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Lean2
Personal blog · iosoft.bloghardwareprogramming
Lean2 is a personal blog at iosoft.blog about hardware and programming. Since 2018, 7 different Hacker News readers have linked it 8 times, most often “Raspberry Pi 16-channel WS2812 NeoPixel LED driver”. It is still writing: the last post was on 2026-06-29, and you can follow it by feed.
My 'TCP/IP Lean' books are out of print, but I'm still using the same philosophy when designing embedded systems: trying to understand the fundamentals, so as to avoid the bloat that results from a simplistic building-block approach to hardware & software. So I'm posting some projects taken from my
Most-linked posts?
- Raspberry Pi 16-channel WS2812 NeoPixel LED driver2 people · 3 mentions · first linked 2020-10-13
- Raspberry Pi Secondary Memory Interface (SMI)2 people · 2 mentions · first linked 2020-09-01
- Real Time Location Using Ultra-Wideband (UWB) (2019)2 people · 2 mentions · first linked 2021-11-11
What Hacker News says?
> The ADS7953 is somewhat of a ferrari, whereas the MCP3208 feels like a Toyota, simple to use, unimpressive performance. What about the AD9226? It only has a single channel but can do up to 65 MSa/s at 12 bits. I bought one as a module for around $12 on AliExpress to experiment with software decoding of analog video. I only run it at 20 MSa/s and only use 8 bits because, funnily enough, the limiting factor is the s…
Comment linking /2020/07/16/raspberry-pi-smi/
on “How bad can a $2.97 ADC be?”Submitted Raspberry Pi Secondary Memory Interface (SMI) as a story · 38 points
HN discussionI'd recommend setting them up in parallel and using this fantastic driver: https://iosoft.blog/2020/09/29/raspberry-pi-multi-channel-ws... . Anecdotally I was able to drive 16 200 pixel strings at ~180Hz with a Raspi 4B. Running in series with the regular adafruit library would work as well but at this number of pixels the refresh rate might start to get a bit choppy, and you probably want to add power in the middle…
Comment linking /2020/09/29/raspberry-pi-multi-channel-ws2812/
on “48x32: A 1536 LED Game Computer”Submitted Show HN: Programming FTDI devices in Python as a story · 22 points
HN discussionThe tricky thing with bit-banging neopixels is that the entire string has to be sent in sequence and the timing is quite tight. With the standard (modern) libraries you need the entire string ready to go in memory, which would've made things tricky with 90s RAM capacities. Semi-related: non-real time systems like the Raspberry Pi usually need to make use of audio/PWM hardware for neopixels and thus can only control…
Comment linking /2020/09/29/raspberry-pi-multi-channel-ws2812/
on “48x32: A 1536 LED Game Computer”Submitted Real Time Location Using Ultra-Wideband (UWB) (2019) as a story · 12 points
HN discussionSubmitted Raspberry Pi 16-channel WS2812 NeoPixel LED driver as a story · 2 points
HN discussionSubmitted Real Time Location Using Ultra-Wideband (UWB) as a story · 1 points
HN discussion