Add Proportional Speed Control to Your On/Off RC Model
RC models like race cars and boats can be had very cheaply. Because of their low price they only feature binary controls like Left/Right and Go/Stop. However, an enthusiastic engineer can easily transform these controls into proportional ones if there is enough free space inside the model. Of course, it takes some fiddling and hacking to get it right, but that is exactly what you like about this hobby.