[HN Gopher] Chiptunes on an ATtiny4 and the 3 Cent Micro
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       Chiptunes on an ATtiny4 and the 3 Cent Micro
        
       Author : electricant
       Score  : 176 points
       Date   : 2021-05-04 12:24 UTC (10 hours ago)
        
 (HTM) web link (gir.st)
 (TXT) w3m dump (gir.st)
        
       | victorthehuman wrote:
       | Nice! It reminded me of this great little synth powered
       | parasitically from the MIDI port.
       | 
       | https://mitxela.com/projects/flash_synth
        
       | z5h wrote:
       | Amazing work. Bravo.
       | 
       | If anyone is interested in an incredible piece of music along
       | these lines, please do yourself a favour and check out
       | 
       | TRISTAN PERICH 1-BIT SYMPHONY
       | 
       | http://1bitsymphony.com
       | 
       | (you can skip buying the hardware and find the music on Spotify
       | and similar)
        
         | zibzab wrote:
         | What mcu does this use?
        
         | ionwake wrote:
         | This is amazing - thanks for the link
         | 
         | EDIT > Are there any similar products to this which are
         | procedurally generated? Is the OP procedurally generated?
        
           | flobosg wrote:
           | 1-Bit Symphony is not procedural.
           | 
           | Also, not quite procedural either, but the Buddha Machine
           | might be worth having a look:
           | https://en.wikipedia.org/wiki/FM3#Buddha_Machine
        
         | StavrosK wrote:
         | https://www.youtube.com/watch?v=apDFVsBDCYE
        
           | qwertox wrote:
           | LOUDNESS WARNING! Sounds like a square wave at volume level
           | 11.
           | 
           | A downvote for this? It nearly blasted my ears while
           | listening this on in-ear headphones after listening to
           | "Chiptunes on the ATtiny4".
        
             | StavrosK wrote:
             | Oops, yeah, it is quite loud.
        
       | tomcam wrote:
       | Inspired and, unlike so many of my embedded projects, completed.
       | Respect. Also a great writeup with video.
        
       | throwaway316943 wrote:
       | Something I've wanted to do for a while but I lack time and SMD
       | skills for is to build a neural net from individual ICs like
       | this.
        
         | dragontamer wrote:
         | SMD is less tedious when you know what you're doing.
         | 
         | Though hole has... well... holes. It requires tediously placing
         | all your stuff through those holes.
         | 
         | SMD on the other hand, can be solder-pasted and then baked with
         | a $20 skillet + hot air gun to finish off the last bits. The
         | solder has surface tension and naturally "pulls" pieces into
         | place.
         | 
         | SMD is slightly more expensive than a soldering iron: you still
         | need the soldering iron for some bits. And solder paste goes
         | bad over time, and flux to keep stuff clean. You'll also need
         | more expensive PCBs with a solder mask if you want to keep
         | things easiest (but its really not that much more expensive:
         | most costs seem to be shipping costs these days).
         | 
         | So you get your skillet (or toaster oven), a hot air gun,
         | soldering iron, solder wire, solder paste, and finally flux...
         | and you're pretty much set.
         | 
         | Maybe get some "desoldering" pump and "desoldering braid", in
         | case you need to rework some stuff. But the skillet + hot air
         | gun works pretty well.
         | 
         | -------------
         | 
         | Work with larger 0805 resistors/capacitors. They look small at
         | first, but you can probably work at that level even without
         | tweezers. More skilled people can work with 0402 and smaller
         | pieces (though that's entering tweezer-only territory)
         | 
         | If 0805 is too small, there are larger pieces available like
         | 1206. But I personally think 0805 sufficiently large for
         | beginners to work with.
         | 
         | EDIT: I'm talking about American codes. 0805 American is
         | equivalent to 2012 European.
        
           | Teknoman117 wrote:
           | I just ordered some boards where I used a lot of 0603 (1608
           | metric) passives, first time doing something quite this
           | small. I did use the "hand solder" version of the footprints
           | in KiCad. Tiniest things I've done by hand are some TSOT-23-6
           | packages and a 386EX33 in that annoying PQFP-132 package (the
           | millipede).
           | 
           | Want to try using a flat tip I use for QFPs, but if it's too
           | difficult, I'll get some solder paste and use my hot air
           | station (which I initially bought to de-solder some seriously
           | annoying DIPs (DS1687+ in EDIP) on some old SBCs - the solder
           | just would not come out with solder wick or a pump).
           | 
           | I'm basically imagining tweezers and holding one's breath.
        
         | helsinkiandrew wrote:
         | The through hole versions of the ATtiny chips are still
         | available - 58 cents in single quantities from digikey,
         | probably cheaper elsewhere
         | 
         | https://www.digikey.com/en/products/filter/integrated-circui...
        
         | thequux wrote:
         | SMD soldering is not actually that hard until you start getting
         | to the really small stuff; you just need some extra tools and a
         | decent amount of practice. The smallest packages you're not
         | likely to have a choice about are QFPs, which have 0.5mm pin
         | spacing. In order to solder these, you need: * ESD tweezers
         | (available for a couple bucks on Aliexpress, you want a set
         | that contains at least a pair of fine straight tips and a pair
         | of hooked tips) * A decent temperature-controlled iron. I
         | generally use a Pinecil, but a TS-100 is also quite nice. I
         | generally use the D24 tip; for all but the most detailed work,
         | the super-fine conical tips are more trouble than they're
         | worth. * 63/37 SnPb rosin core solder, preferably 0.3mm
         | diameter or smaller. I use ChipQuik RASW.031, but it doesn't
         | matter that much. This should cost somewhere around EUR10 * A
         | self-standing magnifier. The microscope I use cost EUR300 on
         | eBay, but a third hand is available for under EUR10. You
         | probably don't need any more than 10x magnification. * Copper
         | braid. A small spool (it goes a long way) should be around
         | EUR10-20 * (Optional) A bottle of strong beer or a glass of
         | wine. If in Eastern Europe, palinca or vodka is an acceptable
         | substute
         | 
         | With this stuff at hand, if you're going the beer route, drink
         | it. It'll have two effects: your hands will shake less, and
         | you'll care less how it looks.
         | 
         | Now, tape your board down and set up your magnifier so that you
         | can comfortably look through it as you work. Pick a pad on the
         | footprint of the biggest thing that needs to be soldered
         | (preferably on the side that you hold your iron with). Apply
         | enough solder that there's a noticable bulge. Now, pick up the
         | chip with the tweezers in your non-dominant hand, place it in
         | the right place. While holding the chip in place with the
         | tweezers, melt the solder you placed earlier using your iron
         | until it wicks onto the pin of the chip. Check the opposite
         | corner and make sure that it's lined up, then put a small blob
         | of solder there. Don't worry if you bridge some pins; it's easy
         | enough to fix. Now, solder the rest of the pins. If you're
         | feeling dexterous, you can solder each pin individually, but I
         | don't usually bother. Alternatively (and this is what I usually
         | do), just solder all the pins down with a blob every couple of
         | pins. Most of them won't end up bridged because soldermask
         | repels solder. Once every pin is soldered down, press the wick
         | against the joint with the iron to suck up all the excess
         | solder. Inspect all the joints to make sure you've gotten all
         | the bridges. If there are still some, there are a number of
         | different techniques to get rid of them, but usually just
         | sliding the tip of your iron along the space between the pins
         | will be enough. Worst case, put more solder on and rewick it.
         | Congratulations, you're done!
         | 
         | Repeat for each chip, until you're good at it :-D
         | 
         | (FWIW, I learned from this guide
         | http://goodfet.sourceforge.net/construction/ , which goes into
         | more detail, and also has a nice technique involving taping
         | chips down that works very well)
        
         | Y_Y wrote:
         | Maybe you should try one of those GreenArrays GA144 boards.
         | They give you a 12x12 square grid of crappy forth CPUs,
         | connected at grid edges.
        
       | [deleted]
        
         | [deleted]
        
       | djmips wrote:
       | Could sound better with a filter on the output.
        
         | kennywinker wrote:
         | It has one, check out the section labelled "Output filtering"
        
         | exDM69 wrote:
         | Yes, the legendary SID chip was a digital oscillator followed
         | by an analog filter.
         | 
         | After seeing this heroic SID chip reverse engineering (0), I
         | tried building the filter section using a quad opamp to make
         | the state variable filter. It sounds kinda nice for such a
         | simple circuit.
         | 
         | I've been planning a project of using a micro controller to do
         | the oscillators and then use the PWM outputs to drive the
         | filter control voltages.
         | 
         | (0) http://forum.6502.org/viewtopic.php?f=8&t=4150
        
       | girst wrote:
       | Hi, author here. What a nice surprise to see my project turn up
       | here :)
       | 
       | If you have any questions, shoot!
        
       | gsliepen wrote:
       | A similar project, created by a ex-colleague of mine, with an
       | ATtiny85, that also broadcasts the generated sound via FM:
       | https://www.youtube.com/watch?v=7t7_naYJnHo
       | 
       | Here is the code running on the chip:
       | https://github.com/spookysys/attiny-synth
        
         | ionwake wrote:
         | Is the Revolt! still on sale? I couldnt find any links for
         | something similar - does he not have an etsy?
        
       | Teknoman117 wrote:
       | I'm frankly amazed at how cheap getting PCBs made is these days.
       | When I first started out my electronics hobby in the 00's,
       | everything I did that I wanted to be "permanent" was done on
       | perfboard with through the hole parts, ordering PCBs was a pipe
       | dream for a teenager funded mostly by birthday and Christmas
       | gifts, even if the ads in Servo magazine suggested otherwise.
       | 
       | I took nearly a decade off (shifting into contract app/game dev
       | work, university, and then starting my career did not leave a lot
       | of room for my electronics/robotics hobby) and now the bargain
       | basement price for a batch of 5 "passable" quality boards is <=
       | $10 (and "good" quality for <= $50), surface mount parts suddenly
       | became very accessible and to be honest, for some of the stuff
       | I've played around with, the price savings by using SMT usually
       | pays for the boards. DIPs are getting really expensive. It
       | completely blows my mind.
        
       | qwertox wrote:
       | So this was trial-and-error on the hardware directly, without
       | simulating it first in software?
       | 
       | I can't imagine how tedious this must have been. It's fascinating
       | what can be archived with determination and this little piece of
       | hardware.
        
         | girst wrote:
         | First, the music itself wasn't written by me, but by Rob
         | Miles[1]. So I had a version in C available. I then iteratively
         | transformed the code into simpler and simpler expressions, and
         | finally into a simulated assembly language, written as C
         | macros[2]. Only the final step, initializing peripherals,
         | stetting up interrupt handlers, etc was done with the actual
         | chips. Of course, I made some erros with the before mentioned C
         | macros, so some final debugging was trial-and-error. Later on I
         | also used simulators, but they don't support all the necessary
         | features of the MCUs, or were outright broken[3] (patches now
         | upstream).
         | 
         | [1]: http://txti.es/bitshiftvariationsincminor
         | 
         | [2]: https://git.gir.st/Chiptunes-
         | pms150c.git/blob/f1b013452400b0...
         | 
         | [3]: https://sourceforge.net/p/sdcc/patches/379/
        
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       (page generated 2021-05-04 23:01 UTC)