Category Archives: Housework

Pocket Preservation: Keyless Entry and a Silicone Sheath

I wear nice pants (often suit pants) to work, and had more than one suit have the pockets reach the end of their useful lives long before the suit was otherwise showing signs of wear. The culprit was my keys and keyring, which would also scratch other items in my pockets. I eliminated most keys by shifting to keyless entry where possible, using number pad locks on doors at home and using the keyless entry fob for my Prius. The one key I couldn’t easily eliminate was my office key.

A few winter breaks ago, I took on a project to address this. I decided to turn my office door handle into a capacitive touch sensor. I programmed an Arduino to sense the secret sequence of taps on the outer door handle. In response, a motor pulled down the inner door handle and thus unlocked the door. It worked perfectly, until I tried it with the door closed. I turns out my office’s metal door frame grounded the handle, so the capacitive touch “interface” of the door handle only worked when the door was open. While there were some fun possibilities to address this while still using the Arduino/motor approach, that winter break came to an end before I had time to try them.

In the interim, I found a solution which has been appealing enough that I’ve prioritized other projects over returning to the Arduino door handle. The interim solution was to buy a silicon cover for my one remaining key, preventing it from sawing into my pants or other pocket items.

I’d like to get away from carrying things altogether, so I may eventually invest in an after-market keyless entry number pad for my car and may return to the Arduino door handle project eventually.

Removing Stamp Ink from a Wall

Our address stamp

We had a six children (including ours) in our house over the weekend and one of them found our return address mailing stamp (we use this one, which has served us well for several years so far). The kid did what kids do, our wall got redecorated, and I got the opportunity to do an experiment.

I found a wide range of advice online and decided to go with the recommendation here to (1) apply white toothpaste, (2) let it sit for 10 minutes, and (3) wipe it away with a wet white washcloth, repeating if necessary.

I was quite surprised to see how well this worked. I did not need to repeat the process; the ink was completely removed after just the first round of steps.

The toothpaste fully absorbed the ink, so wiping the toothpaste took the ink with it. As far as I could tell, the toothpaste wasn’t serving as an abrasive (which is how dry toothpaste is sometimes used in car scratch repair).

The toothpaste I used was Colgate Total Advanced Whitening, which was just what we happened to have around.