This one was inspired by Driving a flyback with pure AC sine wave but I wasn’t sure if my answer was a good fit to te question, so I reproduced it here.
This article was inspired by my question on Retrocomputing, on Stack Exchange, Largest memory peripheral for Sinclair ZX81? and turned into a list of links to vintage computing magazines.
Trash80 recommends using a 6N138 in the ArduinoBoy, see the schematic. I had subsequently order a batch of 6N138, in order to build an ArduinoBoy, see Making your own ArduinoBoy. Then I started looking at the use of optocouples for other MIDI applications. However, many other users recommend 6N137 for MIDI applications, and I ended up getting the two confused.
So, how different are they? Are they interchangable? Is the 6N138 the right optocopuler for the ArduinoBoy?
Many moons ago, before I knew anything about Arduino, I bought a “minimum ATmega kit” from eBay, pretty much like this, DIY ATMEGA8 Minimum System Board ATmega48 ATMEGA88 Minimum System Board AVR Kit. It arrived, I built it, I put in in a box and forgot all about it until today, when I came across it.
But once you’ve made it how can you use it and what are the buttons for?
There are an awful lot of cheap MK8 extruders, and their derivatives (close and not so close), out there – with different number of parts, different bolts (lengths and thicknesses), screws, washers, varying arm designs (enclosed or non-enclosed bearings), etc.. However, not many assembly instructions. So I’ll ramasser a few different assembly pictures here.
This post was inspired by How to build the extruder motor holder for the Kossel Mini
Following on from USB to MIDI connections, I had a few quarms about the 6N137. The information below is taken from the now deleted question, 8 pin high speed opto-coupler replacement for 6N137 [closed]
This question, How were the first ZX Spectrum games written?, got me thinking about how I used to code the ZXSpectrum, which was using assembler, via a BASIC program (not app) called EZ-code, which came from the excellent book by William Tang, Spectrum Machine Language For The Absolute Beginner. Then I found this question Where can I get the errata sheet for Spectrum Machine Language for the Absolute Beginner?