The Pi Pico board on top of a white box with an Ethernet jack, with a sensor module plugged onto the Pico's pin headers. A black MicroUSB and a green Ethernet cable are connected to this device.

An Elegant Ethernet Library For Your Next RP2040 Project

August 27, 2022 by Arya Voronova 17 Comments

A few days ago we covered a project that brought Ethernet connectivity to the Raspberry Pi Pico using little more than some twisted pair and a RJ-45 connector. It was a neat trick, but not exactly ready for widespread adoption. Looking to improve on things a bit, [tvlad1234] has taken that project’s code and rewritten it into a friendly library you can use with any RP2040 board.

In case you missed it, the initial demo did 10BASE-T transmission by bit-banging with the PIO, and was able to send UDP messages to devices on the wired LAN. It was an impressive accomplishment, but its code didn’t make it easy to build your project around it. This new library makes UDP messaging as easy as a printf, offloading all non-PIO-managed Ethernet signal work onto the RP2040’s second CPU core. The library even generates a random MAC address out of your flash chip’s serial number!

As a demonstration of the new library, [tvlad1234] has put together a simple Ethernet-connected temperature monitor using the BMP085 or BMP180 sensor connect over I2C. If you feel like you could use an Ethernet transmit-only sensor in your life, browsing the source code would be a great start.

Pi Pico Gives Its Life For Overclocking

August 25, 2022 by Al Williams 14 Comments

How fast can a Raspberry Pi Pico go? Well, apparently the answer is 1 GHz if you freeze it and give it over twice the voltage it normally gets. Oh, one catch. After a few minutes, the chip will fry itself.

That’s the results reported by [David] who took a Peltier cooler and a pretty serious over-voltage. The dhrystone scores went from around 200 to over 1100. Of course, there’s that pesky early death to worry about, so you probably won’t want to try this at home.

Even before the chip bites the dust, there are other problems to address. For example, once you get much over 250 MHz, the Pico’s SPI flash can’t keep up, so all the software you want to run has to be put in RAM first. You’ll also want to do some poking at the system clock parameters.

Honestly, we enjoy overclocking PCs or just about anything else. The good news is if you fry a Pico, it won’t make a sizable dent in your wallet. It is also a fun way to learn a bit more about the internals of the processor. According to [David], the cooler took the part to -40 C. We wonder how it would fare in a bath of LN₂?

Of course, you can push a regular Pi, too. If you really need a 1 GHz overclocked microcontroller, maybe check out the Teensy.

An ASCII Terminal Like It’s 1974

August 21, 2022 by Jenny List 10 Comments

It’s quite probable that any of you who have built a keyboard will have done so using a matrix of keys connected to a microcontroller, or if you are old-school, a microprocessor. A CPU can scan the keyboard matrix with ease, and pass whatever is typed either to whatever software it is running, or to a host computer. There was a time however when available CPUs were not considered powerful enough to do all this and also perform a useful task, so a keyboard would have its own decoder chip that would output ASCII over a parallel interface. It’s an era [John Calhoun] harks back to with Adam74, a little ASCII terminal which takes its input from that 7-bit parallel port.

In the place of a forest of TTL chips which might have graced the originals, within that attractive curved laser cut acrylic case is an LCD display and a Teensy microcontroller board. There’s a level shifter for the classic 5 volt logic, and of course a small buzzer for the essential BEL character. In these days when a parallel interface is relatively rare, he describes the rediscovery of alternate earth lines in a ribbon cable to minimize cross-talk. Should you wish to try your own, everything can be found on GitHub.

All in all it’s a fun way to rediscover an old idea.

Clover Computer: A Modern Z8000 CP/M Machine

August 21, 2022 by Chris Lott 20 Comments

Seeing some old Zilog 16-bit chips on eBay recently, [Scott Baker] was curious enough to snap them up and build himself a Z8000 computer. It started as a two-board solution, then he added a display module. Instead of layering the boards vertically à la a PC/104 stack, [Scott] decided to build them flat. His first backplane was triangular, but he opted for a square to accommodate one more expansion board in the future. The assembled contraption resembles a clover, hence the name Clover Computer.

The Z8000 was Zilog’s first 16-bit microprocessor, introduced in 1979. It was not hugely popular for a variety of reasons (the Z8000 Wikipedia article has some interesting details). The Z8000 was eclipsed in the marketplace by Intel’s 8088 and Motorola’s 32-bit 68000. One interesting point is that the Z8000 did not use microcode, and as a result, its transistor count was significantly less than its contemporaries. The Z8000 was used in some military applications, and despite its limited commercial success, it continued to be available from Zilog and licensed second sources up until 2012.

[Scott]’s design splits the system into a CPU board, a memory and serial board, and a display board. Along the way, he learns 1980’s era tricks from the Olivetti M20, one of the few computer systems designed around the Z8000. He also manages to find a recent Z8000 implementation of CP/M by GitHub user [4sun5bu], which [Scott] forked and adapted to his project (see project repo here). He succeeds in getting everything working, and ports a monitor, Tiny Basic, and Zork.

Check out his project write-up introductory link, and see it in action in the video below the break. Did you ever use or encounter the Z8000? Let us know in the comments!

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Every Frame A Work Of Art With This Color Ultra-Slow Movie Player

August 19, 2022 by Dan Maloney 15 Comments

One of the more recent trendy builds we’ve seen is the slow-motion movie player. We love them — displaying one frame for a couple of hours to perhaps a full day is like an ever-changing, slowly morphing work of art. Given that most of them use monochrome e-paper displays, they’re especially suited for old black-and-white films, which somehow makes them even more classy and artsy.

But not every film works on a monochrome display. That’s where this full-color ultra-slow motion movie player by [likeablob] shines. OK, full color might be pushing it a bit; the build centers around a 5.65″ seven-color EPD module. But from what we can see, the display does a pretty good job at rendering frames from films like Spirited Away and The Matrix. Of course there is the problem of the long refresh time of the display, which can be more than 30 seconds, but with a frame rate of one every two hours, that’s not a huge problem. Power management, however, can be an issue, but [likeablob] leveraged the low-power co-processor on an ESP32 to handle the refresh tasks. The result is an estimated full year of battery life for the display.

We’ve seen that same Waveshare display used in a similar player before, and while some will no doubt object to the muted color rendering, we think it could work well with a lot of movies. And we still love the monochrome players we’ve seen, too.

ESP8266 Smart Vents Keep Tabs On Home Temps

August 18, 2022 by Tom Nardi 50 Comments

Have you ever found that, despite having a central heating and air conditioning system, that not all the rooms in your home end up being the temperature you want them to be? Maybe the dining room gets too hot when the heater is running, or the bedroom never seems to cool off enough in the summer months. If that sounds like your house, then these motorized “smart vents” from [Tony Brobston] might be exactly what you need.

The idea here is pretty simple: an ESP8266 and a servo is built into the 3D printed vent register, which allows it to control the position of its louvers. When connected to your home automation system via MQTT, the vents allow you to control the airflow to each room individually based on whatever parameters you wish. Most likely, you’ll want to pair these vents with an array of thermometers distributed throughout the house.

While [Tony] says the design still needs some testing, he’s released smart vents in a range of sizes from 2×10 to 6×12 inches. He’s also provided excellent documentation on how to print, assemble, and program the devices. It’s clear that a lot of care and thought went into every element of this project, and we’re excited to see how it can be developed further by the new ideas and contributors that will inevitably pop up now that it’s gone public.

Want to add some automation to your HVAC, but don’t have a fancy central unit? Don’t worry, as long as your heater or air conditioner has an infrared remote, you should be able to wedge a WiFi-enabled microcontroller in into the equation.

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Chips Remembered: The Scenix/Ubicom/Parallax SX

August 17, 2022 by Al Williams 70 Comments

If you are a bibliophile, going to a used bookstore is a distinctly pleasant experience. Sure, you might discover an old book that you want to read. But at least some of the endorphin rush comes from seeing old friends. Not humans, but books you read years or even decades ago. Most often, you don’t buy the book — you probably have one stashed in a box somewhere. But it is a happy feeling to see an old friend and maybe thumb through it reading a passage or two among shelves of musty books. I wish we had something like that for chips. Outside of a few notable exceptions, chips tend to have a short life span of popularity and then give way to other chips. This is especially true of CPUs. One that I especially miss is the Scenix/Ubicom/Parallax SX chip.

I had a bookstore-like experience with this processor the other day. I produced a few products based around these chips and I have a small stash of them left. I jealously guard the hardware needed to program them “just in case.” Well, naturally, someone needed a few for some reason so I had to dig it all up. Knowing these might be some of the last of the unprogrammed SX chips in the world made me a little nostalgic.

The Story

In the late 1990s, a company called Scenix started producing a microcontroller called the SX in a few footprint sizes. So the SX18 was, for example, an 18-pin part. By 1999, they were already in full swing with the SX18 and SX28 and they introduced the SX52.

Of course, a lot of companies produced microcontrollers. The Scenix offering was a bit special. In those days, the Microchip PIC was the king of the hill. The PIC is an odd beast that evolved from a very limited controller made to be small and inexpensive. Notably, while it could support relatively high clock frequencies — 20 MHz was common — each normal instruction took 4 clock cycles. So when your crystal said 20 MHz, you were running instructions at 5 MHz.

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