Author: Jenny List

3367 Articles

Fridge Compressor Teardown Reveals Engineering Compromises

August 20, 2022 by 108 Comments

Probably one of the most reliable devices you will have in your house is the refrigerator, as its compressor has the minimum of moving parts and carries its own lubrication. It’s not uncommon to find fridges many decades old still in use, and fridges are far more likely to be discarded due to broken fittings rather than a failed compressor. An interesting teardown of a failed fridge compressor comes from [turbokinetic], who gives us a professional analysis of how shortcomings in its construction caused it to fail. It’s both an opportunity for a look at the inside of a fridge compressor, and a commentary on the quality of consumer grade hardware.

Electrically the unit seemed unhurt, but the motor wouldn’t pump anything. Cutting the lid off revealed the motor, and it was soon established that the bearing had failed. As the teardown proceeded the conclusion was that the fault lay in the oil being too low viscosity. The designer had picked a very light oil in pursuit of low friction for lower energy consumption, but had ended up with one too light to provide adequate coverage within the bearing. The compressor has a lifetime of around ten years baked into it from manufacture, whether the designer intended it to or not.

You can see the full video below the break, but meanwhile this isn’t the first fridge compressor we’ve seen.

Continue reading “Fridge Compressor Teardown Reveals Engineering Compromises” →

Put 3D Metal Printing Services To The Test, By Making A Watch

August 18, 2022 by 17 Comments

Have you ever been tempted by those metal 3D printing services? [Carter Hurd] has, and puts them to the test with a wristwatch. (Video, embedded below.)

It’s fair to say that among Hackaday readers you will find a very high percentage of 3D printer ownership compared to the general population, but for most of us that means an FDM or perhaps even an SLA printer. These two technologies have both effectively delivered polymer printing at the affordable end of the market, but as readers will also be aware they are only the tip of the 3D printing iceberg. We know the awesomeness of your industrial 3D printer is defined by the size of your wallet, and while our wallets are small, we are offered a chance at the big time through the services of rapid prototyping companies that will print our models on these high-end machines. Thus [Carter]’s project video is as much about using these services as it is about making a wristwatch.

Continue reading “Put 3D Metal Printing Services To The Test, By Making A Watch” →

An EMMC Gives Up Its Secrets

August 17, 2022 by 32 Comments

An increasing phenomenon over the years since mobile phones morphed from simply telephones into general purpose pocket computers has been that of the dead device taking with it some treasured digital resource. In most cases this means the device has died, but doesn’t necessarily mean that that the data has completely gone. Inside the device will be an eMMC flash chip, and if that can be read then the data is safe. This applies to some single board computers too, and thus [Jeffmakes]’ adventures in recovering an eMMC from a dead Raspberry Pi CM4 are particularly interesting.

The whole thing relies on the eMMC presenting the same interface as an SD card, so while it comes in a multi-pin BGA package it can be addressed with surprisingly few wires. Using the PCB from another dead CM4 he traced the relevant connections from eMMC to SoC pads, and was thus able with some very fine soldering to construct an interface for an SD card reader. The disk could then be imaged in its entirety.

This work will be of huge use to experimenters who’ve fried their Compute Modules, but of course the information it contains will also be of use to retrieve those photos from the phone that fell in the bath. It’s not the first time we’ve taken a look at someone’s efforts in this area.

Did You See A John Deere Tractor Cracked At DEF CON?

August 17, 2022 by 6 Comments

The Internet, or at least our corner of it,  has been abuzz over the last few days with the news of a DEF CON talk by [Sick.Codes] in which he demonstrated the jailbreaking of the console computer from a John Deere tractor. Sadly we are left to wait the lengthy time until the talk is made public, and for now the most substantive information we have comes from a couple of Tweets. The first comes from [Sick.Codes] himself and shows a game of DOOM with a suitably agricultural theme, while the second is by [Kyle Wiens] and reveals the tractor underpinnings relying on outdated and un-patched operating systems.

You might ask why this is important and more than just another “Will it run DOOM” moment. The answer will probably be clear to long-term readers, and is that Deere have become the poster child for improper use of DRM to lock owners into their servicing and deny farmers the right to repair. Thus any breaches in their armor are of great interest, because they have the potential to free farmers world-wide from this unjust situation. As we’ve reported before the efforts to circumvent this have relied on cracked versions of the programming software, so this potential jailbreak of the tractor itself could represent a new avenue.

As far as we’re aware, this has so far taken place on the console modules in the lab and not in the field on a real tractor. So we’re unsure as to whether the door has been opened into the tractor’s brain, or merely into its interface. But the knowledge of which outdated software can be found on the devices will we hope lead further to what known vulnerabilities may be present, and in turn to greater insights into the machinery.

Were you in the audience at DEF CON for this talk? We’d be curious to know more. Meanwhile the Tweet is embedded below the break, for a little bit of agricultural DOOM action.

Continue reading “Did You See A John Deere Tractor Cracked At DEF CON?” →

USB-C Charging Mod Brings In The Juice

August 16, 2022 by 13 Comments

By now we’re well under way with the consolidation of low-voltage power supplies under the USB-C standard, and the small reversible connector has become the de facto way to squirt some volts into our projects. But for all this standardization there are still a few places where the harmony of a unified connector breaks down, and things don’t work quite the way they are supposed to. One such case has occupied [James Ide] — devices which will accept power from a USB-A to USB-C cable, but not from a USB-C to USB-C one. His solution? A small flexible PCB upgrade.

The problem lies with how different power supplies and peripherals identify each other, and quite likely in device manufacturers skimping on a few components here and there. A compliant USB-C power supply expects to see pull-down resistors on the data lines, and will thus refuse to serve power to devices that don’t possess them. Meanwhile the USB-A supply will quite happily serve juice without such checks, which is what the manufacturer is relying on. The solution is a tiny flexible PCB with the resistors, designed to be retrofitted behind a USB-C socket. On one hand it’s probably one of the simplest circuits we’ve ever shown you, and on the other it’s a cleverly designed solution to the issue at hand.

If the nitty-gritty of USB-C interests you, then we’ve taken a much closer look in the past.

Thanks to [Andrea] for the tip.

Why Do Brits Drink Warm Beer?

August 16, 2022 by 152 Comments

Traveling through mainland Europe on a British passport leads you to several predictable conversations. There’s Marmite of course, then all the fun of the Brexit fair, and finally on a more serious note, beer. You see, I didn’t know this, but after decades of quaffing fine ales, I’m told we do it wrong because we drink our beer warm. “Warm?”, I say, thinking of a cooling glass of my local Old Hooky which is anything but warm when served in an Oxfordshire village pub, to receive the reply that they drink their beers cold. A bit of international deciphering later it emerges that “warm” is what I’d refer to as “cold”, or in fact “room temperature”, while “cold” in their parlance means “refrigerated”, or as I’d say it: “Too cold to taste anything”. Mild humour aside there’s clearly something afoot, so it’s time to get to the bottom of all this. Continue reading “Why Do Brits Drink Warm Beer?” →

A Simple Streaming Radio Receiver

August 14, 2022 by 12 Comments

For those interested in a career in broadcast radio there aren’t many routes into the business. Student radio, pirate radio, and hospital radio usually feature somewhere near the start of any DJ’s resumé. Hospital radio stations often don’t have a transmission license and have historically relied on wired systems, but since those can’t reach everywhere they are now more likely to look to the Internet. [AllanGallop] has created the Mini Web Radio for the hospital station in the British city of Milton Keynes, a compact battery-powered single station streaming radio receiver that can pick up those tunes anywhere with a wireless network connection.

Inside the neatly designed 3D printed box the hardware is quite straightforward, a WeMos ESP32 board and a MAX98357A I2S digital amplifier module all powered by an 18650 cell. There’s a volume control and headphone socket, which is all that’s needed for the user interface. The software has code for both Arduino and Platform.io and is configured as you might expect through a web interface. Everything can be found in a handy GitHub repository should you wish to build one yourself. Meanwhile, it’s particularly pleasing as a Hackaday scribe to feature a project with roots in one’s own hackerspace, in this case, Milton Keynes Makerspace.

Thanks [Cid] for the tip!