Soda stream replacement
In one of your podcasts, you discussed how to make a system that does what soda stream does at a fraction of the cost. I am wondering if you could put your specifications for that on the site.
You can buy individual components from Micromatic.com for a bit less, but this kit will serve the purpose. A single, inexpensive fill of the CO2 tank at a welding supply store will last for years: https://www.kegoutlet.com/sp202-taprite-soda-carbonating-kit-taprite-regulator-5-lb-co2-tank.html