This Parametric Project Box Generator Is Super Easy

January 31, 2022 by Dave Rowntree 8 Comments

When it comes to taking an idea from concept to prototype reality, depending on the type of project, there can be quite a few sub-tasks along the way. Take for example, your latest electronic widget design. You’ve finished the schematic, and the PCB layout is a work of art (if you do say so yourself) but having that kicking around on the desk unprotected with wires dangling is not the end game. Now you’ve got to make an enclosure of some kind, and I don’t know about you, but this is the bit where this scribe struggles a little to get something to fit nice. Even if you’ve got the latest 3D printer dialed in to within a gnat’s whisker of perfection, you’ve still got to come up with the design, and those dimensions need to be really accurate. So, for those of us who are great at the PCB, but suck at the enclosure, [Willem Aandewiel] has been busy making the tool just for you, with his PCB-orientated Yet Another Parametric Projectbox generator (YAPP.)

Defining the PCB mounting points w.r.t. the PCB outline

Without hesitation you can head over to the YAPP GitHub, grab that sweet OpenSCAD code, and get cracking with the demos. Provided for your convenience are a number of examples for enclosing some common items, such as Arduinos and ESP32 modules, so you can use those as a springboard to get your own code in place. YAPP works based off the PCB — by specifying programmatically since this is OpenSCAD — outer dimensions, mounting post locations first. Next you define openings in the six faces of the box, and the tool happily spits out a platter with the base and lid ready to drop into Cura (or your slicer of choice) What could be easier?

And before you start on non-rectangular designs, this is a rectangular box generator for rectangular PCBs. That is all this is designed for, and as far as we can tell, it does that one job well.

Of course, this is by no means the first enclosure generator to grace these pages, far from it. Here’s one for starters. If you’re here for tips to help make better designs, check this out, and finally 3DHubs also has a nice guide for you. Happy printing!

Remoticon 2021 // Voja Antonic Makes You A Digital Designer

January 27, 2022 by Dave Rowntree 10 Comments

[Voja Antonic] has been building digital computers since before many of us were born. He designed with the Z80 when it was new, and has decades of freelance embedded experience, so when he takes the time to present a talk for us, it’s worth paying attention.

For his Remoticon 2022 presentation, he will attempt to teach us how to become a hardware expert in under forty minutes. Well, mostly the digital stuff, but that’s enough for one session if you ask us. [Voja] takes us from the very basics of logic gates, through combinatorial circuits, sequential circuits, finally culminating in the description of a general-purpose microprocessor.

A 4-bit ripple-carry adder with additional CPU flag outputs

As he demonstrates, complex digital electronics systems really are just built up in a series of steps of increasing complexity. starting with individual active elements (transistors operating as switches) forming logic elements capable of performing simple operations.

From there, higher level functions such as adders can be formed, and from those an ALU and so on. Conceptually, memory elements can be formed from logic gates, but it’s not the most efficient way to do it, and those tend to be made with a smaller and faster circuit. But anyway, that model is fine for descriptive purposes.

Once you have combinatorial logic circuits and memory elements, you have all you need to make the necessary decoders, sequencers and memory circuits to build processors and other kinds of higher complexity circuits.

Obviously forty minutes isn’t anywhere nearly enough time time to learn all of the intricacies of building a real microprocessor like the pesky details of interfacing with it and programming it, but for getting up the learning curve from just a knowledge of binary numbers to an understanding of how a CPU is built, it’s a pretty good starting point.

Now, If you can only tear your eyes away from his slick game-of-life wall mounted LED display, you might pick up a thing or two.

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Reverse Engineering: Trash Printer Gives Up Its Control Panel Secrets

January 25, 2022 by Dave Rowntree 7 Comments

Many of us hardware-oriented types find it hard to walk past a lonely-looking discarded item of consumer electronics without thinking “If only I could lug that back to the car and take it home to play with” and [phooky] from NYC Resistor is no stranger to this sentiment. An old Epson WF-2540 inkjet printer was disassembled for its important ‘nutrients,’ you know, the good stuff like funky motors, encoders and switches. But what do you do with the control panel? After all, they’re usually very specific to the needs of the device they control, and don’t usually offer up much scope for reuse.

The RP2040 PIO is quite capable of pushing out those LCD pixels

[phooky] doesn’t usually bother with them, but this time decided to have a crack at it for fun. Inside, nothing out of the ordinary, with a large single-sided PCB for the key switches and LEDs, and a small PCB hosting the LCD display. The easy part was to figure out how the keyboard scanning was done, which turned out to be pretty simple, it just uses some 74-series shift register devices to scan the columns and clock out the row lines. A Raspberry Pi Pico module was pressed into service to scan the keyboard and enable a keyboard map to be created, by pure brute-force. No need to trace the circuit.

Things got interesting when [phooky] started looking into the LCD interface, based on the Epson E02A46EA chip (good luck finding a datasheet for that one!) and quickly realised that documentation simply wasn’t available, and it would be necessary to do things the hard way. Poking around the lines from the main CPU (an Epson E01A9CA , whatever that is) the display clock was identified, as well as some control signals, and three lines for the RGB channels. By throwing a Saleae data capture into some ROM exploring software, the display configuration was determined to be a standard 320×120 unit.

The PIO unit of the RP2040 was used to generate the video waveforms and push the pixels out to the LCD controller, allowing the RP2040 board to be wired inside the case permanently, converting the control panel into a USB device ready for action!

Want to know a little more about reverse engineering junk (or not) items and repurposing them to your will? Checkout this hacking piece from a couple of weeks back. For something a little more advanced, you could try your hand at a spot of car ECU hacking.

Thanks [Perry] for the tip!

Rainwater Storing Gojo Is A Stroke Of Genius

January 24, 2022 by Dave Rowntree 57 Comments

A traditional Ethiopian Gojo. Image courtesy of easterntravelandtour.com

The traditional Ethiopian Gojo is a circular domed dwelling constructed from a central vertical beam, and a surrounding structure of curved beams made from wood or bamboo. A covering of dried grass and mud completes the outer structure. These buildings are found everywhere in rural areas, due to their ease of construction, and availability of cheap materials. One major problem living in rural areas in developing countries is access to water. Ethiopian inventor [Anteneh Gashaw] knows a thing or two about the practicalities of living in a developing nation, and has come up with an ingenious take on the traditional Gojo. The idea is to replace the outer structure with pipes capable of storing rainwater. A collector plate on the top of the roof directs rain water into the pipes — with some small balancing tubes connecting them at the bottom — distributing the stored water evenly. A tap at the bottom of structure allows the pipes to be emptied on demand. Another interesting point about this design, is that the water adds some extra weight, for free, which gives the structure much improved stability in high winds, increasing safety.

{Anteneh] notes that proper water infrastructure is incredibly expensive, and just simply won’t happen. Well digging, installation of underground water tanks, and other such stop gap measures are great, but still need significant investment, and he believes that his modified Gojo idea will help reduce the problem of storing water during the rainy season, and reduce the pressure on centralised wells and other such community-orientated solutions. What’s more, it should be cheap. We shall watch with interest where this goes.

We’ve seen a few hacks from Africa nations, not many, just a few, but they are interesting ones. Like this DIY Helicopter that didn’t quite get to fly, and this e-waste 3D printer. We’ll keep our eye peeled for more!

Silicone Devices: DIY Stretchable Circuits

January 23, 2022 by Dave Rowntree 12 Comments

Flexible circuits built on polyimide film are now commonplace, you can prototype with them at multiple factories, at a cost that is almost acceptable to your average hacker. Polyimide film is pretty tough for something so thin, but eventually it will tear, and with larger components, bend radii are quite restricted. But what about stretchable circuits, as in circuits you can flex, twist and stretch? Let us introduce silicone devices. A research group from Hasselt University, Belgium, have been prototyping making truly flexible, silicone-based circuit substrates, managing to integrate a wide range of SMT component types with a dual layer interconnect, with vias and external contacts.

It should be possible to reproduce the process using nothing more special than your average Makerspace CO₂ laser cutter, and a couple of special tools that can be easily made — a guide for that is promised — it is purely a matter of gathering a few special materials, and using off-cuts you have lying around for the rest. The interconnect uses Galinstan, which is a low melting point alloy of gallium, indium, and tin. Unfortunately, this material is fairly expensive and cannot be shipped by air due to the gallium content, without specialised handling, at considerable expense. But that aside, other than some acrylic sheets, some vinyl, copper foil and a few sprays, nothing is beyond reach.

The construction process is reverse to what we normally see, with the components and copper contact plates placed first, on to a primed vinyl sheet. This sheet is laser marked with the component outlines to enable them to be corrected placed. Yes, that’s right, they’re using a laser cutter to mark vinyl, a chlorine-containing plastic. Hold on to that thought for a bit.

Insulating layers and substrate layers are constructed by blade-coating with a layer of clear silicone. Interconnect layers are formed by sticking a fresh vinyl sheet onto the exposed contacts and laser cutting just though it to expose the pads and the interconnect traces. Next the fancy Galinstan is applied by brush and the vinyl stencil removed. Rinse and repeat for the next layer of insulating silicone, more circuit traces, then use the laser cutter to precisely etch through the via regions to allow more metalisation to be added. Finally a coating of silicone is applied over the whole assembly, the laser is again used to etch the silicone away from the contact pads, and with a little solder tinning of these, you’re done. Simple, if only our Makerspaces didn’t have rules against laser cutting vinyl.

This was clearly a very brief overview, here is a very detailed instructables guide ready for you, as well as a formal research paper, detailing why this came about and why you might want to try this yourself.

If you’re into custom wearables, you might remember this earlier piece about silicone circuits, and this one weird organic-looking thing from the same time-frame.

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Hacked DSP5005 unit showing amp-hours screen

Another DPS5005 Alternative Firmware

January 22, 2022 by Dave Rowntree 9 Comments

These cheap Chinese-built programmable power supplies are nothing new, we’ve been using them for years. They’re not particularly good power supplies, since current feedback is in software, but for some tasks they’re a great fit and you can’t argue with the price. Alternative firmware projects have also been a thing for a while too, but none we’ve seen have been quite as capable and polished as this latest DPS firmware project by [Profi-max.] We’ve not come across the source code yet, but at least the binary image is freely downloadable.

The firmware has some interesting features, such as programmable pre-sets intended for battery charging applications. In fact, there is a dedicated battery charge mode screen. We want to warn, however, that charging lithium ion batteries with this might not be at all wise, not in the least because of a lack of protection hardware in place. It would be very easy to destroy the unit or overheat a battery this way! However, if you must do this, there are a few features to help you out, such as a handy ‘counters’ screen showing approximate charge delivered.

Remote programmability is, as usual, via the easily hacked in serial port, with firmware support for Bluetooth serial modules if wired USB serial doesn’t suit. For those who like to mount things differently, the screen can be rotated by holding a key on power-up, or if you hook up a MPU6050 accelerometer/gyro module it will even do it automatically!

To update a stock DPS unit, the only requirements are access to an ST-Link compatible programmer dongle, to target the STM32 SWD programming interface, and the STM32CubeProgrammer utility. Open source alternatives to that are also available, stlink comes to mind as a good option. Once you have the module PCB popped out of its plastic casing, only three wires need tacking onto a handy set of pads to complete the connection to the programmer dongle. Pretty simple stuff.

If you’re looking for a similar project, with source immediately available, then checkout the OpenDPS project we covered a few years ago, and if you’re thinking of going crazy, building a DIY open source electronics lab, we got you covered.

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A DIY CAD Mouse You Can Actually Build

January 18, 2022 by Dave Rowntree 50 Comments

When you spend a lot of time on the computer doing certain more specialised tasks (no, we’re not talking about browsing cat memes on twitter) you start to think that your basic trackpad or mouse is, let’s say, lacking a certain something. We think that something may be called ‘usability’ or maybe ease-of-use? Any which way, lots of heavy CAD users gush over their favourite mouse stand-ins, and one particularly interesting class of input devices is the Space Mouse, which is essentially patented up-to-the-hilt and available only from 3DConnexion. But what about open source alternatives you can build yourselves? Enter stage left, the Orbion created by [FaqT0tum.] This simple little build combines an analog joystick with a rotary knob, with a rear button and OLED display on the front completing the user interface.

The idea is pretty straightforward; you setup the firmware with the application you want to use it with, and it emits HID events to the connected PC, replacing the mouse or keyboard input. Since your machine will take input from multiple sources, it doesn’t replace your mouse, it augments it. It may not be very accurate for detailed PCB layout work, but for moving around in a 3D view, or dialling in a video edit, this could be a very useful addition to your workstation, so why not give it a try? The wiring is simple, the parts easily found and cheap, and it’s only a few printed parts! This scribe is already printing the plastics right now, if you listen carefully you might be able to make out the sound of the Lulzbot in background.

There are many other takes on this idea, with varying levels of complexity, like this incredible build from [Ahmsville] that sadly doesn’t make the PCBs available openly, and here’s one we covered earlier mashing the expensive 3DConnexion spacemouse into a keeb.

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