As any Vectrex fan knows, the joystick controller is analogue rather than digital. This means pushing the joystick lever in a particular direction gives a voltage signal range rather and an on/off signal. The potentiometers in a Vectrex joystick work by voltage division and pushing the joystick lever from maximum up to maximum down gives a voltage in the range of 3.4V to -3.4V with 0V representing the lever in the centre position. A similar situation exists when pushing the lever from left to right. An analogue joystick can give finer control. Interestingly, there are not many Vectrex games that make use of the analogue functionality. Instead software in most Vectrex games simply processes the analogue signal as a digital value i.e. all-or-nothing joystick response.
I’ve been searching several months for a large analogue joystick. Occasionally you see real analogue joysticks ripped out from old arcade machines but the pricing is very expensive (>£100!). You can also purchase brand new analogue joysticks for arcade machines (see the Happ Analog joystick at Gremlin Solutions ). Likewise you can find analogue joysticks used for controlling industrial machinery. However, all of these options are even more expensive and would require some extra circuitry so that the voltages generated are within the Vectrex signal range.
Recently, I purchased some old home computer analogue joysticks for less than £5. I bought them to see if any of them could be modified and easily mounted in my future control panel for the VecCab. However, although electrically they could be modified to work with the Vectrex, it’s not going to be easy to mount them behind a control panel.
I haven’t given up on modifying one of these joysticks but for the moment I've decided to pursue making a control panel using a digital joystick. There are already circuits presented on the internet which show how to interface a Vectrex to a digital joystick. The only disadvantage of using a digital joystick is that some Vectrex games will not be playable. However, as these games are very few in number (Hyperchase comes to mind) the disadvantage is not that much of an issue. But one day I would like my VecCab to be 100% with all Vectrex games.