The MGA is equipped with a Lucas DR2 wiper motor, as did some other British cars from the 1950s and 1960s, such as the Triumph TR2 and probably others. It's a single speed motor.

The wiper system is well described here, but here is the schematic of the factory configuration :

Wiper motor wiring schematic from MGAGuru

Notice the 3 terminals on the motor (1,  2 and E). Continuous +12V comes to terminal 2, then grounding the motor via the dash "W" screenwiper switch (on terminal 1) starts the motion of the motor, then the grounding is taken over via terminal E regardless of the position of the wiper switch until the wiper blades are back in their parked position. Then if the switch is still closed, the wiping continues, otherwise it stops until the switch is closed again by the driver.

When driving through light rain at moderate/slow speed, I find the continuous wiping motion to be too much, and I end up manually switching ON then OFF the wipers to get one wipe, then wait a few seconds, and switch ON then OFF the wipers again to get another wipe... etc.. In other words, I was manually making the wipers intermittent.

This project is about making a controller that simulates what I was manually doing, by switching ON-OFF the wipers at a given (and variable) frequency.