Kritik sah

Water timers are nifty devices that can water the lawn at set times or keep that vegetable garden from turning into a dustbowl. When [electronupdate] timer refused to output water on any of its three outlets, he did the right thing. Instead of angrily checking the warranty on the sodding thing, he tore it apart to attempt a repair . As expected, the design of these devices is quite straightforward. Three solenoids control whether an outlet is open or closed. A control board also handles the user controls and display. There was no obvious sign of damage, and the PCB was potted in a white substance that should have kept out any moisture. A quick check with a battery revealed that the three solenoids also worked just fine, so the cause likely was somewhere on the — potted — PCB. These solenoids are rated for 6VDC and take about 20 ms to act, but on an oscilloscope capture it was plain to see that the board was only putting out around 2V. This wasn’t enough to drive the...

The RP2350 is actually a pretty secure chip, all things considered. It has secure boot, ARMv8’s TrustZone to split secure and non-secure execution, and you can permanently disable debug — the Pi Foundation even included glitch detection, meaning the traditional ‘zap the chip until it obeys’ technique is blocked. That’s why the [Ledger Donjon] security team went full Bond Villain and strapped everyone’s favourite fruit-flavoured microcontroller to a table with a slowly-approaching laser beam. The bench setup to do all this is pretty impressive– and came with an impressive 250,000 USD price tag. Okay — movie clichés aside, the laser was in fact very carefully focused on target before they turned it on. That target was the register that enables the 2350’s debug features. Said register was located by decapsulating the chip and examining the die with photon-emission electron microscopy; the actual attack was carried out on a chip that had be...

A Linux handheld computer is, in theory, easy and inexpensive given the availability of single-board computers, but in practice the budget invariably edges well into three figures. There’s an interesting alternative from [bkovac] that won’t break the bank as much, using a cheap 4G wireless hotspot, an iPhone USB keyboard case accessory, and, though a cheaper display could suffice, a fancy Adafruit Sharp memory display. The hotspot is available from AliExpress for around 20 dollars/Euros/pounds, and it’s referred to by its model number, MF800. It’s powered by a Qualcomm MSM8916, also known as the Snapdragon 410, which you might have found in a budget cellphone early in the last decade. Importantly, though, it’s supported by mainstream Linux, and while it’s by no means the fastest on the block, it can be a poor man’s alternative to a Raspberry Pi. It comes with a small SPI display, but this project replaces it with a much bigger Sharp SPI memory...

This article is written on an open-source operating system, but not an open-source machine — the BIOS isn’t open-source, and even if it were supported by the coreboot project (formerly LinuxBIOS), there would still be a whole host of binary blobs required to get it to boot. On one vintage architecture, there’s one less blob, as coreboot can now initialize DRAM on Intel Bay Trail SOCs, as [Mate Kukri] presented in a talk at the recent Open Source Firmware Conference. Bay Trail isn’t exactly cutting-edge hardware, to be sure — the SoCs are over a decade old at this point, and were only used in low-performance mobile applications like Chromebooks. On the other hand, coreboot has been on Chromebooks for at least as long. Getting DRAM set up is difficult because, well, you don’t have any memory to work with until you do. Traditionally, the way you did that was to call on one of the many proprietary ‘binary blobs’ provided with next to no docum...

If you’ve used MicroPython much, you know that debugging usually amounts to printing a few things out, trying your code out, and then repeating. But [ghi-electronics] wants you to have full on-chip source-code debugging in Visual Studio . You don’t need anything special to use it — just a supported MicroPython host and the same USB cable you program with now. The downside is that you either have to build a custom MicroPython image and flash it or use one that they include. They support several Raspberry Pi Pico versions and ESP32 chips, as well. However, at least one “odd” Pico we had lying around wouldn’t take the firmware. A stock one did, and it worked as you would expect. A little more investigation showed the odd Pico (an RP2040 GEEK) probably did take the firmware; it just produced an error during setup. There is a known problem with Linux and the ESP32-S3 having similar behavior. Of course, you can build your own image, but now you are talki...

In 1982, desktop computers were coming into their own, and no clear leaders had emerged. But everyone knew they wanted a piece of the action. This led to, among other things, Sony’s SMC-70 , which, frankly, for 1982, was a good-looking, if not oddball, machine. [Tech Tangents] shows the machine off in a recent video. From the front, the computer looks more-or-less like everything else. But as you move backward, you can see this computer wasn’t another typical entry into the market. One of the things that was the hallmark of successful business computers of the day was expandability. The earlier Altair had the later-titled S100 bus. The IBM PC had the ISA bus. But in both cases, you had to open the box to plug and unplug cards. The SMC-70, though, had a very unique system. Instead of boards, users would line up modules and stab them with what amounted to skewers to mechanically secure the stack of modules. You could stack some modules vertically or horizontally using ribbo...