# cnlohr/channel3

ESP8266 Analog Broadcast Television Interface

Repository: https://github.com/cnlohr/channel3
Canonical: https://ross.abutalabs.com/products/channel3
Language: C
License: NOASSERTION
License Family: other
Last push: 2025-11-01T00:06:15+00:00

## Health v2 (maintenance only)
Score: 54/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 49, release rhythm 35, longevity 100
- inputs: {"age_days": 3868, "days_push": 306, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases, no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1573, forks 167 (observed 2026-08-28T04:05:05.661732+00:00)

## What it is
Firmware for the ESP8266 that turns the chip into an analog broadcast television transmitter, outputting an NTSC/PAL-compatible signal on Channel 3 from GPIO3. It exploits the I2S bus at an 80 MHz bitclock with DMA buffers to modulate luma and chroma signals that a vintage analog TV can tune into with an antenna.

## Use cases
- display video output from an esp8266 on an old analog tv
- generate ntsc or pal television signals from cheap hardware
- experiment with rf signal generation on the esp8266
- build a retro tv demo without extra video hardware
- learn how analog tv luma and chroma modulation works
- hook an antenna to gpio3 and broadcast on channel 3

## When to choose
- you have an ESP8266 and an analog TV and want video output with no additional hardware
- you want a hands-on project for learning RF modulation, DMA, and the I2S peripheral
- you are building retro hardware demos that display on vintage CRT televisions

## When to avoid
- you need a legal, compliant video transmitter - unlicensed RF broadcast may violate regulations in your jurisdiction
- you need modern digital TV output (HDMI, DVB, ATSC) rather than analog NTSC/PAL
- you need high image quality - the signal is intentionally hacky with artifacts like dot crawl

## Facets
- artifact type: application
- maturity: active
- function: embedded, graphics
- domain: embedded-systems, hardware, media
- platform: embedded, iot
- tags: esp8266, analog-tv, ntsc, pal, rf-signal-generation, i2s, dma, firmware, channel3, hack

## Member repositories
- cnlohr/channel3 (main) score 54

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:05.661732+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T03:58:02.769599+00:00, confidence not recorded.
  - readme: https://github.com/cnlohr/channel3 (fetched 2026-08-28T04:05:05.661732+00:00, sha e3de6665339d)
- Data as of 2026-08-30T08:39:29.467469+00:00.