That might be able to be added without too much difficulty. In the 80's there used to be an add on kit that fit most cars.

One could be generated with a time delay relay, generally all you need to do is get the wiper motor past the park position and it will make a full sweep on it's own. Does your car have a manual "mist" ( one wipe ) function?

Someone is bound to still make a retro fit. Try electronic kit makers like Spark Fun , Velleman.

If that fails, 80's Fords used a control box between the wiper switch and harness that might be able to be adapted to your needs. Retro fitting Fords was easy, change the wiper switch and plug the control box and you are done.