Wednesday, September 25, 2019

Aitendo kits

One of the things I usually do when I go to Akihabara is to visit the Aitendo electronics store. Aitendo store kits are very reasonably priced and there is a great variety. Note that I have already talked about other kits in the past, check the FM microphone and Achandeino. In this post, I wanted to introduce two new kits that I bought and I liked them.

The first kit is a hearing aid circuit (補聴器キット Hochōki kit).

As you probably guessed, the circuit captures sounds through a microphone and amplifies them with a transistor. The user with hearing problems listens to them through headphones.

The second kit is a Tesla coil plasma speaker (テスラ電光音発生器 Tesura denkō-on hassei-ki). By the way, there are now other Tesla kits with larger coils.

This circuit is somewhat more complicated to explain. Basically, it is a high-frequency oscillator that accumulates energy in the coil. The oscillator wave is amplitude modulated by another input wave, for example, music. Bringing a screwdriver to one end of the coil produces an electric arc discharge and makes noise. That noise when modulated by the song turns the coil into a speaker.

It is best to see it with your own eyes. Watch the video I recorded.

You can also use the kit to light a fluorescent lamp.

Saturday, February 23, 2019

Kung Fu movies

If you were born in the early 80s, then there is a reasonable chance that you were a Kung Fu films lover like me. I remember myself going every week to the video rental shop to check if a new Kung Fu film had arrived.
The first Kung Fu film I watched was "Incredible Kung Fu Mission" (Shi xiong shi di zhai chu ma) created in 1979. I watched it by chance when I was about 6 years old and it was in Betamax format. Probably the only film I've watched in such format. This is the quintessential Kung Fu movie, I really like it.

One of the things I like the most about Kung Fu movies are those crazy jumps. They actually have a name in chinese 轻功 (qīnggōng) which is a useful keyword to look for images on Google.

Electric street light switch

When I walk on the street, I often try to spot devices that make our lives easier without us knowing. If I stop for a second and look around, I usually found myself surrounded by a lot of stuff that I don't always understand or pay attention to.

For example, I found this weird looking device inside a cabinet on the street. I took a picture of it to look it up on the internet later. It turns out that this is an electric street lamp switch (called EE switch by Panasonic). In other words, a device that automatically regulates the current that goes through a street light based on the ambient light.

Wednesday, February 13, 2019

Fixing my Sunto wrist watch

I rarely wear a watch nowadays. Most of the time I prefer to use the phone instead to tell the time. However, sometimes I like to dress up and wristwatches are nice accessories that make you look better.

Unfortunately, my otherwise excellent Suunto watch wasn't looking that good with all those scratches. I needed to get rid of them. Fortunately, during the last few years, I assembled quite a few plastic scale model kits and learned a few tricks along.

To remove the scratches from the Suunto surface, I first applied a fine-grained (number 1000) piece of Tamiya sandpaper. Remember that the higher the grit number, the finer and more polished appearance you get.

Once I removed the main scratches from the surface, I applied Tamiya polishing compound with a cloth multiple times. I didn't know about compound until I built this Greyhound scale model.

The end result was quite satisfying. The crystal was now transparent and smooth, just as I wanted. I also replaced the battery and the O-ring with Suunto battery replacement kit.