Espressif’s ESP32-P4 Application Processor: Details Begin To Emerge

April 2, 2024 by 54 Comments

Every now and then there’s a part that comes along which is hotly anticipated, but which understandably its manufacturer remains tight-lipped about in order to preserve maximum impact surrounding its launch. Right now that’s Espressif’s ESP32-P4: a powerful application processor with dual-core 400 MHz and a single-core low power 40 MHz RISC-V processors. Interestingly it doesn’t appear to have the radios which have been a feature of previous ESP parts, but it makes up for those with a much more comprehensive array of peripherals.

Some details are beginning to emerge, whether from leaks or in preparation for launch, including the first signs of support in their JTAG tool, and a glimpse in a video from another Chinese company of a development board. We got our hopes up a little when we saw the P4 appearing in some Espressif documentation, but on closer examination there’s nothing there yet about the interesting new peripherals.

Looking at the dev board and the video we can see some of what the thing is capable of as it drives a large touchscreen and a camera. There are two MIPI DSI/CSI ports on  the PCB, as well as three USB ports and a sound codec. A more run-of-the-mill ESP32-C3 is present we think to provide wireless networking, and there’s a fourth USB port which we are fairly certain is in fact only for serial communications via a what our best blurry photograph reading tells us is a Silicon Labs USB-to-serial chip. Finally there’s large Raspberry Pi-style header which appears to carry all the GPIOs and other pins. We’ve placed the video below the break, if you see anything we’ve missed please tell us in the comments.

We first covered this chip back in January, and then as now we’re looking forward to seeing what our community does with it.

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The PhotonPower Zero board laying on a desk surface

PhotonPower Zero For Effortless Solar Pi Zero Projects

April 2, 2024 by 2 Comments

A Pi Zero doesn’t need much to sustain itself, and it’s projects like the PhotonPower Zero that remind us of it its low appetite when we need this reminder most. The PhotonPower Zero board lets you power a Pi Zero board from a solar cell, with a LiIon backup, and a microcontroller for power management. Created by [David Murray], this board’s been a perfect solution for quite a few projects of his, and now he is sharing the design so that we can create outdoor-suited devices as easily as he’s been able to.

Tested for months in Australian summer and winter conditions alike, the design pulls no punches and has everything you might need. Like any self-respecting power addon, it has a management microcontroller for going as low-power as you’d like, communicating the battery data to the Pi Zero, and being able to safely shut it down when needed. If you fancy what this board does, [David Murray] tells you all, both in the video and in the associated posts!

One of the best parts about this board is that it’s fully open-source – schematics, KiCad PCB source files, and even 3D designs are available in the GitHub repo. You could source all the parts right now and build a fleet of solar-powered Zeros, and if you want the hard parts to be done for you, there’s a Kickstarter campaign that lets you get a PhotonPower Zero board without self-assembly. We’ve covered similar boards before – powering a Pi Zero isn’t lost art, and, there’s a lot to learn from this project specifically. Such boards are especially tempting, given that the latest Pi Zero W 2 is the most efficient Pi Zero to date – outdoor-capable 24/7 powered devices with a fair bit of CPU have never been this close!

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A Supercapacitor From Mushrooms

April 1, 2024 by 28 Comments

The supercapacitor is an extremely promising energy storage technology, and though they have yet to reach parity with the best batteries in terms of energy density, offers considerable promise for a future of safe and affordable energy storage. Perhaps best of all from our point of view, they are surprisingly simple to make. A practical supercapacitor can be made on the bench by almost anyone, as the ever-resourceful [Robert Murray-Smith] demonstrates using mushrooms as his feedstock.

The idea of a supercapacitor is to replace the flat plate on the simple capacitor from your physics textbook with one that has as large a surface area as possible for charge to accumulate on. In this case the surface is formed from organic charcoal, a substance which retains something of the microscopic structure of whatever it was made from. Mushrooms are a good feedstock, because their mycelium structure has a naturally huge surface area. He takes us in the video below the break through the process of carbonizing them, much easier when you have a handy kiln than trying the charcoal-burner method, and then grinds them to a powder before applying them as a paste with a binder to a piece of graphite foil. With two of these electrodes and a piece of paper towel as a dielectric, he demonstrates a simple benchtop supercapacitor running a small electric motor for a surprisingly longer time than we expected.

We’d like to see further work on home made supercapacitors, as we believe they have immense potential as well as storing the stuff. Meanwhile, this is by no means the most unexpected supercapacitor material we’ve seen.

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Why Is My 470uF Electrolytic Cap More Like 20uF?

April 1, 2024 by 9 Comments
The simple capacitor equivalent circuit taught in school

Inductors are more like a resistor in series with an ideal inductor, resistors can be inductors as well, and well, capacitors aren’t just simply a capacitance in a package. Little with electronics is as plain and simple in reality as basic theory would have you believe. [Tahmid Mahbub] was measuring an electrolytic capacitor with an LCR and noticed it measuring 19 uF despite the device being rated at 470 uF. This was because such parts are usually specified at low frequencies, and at a mere 100 kHz, it was measuring way out of the specification they were expecting. [Tahmid] goes into a fair bit of detail regarding how to model the equivalent circuit of a typical electrolytic capacitor and how to determine with a bit more accuracy what to expect.

An aluminium electrolytic capacitor is more like this

The basic equivalent circuit for a capacitor has a series resistance and inductance, which covers the connecting leads and any internal tabs on the plates. A large-valued parallel resistor models the leakage through the dielectric in series with the ideal capacitance, which is responsible for the capacitor’s self-discharge property. However, this model is still too simple for some use cases. A more interesting model, shown to the left, comprises a ladder of distributed capacitances and associated resistances that result in a progressively longer time-constant component as you move from C1 to C5. This resembles more closely the linear structure of the capacitor, with its rolled-up construction. This model is hard to use in any practical sense due to the need to determine values for the components from a physical part. Still, it is useful to understand why such capacitors perform far worse than you would expect from just a simple equivalent model that looks at the connecting leads and little else.

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Fire Up The 3D Printer And Build Yourself A Spiderbot

April 1, 2024 by 12 Comments

Robots are cool, so check out [Atlin Anderson]’s Spiderbot (video, embedded below) which can be made with 3D printed parts, hobby servos, and ESP32-CAM module for control and a first-person view. Looking for a new project? All of the design details are shared online if you’d like to make a hexapod of your own.

We like the effort [Atlin] put into minimizing hardware fasteners in the design of the 3D-printed parts, and aiming for a modular concept that leaves things open for expansion or modification. There’s plenty of room in the chassis for more hardware, with a convenient peg system for snap-fitting assemblies.

Control is done wirelessly via a mobile phone with an app created using the MIT App Inventor, a fantastic tool that is still going strong as a capable and accessible way to make an Android app.

As for the ESP32-CAM module that drives it all, it is a great piece of hardware with capabilities that are leveraged very nicely here. We’ve seen other projects make good use of it as well, from this 1/64 scale micro RC car to an oddball tripod camera robot.

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The laptop in question, with the LCD-bearing top half printed in pink, and the bottom half showing off the Thinkpad keyboard.

Pinkpad, A DIY Laptop You Must Print In Pink

April 1, 2024 by 20 Comments

Looking to build a laptop all on your own? Check out the Pinkpad, a DIY laptop project that as if appeared out of nowhere, gives you a based on an off-the-shelf Dell motherboard. This build projects an aura of unabashed competence – the website brings you to a different universe, the documentation is as curt as it is extensive, and the build evidently works.

With a Thinkpad x61 keyboard, a reasonably modern (Dell Vostro 5481, Ryzen possible) motherboard embeddable inside, and a 10″ 1024×768 screen, this ~11″ laptop packs a certain kind of punch for what’s a build-it-yourself project. Most of the value of this design is in the 3D files – which were done in Google SketchUp, and the laptop is small enough that you could print its shell reasonably quickly. Not that you should follow the parts list religiously – the screen in particular might just warrant reconsideration in your eyes. On the other hand, we wish you all the luck on your SketchUp journey if you want to modify the shell. It also isn’t lost on us that the parts list doesn’t list a battery in it.

This is an impressive project to see open-sourced, and we hope it can inspire some hackers in the custom laptop building cohort. One prominent flaw of consumer-facing technology is that you can’t always get your devices in pink, and printing your laptop’s chassis yourself is a surefire way to combat this. If this laptop’s form-factor is too commonplace for you, we’ve seen no shortage of custom laptops grace our pages, from miniature ones to CRT luggable beasts, and click on the tags below if you’d like to see more!

We thank [Max_UA] for sharing this with us!

SatCat5: UART, SPI And I2C Via Ethernet With FPGA-Based Design

April 1, 2024 by 15 Comments
Arty A7-based prototype of SatCat5 with custom switch I/O board. (Credit: The Aerospace Corporation)
Arty A7-based prototype of SatCat5 with custom switch I/O board. (Credit: The Aerospace Corporation)

To the average microcontroller, Ethernet networks are quite a step up from the basic I2C, SPI and UART interfaces, requiring either a built-in Ethernet MAC or SPI-based MAC, with tedious translation between Ethernet and those other interfaces. Yet what if this translation could be done automatically and transparently?  This is what the SatCat5 FPGA-based project by [The Aerospace Corporation] aims to provide: a gateway akin to an unmanaged Ethernet switch that also supports those non-Ethernet links. Recently they answered a range of questions about the project on Hacker News.

The project name comes from the primary target audience: smallsat and cubesat developers, which is an area where being able to route more traffic over a common Ethernet-based bus is a major boon. The provided Xilinx Artix-7-based reference design (pictured) gives a good idea of how it can be used: it combines an Arty A7 development board with a custom PCB containing an Ethernet switch IC (SJA1105), TJA1100 transceiver, two RJ45 jacks and four PMOD connectors, here connected to two UARTs for bidirectional communication between them. Ethernet frame encapsulation is provided using the standard Serial Line Internet Protocol (SLIP), with more details covered in the FAQ. At a minimum an FPGA like a Lattice iCE40 is required, with an MCU capable of using the provided C++ libraries, or a custom implementation.

Thanks to [STR-Alorman] for the tip.