Category Archives: Electronics

Posts about electronics. Usually meaning electrical gadgets smaller than a proper computer.

Macintosh SE Health Check

I had my dear old Macintosh SE out for a health check as I slowly extract my vintage computer collection from the (unconditioned) place I’ve been keeping it at my parents house to the basement of the place I’m renting. It had a couple interesting findings that seem worth putting online, including another floppy drive rebuild and a slightly elaborate fan replacement.

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Why did a Banggood package I ordered on March 26 just appear in Bahrain on July 5, the same day it finally showed “Shipment picked up?” Did it just get packed into a container and loaded on whatever outgoing vessel … Continue reading

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Anycubic Linear Kossel: Unofficial Owner’s Guide

Anycubic Kossel on its stand

I’ve been working with a number of Anycubic Linear Kossel / Kossel Plus (whatever branding they’re using when you look) 3D printers for the last couple months, including one I bought personally. While I’m overall extremely pleased with them, there are a whole bunch of notes, fixes, and improvements I feel like should be collected somewhere.

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An Experiment in Water Cooled 3D Printing Extrusion

Scrapheap Challenge: The world’s worst syringe pump.

Or, three hours enjoyably lost to a visit from the bad idea fairy.

My PhD advisor and I were chatting in the lab today and had an idea that it would be interesting to try to drip/jet a bit of water onto just-extruded filament, ideally in small enough quantity that it phase changed and flashed off with all the excess energy, in order to allow printing unreasonable unsupported structures.

It unfortunately doesn’t look like it will be practical, but we got a PoC-grade implementation in a few hours and it seemed worth a quick write-up to document our experiment for the interwebz.

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Aneng AN8009 DMM with Hacks

Aneng AN8009 DMM

I just picked up an Aneng AN8009 DMM as an upgrade to the cheap, cheap (but surprisingly OK) Circuit Specialists branded MY-68 I’ve had as my home on-desk approxometer for ages. It’s a nice meter for $30ish, and can be readily hacked to improve its performance. I tend to point people to mid-range Uni-T DMMs when they asked for decent hobby meters, but now I might switch to one of these plus one of those little $10 Atmega328 based component testers cloned everywhere for ~$10 as basic electronics lab instruments.

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A Bit of 3D Printer Maintenance

We were doing a bit of beginning-of-summer lab maintenance and one of the projects was to figure out why the MakerGear M2 (Which has been heavily modified over the years, Azteeg x5 mini motherboard, E3D hotend, etc.) was behaving so strangely.
Well… there’s your problem.
Fresh 0.35mm nozzle next to the bored out, abraded down corpse of a nozzle that we’ve, in retrospect, been running for something like 3 years. Turns out printers work much better when the nozzle aperture is roughly the size it’s supposed to be.
Still seeing some odd temperature fluctuation, but … look at that thing.

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Ruideng Adjustable Bench Power Supply

I built myself a little adjustable bench power supply from Chinese modules, partly because I thought it would be handy to have one, and mostly because I wanted a small, straightforward project to do for my own sanity.

I set up a slightly different configuration than is typical, and am documenting it for funsies and/or to ease clones if anyone is so inclined. The whole project was about $60 all-in, for an (approximately) 0-34V, 0-5A adjustable bench power supply.
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MicroChorder

I hacked together an Arduino Micro firmware that is a drop-in replacement for a Spiffchorder, long version and code below the fold.
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Ebay DB25 Arduino Nano grbl Adapters

A second consecutive CNC post, because I haven’t had time to write up long-form posts for months, and something requiring documentation came up today.

While I’m still quite happy with LinuxCNC (especially since I discovered NativeCAM), my adviser bought himself a GRBL-DB25 adapter board for his 3040T mentioned in my previous post. He has been unsurprisingly unsatisfied with the performance of the terrible old SFF P4 box he has been using to drive it with LinuxCNC, and we’ve (read: I’ve) become reasonably comfortable with grbl due to the several shitty diode laser cutters that have recently proliferated around here (One or more of the involved parties will be posting about those shortly). As I’ve noted elsewhere, grbl is not my first choice, but has reached baseline required functionality in versions >1.1 and is unarguably convenient.

In particular, he went with one of the Arduino Nano based boards floating around ebay with titles like USB 3-Axis CNC TB6560 Driver Board Controller Converter GRBL Arduino Nano DB25, which are unfortunately both undocumented and (as it turns out) unsuitable. He asked me to help set it up, and this post serves to document and warn based on my findings.

It seems like it should be a great solution, but it will not work with the typical black control boxes that come with many little aluminum CNC machines or most other common 3 or 4 axis breakout boards. It has the (dead) URL www.getlofi.com/grbl-to-3axis on the silkscreen, and while getlofi.com does appear to be a valid page run by some hackers mostly into circuit bending, I couldn’t shake any mention, much less relevant documentation out of the page. What I did find with a continuity tester and some patience is the following unfortunate arrangement:

The problem is that the designer decided to tie DB25 pins 2,6,and 14 together to nano pin 11 (D8) with traces on the adapter. This renders it completely unusable with the 2-7 StepX/DirX/StepY/DirY/StepZ/DirZ pinout the vast majority of boards use, as StepX and StepZ are wired together. If I’m inferring which shitty blue TB6560 3-axis board it’s designed to work with correctly, 2, 6, and 14 are intended to be per-axis stepper enable pins, but that is not a particularly common configuration.

For contrast, I picked up one of the Arduino GRBL to DB25 CNC Shield Kits available from “Ron” on Tindie to throw in my parts bin for testing. It’s actually documented, supports the pin-out most parallel control boards I’ve encountered use (with the default grbl pinout no less), and has each individual pin broken out like a sane designer, so it should support any reasonable configuration. I tried my tindie board with the machine that was supposed to get the fail board, and it seems to work fine, so I’m going to encourage picking up one of those instead (unless we get ambitious and just cut our own DB25-Nano board).

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3040Z CNC Router

Complete 3040Z CNC System

I’ve been fascinated with machine tools and mechatronics for well over a decade, and have been indulging that fascination with a series of little benchtop CNC machines since about 2008, especially since my collection of related degrees lend legitimacy to my desires. Because of my other lifestyle choices I’m more or less restricted to a machine which is small and well-behaved enough to operate in an apartment, is roughly man-portable, and fits in normal vehicles, at least for the time being. Possibly fortunately, this restricts me from going off the deep end and buying a small VMC, or even building out the heavier classes of benchtop machine.

Last year I started to feel like my old V1 Shapeoko (ca. 2012) was not really usable as a machine tool – it was a good toy, and I learned a ton of cool things from it, but it wasn’t stiff enough, reliable enough, or laid out in a way that made it practical to use for much of anything. After I had my Shapeoko on campus for a demo day, my adviser was inspired to buy himself a complete package Chinese 3040 CNC router, and I got a chance to play with that for a few days. I wasn’t terribly impressed with the electronics on it, but the frame proper impressed me enough that I decided I wanted one as an upgrade.

…So near the end of the spring semester, I ordered myself a bare 3040Z frame and a pile of parts to kit it out. The machine is built almost entirely from inexpensive Chinese components, purchased via a mixture of Aliexpress, eBay, and Amazon sellers (I’ve become fond of uxcell for small parts). I don’t have accurate or current price quotes for the whole thing because I bought as I went, and various parts are reused from previous projects. I suspect the total is in the neighborhood of $1200 – comparable to buying a slightly more powerful finished system without the enclosure or limit switches.

It was my intention to write this up in sections as I built it out, but kept opting to play with work on the machine instead of doing more writing – particularly since such a large part of the things I’m supposed to be doing with my time of late are also writing. I finally got the last of the major parts “done” to my satisfaction a few weeks ago, so it’s time to gather the pictures and notes from what should have been half a dozen topic posts and make a gigantic brain-dump.

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