How Does a Swimming Touchpad Work? Here's the Explanation

How Does a Swimming Touchpad Work
Touchpads are extensively used in swimming competitions due to their accuracy and reliability. But how do these swimming touchpads work? This Buzzle post explains the working of swimming touchpads.
Thank You for the Error
In the 1960 Olympic swimming tournament, the US team thought they had been on the wrong end of a gaffe by the timer, when Lance Larson had to be content with silver in the 100 m freestyle. Touchpads had not been accepted by the majority of sports coaches in the US before the incident, but they became popular after outcry over the rankling Olympic defeat.
Touchpads are mainly associated with touchscreen electronic gadgets such as laptops and mobile phones. But they also serve other important purposes. One of them is competitive swimming.

Electronic touchpads are used in all major swimming competitions to keep score of the timing. The basic principle is the same: when a swimmer touches or sets off from a touchpad, the touchpad is triggered and starts (or stops, depending on its function) the timer.

Before the advent of electronics, swimmers used to be timed manually. This was obviously pretty inefficient, and shockingly inaccurate. This led to automatic timers that were triggered when the swimmer touched it. The earliest touchpads in swimming were crude devices (still much more accurate than human timers), but modern ones are brilliantly unerring, efficient, and sturdy.
Types of Touchpads used in Swimming
There are two main types of touchpads used in swimming competitions: Starting Block Pads and Lane Pads.
Starting Block Pads
Starting Block Pads
Starting block pads are installed in the starting blocks from which swimmers start their laps. They are pressure-sensitive, and are triggered when the pressure of the swimmer standing on it is lifted as he/she jumps.
The starting block pad is crucial in relay runs, where it needs to determine whether a competitor started his lap before the previous one completed his. Despite this, it is not used to determine false starts in solo events. False starts are decided through visual cue by referees, and the starter block pads are merely used to provide the reaction times of the swimmers.
Lane Pads
Lane pads are installed on swimming pool walls, and are used to time laps. It is designed to trigger the timer when the player touches it, and yet, remain unaffected by the constant movement of water all around it. It is made of stainless steel, aluminum, or plastic. It is sometimes coated with a smooth surface, to prevent injury to the swimmers when they kick off from it. Lane pads differ from starting block pads in one way; lane pads have to be, and are thus, designed to be portable and lighter than starting block pads.
Lane pads can also show split times, triggering the timer every time it is touched. Lane pads are also used as lap counters. Every time the competitor kicks off from the pad at either end of the pool, 1 lap is deducted and the remaining number is displayed.
History of Touchpads
Swimming touchpads were invented by Bill Parkinson, Emeritus Professor of Physics at the University of Michigan, in the mid-1950s. In those days, timing and refereeing swimming was a messy affair. There used to be 3 timers and 2 judges per lane―amounting to 30 adjudicators on a 6-lane pool, not counting the starter and the referee! Obviously, however many timers worked to get the timing right, it was an inevitable fact that the splashing and the sheer crowding made it an unenviable task.

Parkinson constructed his first design as a rubber pouch filled with insulating silicone (not to be confused with silicon) oil and having copper wires sewn into it. The copper wires were connected to the timer. The silicone oil had a density slightly less than water, so the contraption partially floated when immersed. This was important in order to register timings, regardless of whether the swimmer touched it under or above the water level.
The University of Michigan started using these devices in collegiate meets in 1957, but other coaches and lawmakers were less than welcoming. It was not until 1962 that the NCAA authorized the use of Parkinson's touchpads. The 1968 Olympics, held in Mexico City, was the first to use touchpads in swimming competitions.