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InfluxDB
Power Real-Time Data Analytics at Scale. Get real-time insights from all types of time series data with InfluxDB. Ingest, query, and analyze billions of data points in real-time with unbounded cardinality.
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PiClosedCaptions
A system for sending a closed captions signal over the raspberry pi's composite video signal
This project does exactly what you are describing by messing with the registers in the BCM chip I believe: https://github.com/ali1234/raspi-teletext
It can also be done with an arduino setup, see: https://github.com/ali1234/avr-teletext
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