Raju Dantuluri


Every problem has an equal and neat solution

Growing up I was fascinated by weighing machines.

We now live in an era where one's weight is serious business. Where weight control is a national fad, and people have nightmares about bathroom scales.

But back then checking your weight used to be just fun --- and nothing more.

I remember the day my father let me weigh myself for the first time, in Bangalore's Science Museum. He gave me a quarter, cautioning me that I should insert it only after the small red-white disc had stopped rotating --- else, the machine would print incorrect weight.

I climbed on and, after the disc finished its run, put in the coin very carefully. The machine went tat ta-ta ta-ta tak and a card popped out. It read '23'.

Much later, one fine morning at the Visakhapatnam railway station awaiting my father's train, I discovered an interesting thing about coin-operated weighing machines.

As I was preparing to weigh myself, a man tapped me on my shoulder. He said he could tell me my weight without wasting a rupee.

I didn't believe him. But still, out of sheer curiosity, I asked him to go ahead.

He made me get off the machine, peeked at its inwards from the side, then asked me to get on again. After the red-white disc stopped, he once again peeked into the machine.

"Fifty-five," he said.

My weight was somewhere in that vicinity, but I thought he was simply guesstimating. So I inserted the coin, ready to prove him wrong.

Tat ta-ta ta-ta tak went the machine, and out came a card. It read '55'!

I asked the Good Samaritan how he had managed the feat. He told me.

The machine, it seems, has a big disc inside marked 0 to 120, with .5 midway between two numbers. When you get on the pedestal, the disc rotates according to your weight. And when you insert a coin, it prints the weight the disc shows on a card and spits it out. Pretty simple!

A rotating small red-white disc indicates the inner big disc is not yet steady to print. So all you need is to stand by the side of the machine, ask your 'customer' to get on, and see what number the inner wheel shows!

The only difficulty is the numbers are etched wrong side up, so that they print properly.

Later, I found out a way to weigh myself without anyone's help. Since that day I have not used a coin on weighing machines, nor let anyone with me use one.

Initially, people didn't believe me when I told them their weight, and used to waste money to check, just as I did that day in Vizag.

Over the years, I have seen many people cheating the machine. The manufacturers realized the flaw and began trying to plug the, well, peek hole. An obvious, not to mention crude, attempt was when they put cardboard on the sides to block the view. But none of their workarounds really succeeded, and people continued to cheat.

A few months ago at the Bangalore railway station, my aunt wanted to check her weight. After she climbed on, I found the numbered disc was not rotating. We thought the machine was faulty. But a little later, a man inserted a coin and out popped a card.

"So the machine has finally beaten you," my aunt smiled.

I knew the manufacturers had come up with something new. I asked my aunt to climb on the pedestal again. Only after we inserted the coin did the disc respond.

I realized what had happened. Earlier, whether you inserted a coin or not, the disc used to rotate as soon as you climbed on. And it would print when you inserted the coin.

Now the disc rotates only after you insert a coin, and prints only after the disc inside stabilizes.

The new design has killed two birds with one shot. First, since it doesn't rotate unless you insert a coin, you can no longer cheat. Two, with the old machine, if people ignorant of the red-white disc's indication that the big disc is rotating inserted a coin, it printed the wrong weight.

Now irrespective of when the coin is inserted, the machine prints only after the disc stops rotating --- thus, only the correct weight.

I am happy to be beaten by such a simple design. And I write this diary because this is so closely related to our work.

One bad design leads to a multitude of problems: encouraging cheats like me, wrong weight, cardboard around the machine...

But every problem has a neat solution --- like, rotate only after the coin is inserted, print only after the disc stops rotating.

Raju Dantuluri has taken to carrying coins again.

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