RPDot: The RP2040 Dev Board Barely Bigger Than The Chip

August 25, 2023 by Dan Maloney 33 Comments

Is [William Herr]’s RPDot actually the world’s smallest RP2040 dev board? We can’t say for sure, but at 10 mm on a side, we’d say it has a pretty good shot at the record.

Not that it really matters, mind you — the technical feat of building a fully functional dev board that’s only 3 mm longer on each side than the main chip is the kind of stuff we love to see. [William] says he took inspiration from the [SolderParty] RP2040 Stamp, which at one inch (25.4 mm) on a side is gigantic compared to the RPDot. Getting the RP2040 and all the support components, which include an 8MB QSPI Flash chip, a 3V3 LDO, a handful of 0201 passives, and even a pair of pushbuttons, required quite a lot of design tweaking. He started his PCB design as a four-layer board; while six layers would have made things easier, the budget wouldn’t allow such extravagance for a prototype. Still, he somehow managed to stuff everything in the allotted space and send the designs off — only to get back defective boards.

After reordering from a different vendor, the real fun began. Most of the components went on the front side of the board and were reflowed using a hot plate. The RP2040 itself needed to go on the back side, which required gentle hot air reflow so as not to disrupt the other side of the board. The results look pretty good, although those castellated edges look a little worse for the wear. Still, for someone who only ever worked with 0402 components before, it’s pretty impressive.

[William] says he’s going to open-source the designs as well as make some available for sale. We’ll be looking out for those and other developments, but for now, it’s just pretty cool to see such SMD heroics.

Adding MMIO RAM On The RP2040

August 21, 2023 by Matthew Carlson 19 Comments

[Dmitry Grinberg] is an adept tinkerer who wanted a much larger RAM space on his Raspberry Pi 2040 (RP2040) than the measly 264kb on-board SRAM. The chip does support 16MB of off-flash memory via a QSPI bus, but this must be accessed explicitly rather than being memory mapped. With clever trickery involving XIP (Execute in Place), Dmitry mapped 8MB of external QSPI RAM into the address space.

XIP mode allows the chip to fetch data on-demand from an external chip and place it into RP2040 caches mapped at 0x10xxxxxx. The RP2040, although incredibly versatile, has a limitation – it can only perform read and execute operations in its XIP mode. The first step to solving this was to get data from persistent storage to RAM on boot. Armed with a dual-OR gate IC, an inverter, and two resistors, [Dmitry] can toggle the nCS pin that selects between flash and RAM. A first-stage bootloader copies the program from flash to RAM, then sets up XIP mode and launches into a second-stage loader.

Continue reading “Adding MMIO RAM On The RP2040” →

GrblHAL CNC Controller Based On RP2040 Pico

August 11, 2023 by Chris Lott 18 Comments

[Phil Barrett] designed a new CNC controller breakout board called the PicoCNC which uses the Raspberry Pi Pico RP2040 module and grblHAL. It packs a bunch of features typical of these controllers, and if you use the Pico W, you get WiFi connectivity along with USB. And if you don’t want connectivity, you can execute G-code directly from a micro SD card. The board is available in kit form, and schematics are posted on the GitHub repository above. Some of the features include four axes of motion, spindle control, limit switches, relay drivers, expansion headers, and opto-isolation.

This isn’t [Phil]’s first controller board. He also designed the grblHAL-based Teensy CNC controller breakout board, a step up from the usual Arduino-based modules at the time and boasting Ethernet support as well. According to the grblHAL site, nine different processors are now supported. There are well over a dozen CNC controller breakout boards listed as well. And don’t forget [bdring]’s 6-Pack grbl-ESP32 controller, a modular breakout board we covered a few years back. So pick your favorite board or roll your own and get moving.

Running DOOM In A Keycap Takes Careful Work

August 9, 2023 by Donald Papp 4 Comments

Shoehorning DOOM into different hardware is a classic hacker’s exercise, and [TheKeebProject] managed to squeeze the 1993 classic into a custom keycap with the help of a Raspberry Pi RP2040, a custom PCB, and a clear resin enclosure. It even has a speaker for sound!

All processing is done inside the keycap, which is a clever feat. There is a USB connection, but it’s only for power and keyboard controls, so it’s completely playable without needing a whole lot of external support. The custom PCB and code are based off an earlier RP2040 DOOM project, and [TheKeebProject] has certainly made it their own by managing to get everything so tightly integrated. There’s a quick video mashup embedded below. There’s still a bit of work to do, but the code and design files are all on GitHub should you wish for a closer look.

Making DOOM physically smaller is a good challenge, but we’d like to remind fans that we’ve also seen DOOM shrink in terms of power consumption, all the way down to 1 mW.

Continue reading “Running DOOM In A Keycap Takes Careful Work” →

A Game Boy Camera, Without The Game Boy

July 29, 2023 by Jenny List 3 Comments

We all know the Nintendo Game Boy camera peripheral, and we’ve seen plenty of hacks for it on these pages over the years. We like [Raphael Boichot]’s camera then, as instead of including a Game Boy or emulating one, it talks directly to the sensor from an RP2040. The result is a standalone camera with slightly better quality than the original, and with near-limitless storage and easy retrieval of pictures.

For us the interesting revelation from this project comes in the light it sheds on the sensor module, the Mitsubishi M64282FP, but it’s no slouch as a camera beside that. There are motion sensor and timelapse modes, as well the ability to take high dynamic range pictures, and as if that’s not enough it also has all the tweakable things you’d expect from a “proper” camera. The oldest adage in photography is that the best camera in the world is the one in your hand, and we’d say that this one’s better than a real Game Boy Camera should the once-in-a-lifetime picture come while you’re holding it.

Of course, a better Game Boy camera needs a better lens, right?

A PCB with an OLED display, a screw terminal block and a Raspberry Pi Zero board

Hackaday Prize 2023: Pi Pico Measures Volts, Amps And Watts

July 16, 2023 by Robin Kearey 6 Comments

Measuring a voltage is pretty easy: just place your multimeter’s probes across the relevant pins and read the value. Probing currents is a bit trickier, since you need to open up the circuit and place your probes in series. Checking a circuit’s power consumption is the hardest, since you need to measure both voltage and current as well as multiply them at each moment in time. Fed up with having to hook up two multimeters and running a bunch of synchronized measurements, [Per-Simon Saal] built himself an automatic digital power meter.

The heart of this instrument is an INA219 chip, which can measure and digitize voltage and current simultaneously. It outputs the results through an I2C bus, which [Per-Simon] hooked up to a miniaturized version of the Raspberry Pi Pico called an RP2040-Zero. A screw terminal block is provided to connect the system to the device under test, while a 0.96″ OLED display shows the measured voltage, current and power.

The maximum voltage that can be measured is 26 V, while the current range is determined by the shunt resistor mounted on the board. The default shunt is 0.1 Ω, resulting in a 3.2 A maximum current range, but you can get pretty much any range you want by simply mounting a different resistor and changing the software configuration. In addition to displaying the instantaneous values, the power meter can also keep a log of its measurements – very useful for debugging circuits that use more energy than expected or for measuring things like the capacity of a battery.

There are lots of ways to measure electric power, but they all boil down to multiplying current and voltage in some way. The multiplication was done magnetically in the old days, but modern meters like [Per-Simon]’s of course use digital systems. Some can even plug directly into a USB port. If you want to measure mains power, transformers are an essential component for safety reasons.

PicoDebugger Makes Development Easier

July 12, 2023 by Lewin Day 12 Comments

Debugging a Raspberry Pi Pico is straightforward enough; it simply involves hooking up something up to the USB and SWD pins. [Mark Stevens] whipped up the PicoDebugger to make this job easier than ever before.

The Raspberry Pi Foundation developed the Picoprobe system to allow a RP2040 to act as a USB to SWD and UART bridge for debugging another Pico or RP2040. The problem is that hooking it up time and time again can be fussy and frustrating.

To get around this, [Mark] whipped up the PicoDebugger board, which directly connects most of the important pins for you. Drop a Pico into the “Target” slot, and you can hook up the PicoDebugger to its UART lines with the flick of a DIP switch. The SWD pins can then also be connected via jumpers if so desired. It also features a 2×20-pin header to allow the target to be wired into other hardware as necessary.

It’s a neat project, and it certainly beats running a bird’s nest of jumper wires every time you want to debug a Pico project. Simply dropping a board in is much more desirable.

We’ve seen some other neat debug tools over the years, too. If you’ve got your own development productivity hacks in the works, don’t hesitate to let us know!