This was my submission to a design competition for a home coffee roaster on GE's open innovation platform, FirstBuild. While most products on the market are larger and expensive ($300-$1000), this approach is cost-accessible, using the oven as the heat source and source of coffee bean agitation.
Coffee beans require heat and movement in order to activate the oils and remove the papery shell. Most modern ovens have a convective fan within their chamber, so directing the flow of hot air as a popcorn popper upward in a chamber past the beans, they both roast and de-chaff. The chaff is collected in a small cup and any smoke is collected by a carbon filter.
Once the beans have roasted as desired, they need to be quickly brought to room temperature. There is a separate salad spinner-type device that rapidly air cools the beans using the roasting chamber. It efficiently moves the air like a rotating ventilation cap while centrifugally driving the beans up a wall for maximum convective cooling.