rnd:sketchpad

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rnd:sketchpad [2023-12-15 04:19] – [CAN/OBD sniffer] asdfrnd:sketchpad [2024-10-01 05:10] (current) – asdf
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 ====== Sketchpad ====== ====== Sketchpad ======
-A home for project ideas that aren't yet fully formed (and which may never be). Those that do survive this gestation phase should receive their own pages, and rejects should probably be retained somewhere. +A home for project ideas that aren't yet fully formed (and which may never be). Those that do survive this gestation phase should receive their own pages, and rejects should probably be retained somewhere. 
 + 
 +===== Teensy softcard for Apple II ===== 
 +Build an Apple II softcard based around the Teensy microcontroller. I'm not yet sure what we'll do with it yet, but we should try to keep as many special pins (the main I2C/SPI buses, maybe a UART bus) free for later use. Maybe one corner of the initial card could be a protoboard, or we could have some of the free pins broken out for jumpers to a breadboard. Sample projects for inspiration: 
 + 
 +  * https://github.com/rallepalaveev/A2DVI/blob/main/v2.0/A2DVI.v2.0.sch.pdf 
 +  * https://www.tindie.com/products/cvt/esp32-softcard-expansion-card-for-the-apple-ii/ 
 +  * https://www.v2retrocomputing.com/analog (can be used as a VGA output //or// a Z80 softcard!) 
 +  * schematics and details in the MS SoftCard manual 
 + 
 +We don't yet have a specific use case in mind. Some ideas: 
 + 
 +  * I2C/SPI/UART interface 
 +  * some kind of audio card/MIDI thing? 
 +  * ProDOS disk emulation (via SD card) 
 +  * Z80 softcard 
 +  * ethernet? 
 +  * USB bus sniffer 
 + 
 +It may make sense to start with a very simple breakout card and a basic bus sniffer firmware.  
 + 
 +===== Dual Euclidean trigger/gate module with logic ===== 
 +Generate two independent channels (A and B) of Euclidean gate sequences and a third channel (A * B) which performs a selectable logic function on A and B. Attach LEDs to the output of each channel for visual indication. CV control over the parameters would be welcome but is not necessary for the first version.  
 + 
 +Note that this will need to able to follow an external clock! 
 + 
 +===== Bluebox MIDI sync ===== 
 +The [[:sounds:Bluebox]] is a wonderful piece of gear, but synchronization can be a pain. The core problem is that it has no option to disregard STOP messages((At least as of firmware 1.2.21.)). All those delicious tails have to go to waste! We need a middleman device to filter out STOP messages headed into the Bluebox. All other gear should be placed upstream from said device.  
 + 
 +We have already unsuccessfully trialed the [[:sounds:Zoia]] for this purpose. There is no way to fully isolate the transport messages.  
 + 
 +The attached Python script will work in a pinch, but a more robust solution is desirable. Something Daisy-based?  
 + 
 +<file python midifilter.py> 
 +#!/usr/bin/env python3 
 + 
 +'''JACK client for filtering out stop (0xfc) messages''' 
 + 
 +import jack 
 + 
 +client = jack.Client('MIDI filter') 
 +inport = client.midi_inports.register('input') 
 +outport = client.midi_outports.register('output') 
 + 
 +stop = bytes.fromhex('fc') 
 + 
 +@client.set_process_callback 
 +def process(frames): 
 +    outport.clear_buffer() 
 +    for offset, data in inport.incoming_midi_events(): 
 +        if data == stop: 
 +            continue 
 +        outport.write_midi_event(offset, data) 
 + 
 + 
 +with client: 
 +    print('#' * 80) 
 +    print('press Return to quit') 
 +    print('#' * 80) 
 +    input() 
 +</file> 
 + 
 +The [[https://conductivelabs.com/mrcc/|Conductive Labs MRCC]] is fully capable of MIDI message filtering, and it can do so selectively --- in other words, I could feed the clock and transport from Pam's to all devices at once but block the STOP messages only to the Bluebox.  
 + 
 +===== MIDI "mixer" ===== 
 +Selectively mute and mix different components of a MIDI stream.  
 + 
 +**This already exists!** It's called the [[:sounds:MRCC]], and I have one.  
 +===== 8800 Lisp interpreter ===== 
 +Why not? I like the Altair, and I like Lisp. Some starting points: 
 + 
 +  * [[https://web.archive.org/web/20240116154313/https://blog.nullspace.io/apple-2-lisp-part-1.html|Apple 2 Lisp, part 1]] (part 2 was never written) 
 +  * [[https://github.com/hausdorff/turtles|source for the above]] 
 +  * [[https://github.com/ghosthamlet/awesome-lisp-machine]]
  
 ===== Convert PC PSU to Eurorack ===== ===== Convert PC PSU to Eurorack =====
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 ===== Microcontroller-based LLDP sniffer ===== ===== Microcontroller-based LLDP sniffer =====
 +//See [[.:projects:tnt]]//
 +
 This would be a great combination with [[.:projects:aft]]. I've discovered that most switches at work source LLDP packets, which can be helpful to identify where a given cable ends up. Having a device that could capture these packets and decode fields of interest would be extremely handy. This would be a great combination with [[.:projects:aft]]. I've discovered that most switches at work source LLDP packets, which can be helpful to identify where a given cable ends up. Having a device that could capture these packets and decode fields of interest would be extremely handy.
  
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 ===== GreatFET as keyboard ===== ===== GreatFET as keyboard =====
 +//See [[.:projects:gfkb]]//
 +
 Use the [[:GreatFET]] to accept keypresses (and maybe mouse input somehow) from one machine and pass them on to another as a USB HID. To capture special keys like ''C-M-del'' and the like, maybe open [[:ncurses]] in raw mode as the input window.  Use the [[:GreatFET]] to accept keypresses (and maybe mouse input somehow) from one machine and pass them on to another as a USB HID. To capture special keys like ''C-M-del'' and the like, maybe open [[:ncurses]] in raw mode as the input window. 
  
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 } }
 </graphviz> </graphviz>
 +
 +Also take a look at the [[https://www.hfsignals.com/index.php/ubitx-v6/|uBITX]] and [[https://www.vu2ese.com/index.php/2022/07/20/the-sbitx-the-sdr-for-the-homebrewer/|sBITX]]. These are homebrew multi-band superheterodyne transceivers built around an Arduino/Teensy and a Raspberry Pi, respectively. Each project includes detailed schematics, block-by-block circuit descriptions, and firmware/UI explanations. Both also use the Si5351 clock generator to produce the local oscillator(s). 
 ===== Email pingback ===== ===== Email pingback =====
 Sometimes it's handy to know when someone opens an email.  Sometimes it's handy to know when someone opens an email. 
  • rnd/sketchpad.1702613946.txt.gz
  • Last modified: 2023-12-15 04:19
  • by asdf