The Benefits Of Critiquing Your Own PCB Designs

January 3, 2022 by 8 Comments

In a recent retrospective video, [Phil] from Phil’s Lab goes through a number of his early PCB designs, to critique and comment on what he likes and doesn’t like in these designs. Even though it’s only been a few a few years, he founds plenty that’s wrong. From poor and inconsistent formatting in the schematic, to sloppy and outright broken PCB layouts. It’s a fascinating look at years of lessons learned.

[Phil] comments on the importance of clear labeling and organization of sections and pages in the schematic to make it obvious what the function of a block is. Other lessons include the labeling of nets to make PCB routing a lot easier, making good use of PCB planes, getting all relevant information on components and layout in the schematic as a comment, and connecting decoupling capacitors to their relevant pins.

Although we tend to forget about older projects, it can be very interesting to take a look at them now and then, to see (hopefully) our progress over the years. In the case of [Phil] it’s fascinating to see the transition from a basic two-sided board with THT components to multi-layer boards with STM32 MCUs.

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Metal mechanoid security patrol ride-on made from scrap

Homemade Scrapyard Security Mech Gives Uncle Super Powers

January 3, 2022 by 26 Comments

[Handy Geng] is back again with another bonkers build, that we just can’t not cover. His Uncle came to visit the workshop one day and said he’d love to go there every day, and could even watch over it when [Handy Geng] was away. But being an older chap and needing a stick to get around, he would not be much use if ‘bad guys’ decided to pay a visit. The obvious solution was to build a ride-on security mech which Uncle could ride on, (video, embedded below) and use to defend the shop from bandits.

The build starts with him unloading a large pair of tracked wheel units from his truck, which caused a chuckle around these parts when we tried to imagine the scrap yard he’d just visited! The build video is more of a spot-weld-come-assembly log, with the less interesting sub assembly construction omitted. If he’d included all the details, this video would have been hours long. Though, we’d probably watch that anyway.

Features of the final construction include, but not limited to, dual motors for on-the-spot turns, night-time patrol lights, dual pneumatic fists for attack mode, dual water cannons for a more gentle approach and rear facing speakers blasting out Chinese opera for the ultimate deterrent. Practical touches include an integrated glasses case for the ready-readers, and a walking cane holder, so the mech was Uncle-ready. He seemed impressed from the grin on his face!

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Matrix Digital Rain On The IBM PC With A High Persistence Monitor

January 3, 2022 by 11 Comments

Unless you’ve been hiding under a rock for the last 20-odd years, you will have come across The Matrix series of movies, and the cool green ‘digital rain’ effect used frequently. This inspired [Oli Wright] to wonder what it would look like if instead of running the animation on a modern display, using a digitally produced phosphor persistence effect, it was implemented on some retro PC hardware, using an actual high-persistence phosphor Green Monochrome monitor. (Video embedded, below) As luck would have it, [Oli] owns a 40-year-old IBM PC 5150 as well as the matching IBM 5151 monitor, so it was a simple matter to implement the effect in 8088 assembler to create falling sequences of characters. The final binary is less than 256 bytes!

The IBM 5151’s long display persistence was intended to reduce the visibility of display flicker due to the low scan rate, but has the unfortunate side effect of smearing horribly when the image changes. This is exactly what [Oli] needed to implement this effect and we think it looks jolly fine.

[Oli] made use of the excellent PCjs browser-based emulator written by [Jeff Parsons] to demonstrate what the software is doing, without the effect being evident. If you like, you can try it out for yourselves, as the assembly listing is available on the project GitHub.

Of course, we’ve covered the digital rain effect many. many times before, for example, with this Arduino Library, and here’s a custom PC case side panel from way back in December 2021, if you can remember those days.

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TFT35 Dual Mode 3D Print Control – Hands On

January 3, 2022 by 18 Comments

I was rebuilding one of my 3D printers — again — and decided I needed a display upgrade. A color screen is nice, but there are some limitations. I also found there are ways around these limitations, so I wanted to share my thoughts on a dual-mode color touch screen LCD controller for your 3D printer. The screen in question is a TFT35 from BigTree Tech. It is similar to an MKS screen, but it can operate in two different modes, as you will see.

A few years ago, I picked up an Anet A8 which was very inexpensive, especially on sale. Not the best printer, though, because it has that cheap acrylic frame. No problem. A box full of aluminum extrusion later, the printer was reborn. Over time, I’ve completely reworked the extrusion system and the Y-axis, leaving only the motors, bearings, and the controller/display as the original.

That last part was what bothered me. The Anet board is actually pretty capable for a small cheap board. But it is just what the printer needs and nothing more. If you wanted to hack the printer there was very little memory left and only one spare pin for I/O. So it was time to replace the board and why not the controller, too?

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Another Homebrew Linux Board Success Story

January 3, 2022 by 26 Comments

It’s truly incredible what the hobbyist is now capable of. While it would have seemed all but impossible a few years ago, we’re happy to report that yet another dedicated hardware hacker has managed to spin up their own custom Linux single-board computer. Creator [Ian Kilgore] tells us the only goal when developing CATFOOD (yes, that’s the name) was to gain confidence with at-home board production, so it looks like a success to us.

To those who’ve been keeping an eye on this sort of thing, it will probably come as no surprise to hear [Ian] was inspired by the work of [Jay Carlson], who arguably kicked off this whole trend when he put together a bevy of homebrew Linux boards in an effort to compare different System-in-Package ICs. His incredibly detailed write-up of the experience and lessons learned along the way has emboldened other brave souls to take up the challenge.

The USB-C powered board uses an ARM i.MX 6ULL processor and features DDR3, NAND flash, and an Ethernet interface. That last one was the biggest deviation from the reference design, which meant it took a little fiddling to get right. For anyone playing along at home, [Ian] collected up the lessons learned while developing CATFOOD, bringing the whole learning experience full circle.

If you’re interested in more homebrew Linux SBCs, we’d highly recommend reading up on the WiFiWart developed by [Walker]. Over the course of about six months, we got to watch the open hardware board go from concept to a diminutive first prototype.

2021: As The Hardware World Turns

January 3, 2022 by 15 Comments

Well, that didn’t go quite as we expected, did it? Wind the clock back 365 days, and the world seemed to be breathing a collective sigh of relief after making it through 2020 in one piece. Folks started getting their COVID-19 vaccines, and in-person events started tentatively putting new dates on the calendar. After a rough year, it seemed like there was finally some light at the end of the tunnel.

Turns out, it was just a another train. New variants of everyone’s favorite acute respiratory syndrome have kept the pandemic rolling, and in many parts of the world, the last month or so has seen more new cases of the virus than at any point during 2020. This is the part of the Twilight Zone episode were we realize that not only have we not escaped the danger, we didn’t even understand the scope of it to begin with.

Case in point, the chip shortages. We can’t blame it entirely on the pandemic, but it certainly hasn’t helped matters. From video game systems to cars, production has crawled to a standstill as manufacturers fight to get their hands on integrated circuits that were once plentiful. It’s not just a problem for industry either, things have gotten so bad that there’s a good chance most of the people reading this have found themselves unable to get their hands on a part or two these last few months. If you were working on a hobby project, it’s a temporary annoyance. But for those who planned on finally bringing their latest big idea to market, we’ve heard tales of heartbreaking delays and costly redesigns.

It would be easy to look at the last twelve months and see nothing but disappointment, but that’s hardly the attitude you want to have at the beginning of the year. So let’s take the high road, and look back on some of the highlights from 2021 as we turn a hopeful eye towards the future.

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Need A Small, Cheap Ammeter? Blinkenlights To The Rescue!

January 3, 2022 by 3 Comments

You know how it is. You’ve got that new project running, and while it doesn’t consume much power, it also doesn’t give much indication of whether it’s functioning or just sitting there with a dead battery. What you need is an ammeter to check power consumption, even from across the room. And it just so happens that [Manuka] has Just The Circuit You Need, complete with a demonstration in the video after the break!

Oh sure, you could grab a cheap ammeter at your favorite tool import store or site, but those are bulky and take batteries. You could put in an LED that gets dimmer as voltage drops. But wait- is that the sun shining on it? or is it on? Or has something gone awry and it’s consuming too much power?

What [Manuka] gives us is a circuit that is designed to be built into your project or project’s power supply. Using only an ultra-bright white LED, red blinking LED, PNP transistor, and a diode, the circuit gives a strong visual indication of current consumption by blinking brighter and more frequently as current increases. With a bit of calibration, accurate measurements can be obtained. All of this is made possible by using the Flashing LED as a driver for the ultra-bright LED, which is a pretty slick hack!

Flashing LEDs have a great number of uses, like protecting your family from lions. Yes, really. Got a cool tip for flashing LEDs, blinkenlights, 555’s, or any odd thing that strikes your hackers fancy? Let the tip line know!

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