In comparison to our other senses, there has been relatively little work on how our sense of smell can be effectively utilised in a Human-Computer Interface. We argue that the lack of easy access to 'off-the-shelf' computer controlled scent delivery devices restricts research in this area, and that without understanding what smell can be used for, there is little commercial case to make such devices available. In considering these issues, we have developed Hajukone: a smell delivery device that is both open source and can be built with low technical skills, yet provides high quality olfactory capabilities. We outline the design of Hajukone, showing how it overcomes critical design requirements that have restricted prior research, before outlining our future plans for its development and use.