Abhishek Kar

SE367: HW 1

How do I open a lock?

I open the lock on my room door every day and what seemed to be a pretty simple task till date turned out to have some intricate details.

The first step is to find the key corresponding to the lock. I use a lot of cues to identify the key corresponding to the lock in the keychain. Some of them include the the size, visible age of the key, the deformations etc. Ironically I never use the branding on the key and match it with that on the lock. If its a lock that I am fairly acquainted with, I notice that I dont even have to conciously search for the key. For example of its a comparatively big key, I can just decide on the right key by feeling the cuts on the fore end of the key. If I have multiple keychains in my pocket, the label on the keychain and the number of keys in the keychain help me in deciding on the correct option.

The next step involves taking the key to the lock and inserting it into the keyhole. The first task is to align the casing on top of the keyhole so that the key actually goes in. I try inserting the key in the usual manner at first and if I fail, I try to align the casing with the key itself but turning it with the top of the key. I dont use my fingers/bare hands. I try doing the above in a subconscious manner a couple of times and only look at the lock if I fail.

The final step is to rotate the key. Most of the times the motion is smooth but it gets a bit difficult with older rusted locks. I automatically apply a more torque once I face resistance. The sensory feedback on my fingers pads triggers this action. I try to make a jerking action to force the key. With newer and “smoother” locks, I know that I have got it open once I hear the click. With older locks, I realised that I pull on the lock even after rotating the key a full 360 to get it open. Another peculiar habut with me is to open the latch and put the lock back in the same position. I always grip the lock at the same place too. Another small thing I noticed is that I tend to confuse about the rotation direction (clockwise/anticlockwise) when I do it either with my left hand or even backwards!