Ventilation fans are useful for clearing stuffy or stale air out of a space. However, they also tend to act as a gaping hole into said space. In the case of caravans and RVs, an open ventilation fan can be terrible for keeping the interior  space warm, quiet, and free from dust. “Blast doors” or fan blocks are a common way to solve this problem. [Raphtronic] whipped up a duly-equipped ventilation fan to do just that.

The solution was to create a fan setup with a custom fan holder and a sliding door to block airflow when necessary. [Raphtronic] designed a fan frame for this purpose using parts 3D printed in ASA plastic. This material was chosen such that they could readily withstand the 50 C (120 F) temperatures typical in his Ford Transit camper during the summer. A simple 12 V ventilation fan was then fitted to the frame, along with a sliding door controlled by a 12 V linear actuator.

The mode of operation is simple. A DPDT switch controls the linear actuator. Flipped one way, the linear actuator is fed 12 V in such a polarity as to move it to open the fan door. In this mode, 12 volts is also supplied to the fan to start ventilation. When the switch is flipped the other way, the actuator moves to the closed position, and a diode in the circuit stops the fan spinning backwards. As a bonus, limit switches are built into the linear actuator, so there’s no need for any microcontrollers, “off” switch positions, or additional wiring.

It’s a tidy solution to the problem of ventilating a camper in a clean and effective manner. Files are on GitHub for those wishing to build their own. We’ve seen some great work in this area before, like this off-grid van project that made excellent use of 3D scanning during the build process. If you’ve designed and built your own nifty camping gear, don’t hesitate to drop us a line!