ofxPiMapper is projection mapping software that runs on the Raspberry Pi mini-computer. It comes as an addon for the openFrameworks creative coding toolkit, is open source and available on GitHub.
It is free and open source, but the code is still written by humans, it takes time. Web servers and other related services are not for free, computers fail and have to be repaired. Sometimes it is nice to be able to afford to grab a beer. Please consider sharing your wealth if you find this project useful. There are options below.
Consider donating, especially if you are a design, advertisement or any other agency or company that is using this to reduce costs, pump up profit, PR activities, etc.