t end up with some dots that you couldn’t actually see at any kind of angle, and you could only see if you look in the end; trying to get rid of that. So trying to make it bounce around a bit was a good idea.

John 23:12: That’s right, yeah. The more lines the better. Yes. Ray tracing.

Gordon 23:17: But hopefully, we’ve learnt a lot that we can then use in the future as well.

John 23:20: Absolutely, yeah.

Eben 23:21: But it’s been a good development, and I think it’s been a nice evolution of the design language. It’s just an incremental evolution of the design language, so I imagine future products will, you know, some of the stuff we’ve learned here is really going to help us with future products.

That’s case; we should talk about — but that’s only one of two cooling solutions for the product. Shall we talk about the other one?

John 23:46: Yeah. So, this is the Pi 5 Active Cooler product. This is essentially an active heatsink. It’s a product that mounts directly to the Pi 5, which is purely focused on cooling. It’s made up of aluminium baseplate heatsink, and mounted directly to that is a blower fan. So this fan blows air out sideways through these heatsink fins, and does a really first-class job of cooling the Raspberry Pi 5. It’s been a great one to work on. The initial aims were to make it small and compact. Really, we knew it’s going to live on the Pi 5 for quite a long amount of time, so the more it can blend in and occupy the space we have and almost become a part of the Pi 5, the better. We occupy all of this space in between the pretty feature-packed Pi 5, so the shape almost designed itself, but although it’s a functional product, we wanted it to look good as well. I think we’ve got to a good result. The way it mounts is by two push pins; so, the Pi 5 has two dedicated holes for heatsink mounting —

Eben 25:00: It’s kind of remarkable that along with everything else, James also managed to eke out another two mounting holes’ worth of space on the board. There’s really not a lot of space.

John 25:08: That’s great.

Gordon 25:08: Yeah, and especially in this corner is not the best corner to have a hole.

Eben 25:12: It’s a bit full of inductors.

John 25:13: Yeah. So yeah, it does a really effective job. So it’s made up of aluminium baseplate heatsink; the blower fan screws directly to that, so it’s got some pretty robust threaded inserts. It screws together really strongly to push pins either side. And on the underside, we have strategically positioned thermal gap pads. So these contact the components that get hot, so, PMU, SoC, components on the board. And they’re at different heights, so it helps stabilise the heatsink when it’s mounted on and has good thermal conductivity. The fan is similar to the Pi case: so it’s a four-wire fan, it’s power, ground, and PWM. It’s a temperature-controlled fan as well, so it will tailor its speed depending on how hot the CPU gets. So it’ll go through the different gears. And it’s a really silent fan, I think that was really important when we specified it, the noise only really kicks in at the top speeds. So that was really important for us to look at. It’s also got a tachomotor wire as well, so you can look at the RPM of the fan through the software as well, which is really useful. But yeah, it should be — well, it will be — assembled fully out of the box, it will come like this. The user will just take away the backing paper from the thermal gap pads, then it just mounts pretty easily by pushing onto the board, and connect the wire and ready to go.

Eben 26:46: How’s the aluminium component made?

John 26:50: Sure. So — it’s — there’s a kind of shape we wanted to produce. We knew it wanted to have heatsink fins. The first operation in manufacture is an aluminium extrusion. So essentially the side profile is put through a die; it comes out as a big long bar with all the heatsink fins in the side profile all the way through. Then it’s CNC machined, and it’s got a stamping process as well to create the profile. So the edge is a secondary operation. And then we have the threaded inserts pressed in. So there’s a few different operations but we —

Eben 27:22: So it’s CNC to make the — so it’s extrusion to make the slots that way, the heatsink slots that way, CNC to make them that way, and then stamping to generate the outline.

John 27:34: Exactly, yeah. The main fin profiles are through the extrusion, then it’s cross-cut with CNC; the profile is stamped as well, and then the CNC kind of cleans up the edge, essentially.

Eben 27:44: Your blower is blowing into this forest of fins; it’s pulling air in like that, and then blowing it tangentially outwards into the forest.

John 27:52: Exactly, yeah. And with the manufacturer’s help, we put a waveform into the fins as well. So it’s got that little bit of extra surface area just to help with heat dissipation.

Eben 28:01: I notice the fins, they’re not just rectangles, they’re little Christmas tree shapes.

John 28:05: So just that slight bit of detail adds a little bit more performance.

Eben 28:09: What’s that worth? Couple of degrees?

John 28:11: Yeah, I’m not quite sure, it’s hard to … but yeah, it was recommended to do, so it must make a substantial difference, yeah. But yeah, it’s hopefully quite a simple product, and will come fully assembled, and can just plug on.

Gordon 28:29: Yeah, and I mean, I think there’s that thing about it being — because one of the things I’ve always had the problem with, with the case, is that, well — home is fine. So, like, it’s sat on the — because I don’t really do much, you know, it’s just sat there which isn’t — it’s one of the computers I’ve got sat there, it’s just the Raspberry Pi, it just sits there. But at work, because I’m always plugging things and unplugging things, I put it into the case, and then about a few days later, I’ll have to remove the case to unplug something and plug something else in, and then… So this does allow you to just leave it plugged, leave it like that, leave that as a cooling solution rather than inside the case. And I think there is definitely — both of those options are valid uses of the Raspberry Pi. So, you know, just sat on the desk as a raw board is really good as well.

John 29:13: Yeah, I think keeping it small and compact was just an absolute requirement, because as you say, it just gives you still the freedom to do what you’d like with the Raspberry Pi, with the insurance of this cooling solution on board.

Gordon 29:25: So the, um, how good is, in comparison, the cooling?

John 29:29: Yeah, so, this is higher-performance, because it’s obviously in open air, and it’s dedicated, it’s got metal componentry as a heatsink. So, this is better performance; there’s probably about a ten-degree difference between the two. Obviously, a lot of variables in thermal testing, but on a like-for-like test, this is probably ten degrees cooling better.

Eben 29:52: And this is — these fans are rated for quite a lot of use. Right? They’re not intended to fail after a year.

John 30:01: That’s right, yeah. It’s years and years. I think 50,000 hours, so a good amount of use.

Eben 30:05: And that’s 50,000 hours of use. So it’s 50,000 hours, you know, if your Raspberry Pi is idle, the fan’s not running. So this really is 50,000 hours, this is intended to be 50,000 hours of pretty intensive use of your Raspberry Pi.

John 30:17: That’s right. And obviously the lower temperature trip points, it won’t be going full speed, so that will extend the life. And we did pick particular fan technology; so the bearing type is built for longevity, and low noise. So the spec of the fan was very important in extending its life and being really quiet.

Gordon 30:37: Yeah that’s kind of something we learnt from the other one, it was a bit whiny. So it’s good to have a much quieter solution.

John 30:46: It’s quite challenging; it’s not just the fan spec, because often you can have a fan running in mid-air and it’s super silent, but when it’s in contact with something, especially plastics, it’s, you know, reverberation and… Quite a lot of work was done [on] how we mount the fan on the case just to reduce vibration and still have a low-noise solution.

Eben 31:06: It’s fun. And both of these are available at launch. In significant quantities — significant quantities of these will be available when the product launches. It’s cool! So everyone gets a — maybe not quite everybody gets a case, but everybody gets a thermal solution nice and early on, in parallel with having a design that, as we say, has been designed to be cooler at a given workload than its predecessor. Exciting! You keep doing more industrial design.