A Nicer Controller For Cheap Power Supply Modules

October 25, 2023 by Lewin Day 3 Comments

These days, you can get all kinds of cheap power supply modules off a variety of online vendors. A lot of examples from brands like Juntek and Drok often have pretty poor interfaces though, with a couple of tactile buttons and a simple 7-segment display. [rin67630] decided to whip up a better controller with a much more informative display.

The controller is designed to work with programmable buck converter modules like the DPS3806, Buck3603, and BST900. It’s based on a TTGO ESP32 with an integrated color TFT LCD. It displays voltage at the input and output, the same for current, along with current setpoints. It also allows for control of a fan and charge cycles if so desired, and it has the ability to fetch time from an NTP server for proper scheduling. There’s also a web interface complete with graphs for really diving down into the nitty-gritty. Future plans include adding an MPPT solar charging capability.

If you’ve ever wanted a cheap power supply module with really low-level control and rich data display, this could be just what you need. Meanwhile, you’ve got your own neat power supply in the works, don’t hesitate to drop us a line.

Level Your Trailer Or RV With This Nifty Helper Device

October 25, 2023 by Lewin Day 30 Comments

Getting your RV or trailer parked nice and level is key to getting a good night’s sleep. Traditional methods involve bubble levels and trial and error, but [MJCulross] wanted something better. Enter the Teensy RV Leveling Helper.

The device uses an accelerometer to detect the pitch and roll angles of the RV. It then displays these on a small screen, and performs calculations on how much the RV must be raised at each corner to bring it level. The RV’s width and wheelbase can be entered via a simple touchscreen interface to ensure the calculations are correct. There’s also a trailer mode which calculates three-point leveling figures for the wheels and the hitch, as opposed to the four-wheeled RV mode.

The result is that the correct leveling blocks can be selected first time when parking up the RV or trailer. It’s a lot less tedious than the usual method of parking, leveling, checking, and then leveling again.

We don’t see a lot of camper hacks around here, but we’ve noticed a new trend towards lightweight cycle campers in recent years. If you’ve found your own nifty hacks for your home on the open road, don’t hesitate to let us know!

Compact, Gesture-Based Remote Control Over Bluetooth

October 14, 2023 by Donald Papp 5 Comments

[AlexMiller11] shared a project for a DIY gesture-sensing remote control that acts like a Bluetooth keyboard, capable of controlling media and presentations on a computer with a high degree of accuracy.

The device recognizes eight different gestures and controls a host PC over Bluetooth.

The hardware is a Silicon Labs xG24 dev kit, a small IoT-focused board able to be powered by a CR2032 cell. Part of what makes it all work is the six-axis IMU sensor, but the rest is the software to interpret that data and figure out what motions the user is trying to do. That happens with a Neuton.AI model and SDK, a tiny but effective machine learning framework for small devices.

How does it actually work? The device acts as a Bluetooth HID, and gets connected to a PC in the same was as a regular Bluetooth keyboard. Once that’s done, recognized gestures are printed out the serial port as well as sent via Bluetooth to the host machine. Media can then be played, paused, volume adjusted, presentations controlled, and more. More details are on the project’s GitHub repository. There’s also a demo video that explains exactly what’s going on, embedded below the page break.

Machine learning is a way of using software to solve the kinds of problems humans are not very good at writing programs to solve, and accurate gesture recognition is a good example. Not all such applications require heaps of overheating GPUs, either. We’ve seen the concept of a neural network stripped down to its bare essentials running on an Arduino Uno, for those who would like to better appreciate the fundamentals.

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This 3D Printable Soldering Air Filter Really Sucks

October 14, 2023 by Kristina Panos 24 Comments

If you solder (and we know you do), you absolutely need ventilation, even for that lead-free stuff. Fortunately, [tinyboatproductions] has gotten into air quality lately and is here to help you with their snappy 3D printed air-filtering design.

At the heart of this build is a 120 mm notoriously-quiet Noctua fan coupled with a carbon filter. It does what you’d think — position the fan the right way and it sucks the air through the filter, which catches all those nasty particles.

The only problem is that the Noctua uses PWM, so there’s no governing it with a just potentiometer. To get around this, [tinyboatproductions] introduced an Arduino Nano and a buck converter, both of which were admittedly a bit overkill. Now the speed can be controlled with a pot.

Once control of the fan was sorted, [tinyboatproductions] decide to add an OLED display to show the fan speed and power condition, which is a nice touch. Be sure to check out the build video after the break.

If this doesn’t have quite enough features for you, here’s one that’s battery powered.

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How Not To Build An RP2040 Board

October 11, 2023 by Al Williams 26 Comments

We love that these days you can buy ready-made microcontroller boards that are very capable. But sometimes you need to — or just want to — do it yourself. Unfortunately, you really should design everything twice: once to figure out where all the problems are, and the second time to do it better. If you want to create your own board for the RP2040 then you are in luck. [Jeremy] has made the first (and second) iteration or an RP2040 board and shares with us what he would not do again.

In all fairness, he also has a blog post talking about what he did, so you might want to start there. However, we think his most valuable advice was his final word: Don’t fail to get started on your design. The longest journey, after all, begins with the first step.

His other advice is good, too. For example, don’t plug your new board into a computer because an error in the power supply could take the whole computer out. He also warns you not to do like he did and forget to order the $10 solder stencil with the PCBs.

Some of it is just good advice in general. For example — buy more small components than you think you need. There’s nothing worse than needing three resistors, having three resistors, and then watching one of the three fly across the room or stick to your soldering iron and melt into a pool of slag. Buy ten and you’ll save money in the long run.

In the end, the board did work and what he learned might help you if you decide to tackle a similar project yourself. [Jeremy’s] board is fairly large, but if you have an appetite for something smaller, check out the RPDot or the RP2040 Stamp.

Tiny Linux On A No-MMU RISC-V Microcontroller

October 11, 2023 by Jenny List 21 Comments

In the vast majority of cases, running a Linux-based operating system involves a pretty powerful processor with a lot of memory on hand, and perhaps most importantly, a memory management unit, or MMU. This is a piece of hardware which manages virtual memory, seamlessly giving each process its own memory sandbox in which it shouldn’t be able to rain on its neighbours’ parade. If there’s no MMU all is not lost though, and [Uros Popovic] gives us a complete guide to building the MMU-less μClinux on a RISC-V microcontroller.

The result is something of a Linux-from-scratch for this platform and kernel flavour, but it’s so much more than that aside from its step-by-step explanation. It’s probable that most of us have heard something of μClinux but have little direct knowledge of it, and he leads us through its workings as well as its limitations. As examples, standard ELF binaries aren’t suitable for these systems, and programmers need to use memory-safe techniques.

Whether or not any of you will run with this guide and build a tiny MMU-less Linux system, anything which expands our knowledge on the subject has to be a good thing. it’s not the first time we’ve seen a RISC-V microcontroller turned to this task, with a nifty trick to get round the limitations of a particular architecture.

Pocket CO2 Sensor Doubles As SMD Proving Ground

October 10, 2023 by Tom Nardi 4 Comments

While for some of us it’s a distant memory, every serious electronics hobbyist must at some point make the leap from working with through-hole components to Surface Mount Devices (SMD). At first glance, the diminutive components can be quite intimidating — how can you possibly work with parts that are literally smaller than a grain of rice? But of course, like anything else, with practice comes proficiency.

It’s at this silicon precipice that [Larry Bank] recently found himself. While better known on these pages for his software exploits, he recently decided to add SMD electronics to his repertoire by designing and assembling a pocket-sized CO2 monitor. While the monitor itself is a neat gadget that would be worthy of these pages on its own, what’s really compelling about this write-up is how it documents the journey from SMD skeptic to convert in a very personal way.

A fine-tipped applicator will get the solder paste where it needs to go.

At first, [Larry] admits to being put off by projects using SMD parts, assuming (not unreasonably) that it would require a significant investment in time and money. But eventually he realized that he could start small and work his way up; for less than $100 USD he was able to pick up both a hot air rework station and a hotplate, which is more than enough to get started with a wide range of SMD components. He experimented with using solder stencils, but even there, ultimately found them to be an unnecessary expense for many projects.

While the bulk of the page details the process of assembling the board, [Larry] does provide some technical details on the device itself. It’s powered by the incredibly cheap CH32V003 microcontroller — they cost him less than twenty cents each for fifty of the things — paired with the ubiquitous 128×64 SSD1306 OLED, TP4057 charge controller, and a SCD40 CO2 sensor.

Whether you want to build your own portable CO2 sensor (which judging from the video below, is quite nice), or you’re just looking for some tips on how to leave those through-hole parts in the past, [Larry] has you covered. We’re particularly eager to see more of his work with the CH32V003, which is quickly becoming a must-have in the modern hardware hacker’s arsenal.

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