New 2 GB Raspberry Pi 5 Has Smaller Die And 30% Lower Idle Power Usage

August 30, 2024 by Maya Posch 16 Comments

Recently Raspberry Pi released the 2GB version of the Raspberry Pi 5 with a new BCM2712 SoC featuring the D0 stepping. As expected, [Jeff Geerling] got his mitts on one of these boards and ran it through its paces, with positive results. Well, mostly positive results — as the Geekbench test took offence to the mere 2 GB of RAM on the board and consistently ran out of memory by the multi-core Photo Filter test, as feared when we originally reported on this new SBC. Although using swap is an option, this would not have made for a very realistic SoC benchmark, ergo [Jeff] resorted to using sysbench instead.

Naturally some overclocking was also performed, to truly push the SoC to its limits. This boosted the clock speed from 2.4 GHz all the way up to 3.5 GHz with the sysbench score increasing from 4155 to 6068. At 3.6 GHz the system wouldn’t boot any more, but [Jeff] figured that delidding the SoC could enable even faster speeds. This procedure also enabled taking a look at the bare D0 stepping die, revealing it to be 32.5% smaller than the previous C1 stepping on presumably the same 16 nm process.

Although 3.5 GHz turns out to be a hard limit for now, the power usage was interesting with idle power being 0.9 watts lower (at 2.4 W) for the D0 stepping and the power and temperatures under load also looked better than the C1 stepping. Even when taking the power savings of half the RAM versus the 4 GB version into account, the D0 stepping seems significantly more optimized. The main question now is when we can expect to see it appear on the 4 and 8 GB versions of the SBC, though the answer there is likely ‘when current C1 stocks run out’.

3D Printering: Klipper, The Free 3D Printer Upgrade

August 29, 2024 by Al Williams 33 Comments

I have several 3D printers, and I’ve always been satisfied with using either Repetier or Marlin on all of them. There are a few other firmware versions that could run on my hardware, but those two have been all I’ve needed. Sure, it was painful for a while having to juggle features to fit the firmware image onto the smaller microcontroller boards. Now that Marlin supports big 32-bit boards however, that hasn’t been a problem. But recently, I’ve been on a program to switch everything to Klipper.

In this post, I’ll tell you why I did it and give you some data about why you might consider it, too.

The Landscape

Marlin is written in C and burned into a 3D printer’s flash memory. It does a lot. It receives G-code commands, interprets them, and translates them to meaningful actions on the hardware. Modern versions handle automatic transformations to account for lumpy beds, input shaping to reduce shaking, and linear advance to produce better prints.

It might seem simple to control a 3D printer, but there are lots of little details to take into account. For example, if you are moving the head between two XY coordinates and you expect a certain flow rate, then you have to figure out how fast to turn the steppers to get the right amount of plastic out over that time. You also may have to retract before you start a move, make sure temperatures are stable, and transform the actual coordinates based on bed leveling data. There’s a lot going on.

Klipper does the exact same job, but it does it differently. On the 3D printer board is a tiny piece of software that does very little. It’s a bit like a device driver for the printer. All by itself, it does nothing. But it can handle very basic commands that describe how to move the machine.

All the rest of the processing you expect to happen now runs on some Linux computer. That is very often a Raspberry Pi, but it could be a spare laptop, your desktop computer, or anything that will run a reasonable Linux install. Several vendors even sell single-board computers with touchscreens made specifically for running this part of Klipper.

However, even though a screen is nice, you don’t really need it. I’ll talk about that more later.

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Hardware Bug In Raspberry Pi’s RP2350 Causes Faulty Pull-Down Behavior

August 28, 2024 by Maya Posch 50 Comments

Erratum RP2350-E9 in the RP2350 datasheet, detailing the issue.

The newly released RP2350 microcontroller has a confirmed new bug in the current A2 stepping, affecting GPIO pull-down behavior. Listed in the Raspberry Pi RP2350 datasheet (page 1340) as erratum RP2350-E9, it involves a situation where a GPIO pin is configured as a pull-down with input buffer enabled. After this pin is then driven to Vdd (e.g. 3.3V) and then disconnected, it will stay at around 2.1 – 2.2 V for a Vdd of 3.3V. This issue was discovered by [Ian Lesnet] of [Dangerous Prototypes] while working on an early hardware design using this MCU.

The suggested workaround by Raspberry Pi is to enable the input buffer before a read, and disable it again immediately afterwards. Naturally, this is far from ideal workaround, and the solution that [Ian] picked was to add external pull-down resistors. Although this negates the benefits of internal pull-down resistors, it does fix the issue, albeit with a slightly increased board size and BOM part count.

As for the cause of the issue, Raspberry Pi engineer [Luke Wren] puts the blame on an external IP block vendor. With hindsight perhaps running some GPIO validation tests involving pull-up and pull-down configurations with and without input buffer set could have been useful, but we’re guessing they may be performed on future Pi chips. Maybe treating the RP2350 A0 stepping as an ‘engineering sample’ is a good idea for the time being, with A3 (or B0) being the one you may want to use in actual production.

In some ways this feels like déjà vu, as the Raspberry Pi 4 and previous SBCs had their own share of issues that perhaps might have been caught before production.

(Note: original text listed A0 as current stepping, which is incorrect. Text has been updated correspondingly)

What’s New In 3D Scanning? All-In-One Scanning Is Nice

August 27, 2024 by Donald Papp 29 Comments

3D scanning is important because the ability to digitize awkward or troublesome shapes from the real world can really hit the spot. One can reconstruct objects by drawing them up in CAD, but when there isn’t a right angle or a flat plane in sight, calipers and an eyeball just doesn’t cut it.

Scanning an object can create a digital copy, aid in reverse engineering, or help ensure a custom fit to something. The catch is making sure that scanning fits one’s needs, and isn’t more work than it’s worth.

I’ve previously written about what to expect from 3D scanning and how to work with it. Some things have changed and others have not, but 3D scanning’s possibilities remain only as good as the quality and ease of the scans themselves. Let’s see what’s new in this area.

All-in-One Handheld Scanning

MIRACO all-in-one 3D scanner by Revopoint uses a quad-camera IR structured light sensor to create 1:1 scale scans.

3D scanner manufacturer Revopoint offered to provide me with a test unit of a relatively new scanner, which I accepted since it offered a good way to see what has changed in this area.

The MIRACO is a self-contained handheld 3D scanner that, unlike most other hobby and prosumer options, has no need to be tethered to a computer. The computer is essentially embedded with the scanner as a single unit with a touchscreen. Scans can be previewed and processed right on the device.

Being completely un-tethered is useful in more ways than one. Most tethered scanners require bringing the object to the scanner, but a completely self-contained unit like the MIRACO makes it easier to bring the scanner to the subject. Scanning becomes more convenient and flexible, and because it processes scans on-board, one can review and adjust or re-scan right on the spot. This is more than just convenience. Taking good 3D scans is a skill, and rapid feedback makes practice and experimentation more accessible.

Continue reading “What’s New In 3D Scanning? All-In-One Scanning Is Nice” →

Fast 3D Printing With A Polar, Four Quadrant Custom Machine

August 26, 2024 by Dave Rowntree 14 Comments

3D printing is all well and good for making low numbers of units, so long as they’re small enough to print in a reasonable time, but what if you want to go really big? Does a 35-hour print time sound like a fun time? Would it even make it that long? [Nathan] from Nathan Build Robots didn’t fancy the wait, so they embarked on a project to build a huge parallel 3D printer with four independent print heads. Well, kind of. Continue reading “Fast 3D Printing With A Polar, Four Quadrant Custom Machine” →

3D Printed Electronics Breadboard

August 25, 2024 by Maya Posch 9 Comments

The printed breadboard cover, seen from the bottom. (Credit: CHEP, YouTube) — The printed breadboard cover as seen from the bottom. (Credit: CHEP, YouTube)

Does it make sense to make your own breadboards rather than purchasing off the shelf ones? As [Chuck Hellebuyck] notes in a recent video on DIY, 3D-printed breadboards, there’s a certain charm to making a breadboard exactly the size you need, which is hard to argue with. The inspiration came after seeing the metal breadboard spring clips on sale by [Kevin Santo Cappuccio], who also has a 3D printable breadboard shell project that they fit into. This means that you can take the CAD model (STEP file) and modify it to fit your specifications before printing it, which is what [Chuck] attempts in the video.

The models were exported from TinkerCAD to Bambu Lab Studio for printing on a Bambu Lab A1 Mini FDM printer. After a failed first print (which the A1 Mini, to its credit, did detect), a model was printed on a Creality K1 Max instead. Ultimately [Chuck] traced this back to the Bambu Lab Studio slicer failing to add the inner grid to the first layer, which the Creality slicer did add, caused by the ‘wall generator’ setting in the Bambu Lab slicer being set to ‘Classic’ rather than ‘Arachne,’ which can vary line width.

After this, the models printed fine and easily fit onto the spring clips that [Chuck] had soldered down on some prototyping board. A nice feature of these spring clips is that they have a bit of space underneath them where an SMD LED can fit, enabling functional (or just fancy) lighting effects when using a custom PCB underneath the contraption. As for whether it’s worth it depends on your needs. As [Chuck] demonstrates, it can be pretty convenient for a small breadboard on an add-on card (with or without custom lighting) like this, but it’s unlikely to replace generic breadboards for quick prototyping. We can, however, imagine a custom breadboard with mounting points for things like binding posts, switches, or potentiometers.

If we had that kind of custom breadboard, we wouldn’t need these. People were making custom breadboards back in 1974, but they didn’t look like these.

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Simulating Air Flow For 3D Printing

August 25, 2024 by Al Williams 1 Comment

You’ve probably heard that a 3D printer is capable of producing its own replacement parts. Sometimes, that even includes upgraded or improved versions of the parts it was originally built with. But sometimes, it’s hard to figure out what improved really means. Think about air ducts that cool the part after printing. In theory, it should be easy to design a new duct. But how does it perform? Empirical testing can be difficult, but [Mike] shows how you can simulate the airflow so you can test design changes and validate assumptions before you print the actual part.

Of course, this wouldn’t only apply to printer ducts. You might also get some tips if you want to model airflow for PC cooling, hot air soldering, or other air-related projects. The free version of the software has some limitations, but it was surprisingly capable.

We also enjoyed how [Mike] used fluid to visualize the actual patterns and compared it to the simulation. The trick is using a compound from a kid’s science project kit, and it seems to work very well. Of course, you could just grab your smartphone. This might be worth thinking about if you are building a laser cutter air assist, too.

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