Making a “ROM eraser” with a germicidal lamp to visualize how the ROM is erased

In the past, an experiment was conducted in which a sterilization light bulb was attached to the “E17 socket” and lit.

Now that I know how to light the sterilization light bulb, I will make a “ROM eraser” with this sterilization light bulb.

Making a ROM eraser

Constant current driver built into socket

I have an E17 socket for a germicidal light bulb and a 1W LED driver.

E17 sockets are sold at home improvement retailer.  The 1W LED driver is OSMR 16 – W1231.

When I tried it with the LED driver in the socket, the capacitor was sticking out.

I removed the capacitor and extended it by wiring.

If the wiring is too long, the noise will increase, so the length is minimized.

The LED driver fits nicely into the socket.

I made 2 ROMs in the cassette of the Nintendo-Famicom, so I made two so that I can erase two ROMs at the same time.

Processing of the storage case

Next, I processed the storage case. Acrylic blocks ultraviolet rays, so I prepared an acrylic case. I bought a stack-able acrylic desktop box in a Japanese store called “MUJI.”.

Drill a hole.

Acrylic is easy to melt, so set the rotation speed of the drill to a low speed and make a hole.

Also, if the blade is caught or pushed too hard, it will crack immediately, so open it carefully and slowly.

When the hole is open, screw the connector and socket together.

DONE!

It was pretty good.

It lights up when the AC adapter is connected to the rear connector.  I used a 24V AC adapter this time.

Let’s light it up as a trial.
The light of the ultraviolet lamp is beautiful.
Acrylic blocks ultraviolet rays, but it doesn’t cut them completely, so it’s not good to see them for a long time.
But it’s beautiful.

ROM erasing experiment

Writing data with a ROM writer

Write the data in the ROM with the ROM writer I made before.

UV-EPROMは、消去された状態のROMは全てのビットが1になっています。読み出すとFFが読み出されます。今回は、愛犬エヴァちゃんの画像が入ったROMと、全て0を書き込んだROMを用意して、消去しながらデータがどう変化するか、調べてみます。

Erase Started

With the ROM connected to the ROM writer, place a “ROM eraser” on it, and  read the contents of the ROM while erasing the information in the ROM.

I made a ROM write / read program with processing.
This software reads and visualizes the contents of the ROM every 1 minutes.
Indicates that white is erased.

Let’s see how the erasure works

The number in the upper left of the figure below shows how many minutes it will change.

After 1 to 11 minutes ↓

This is the image data of my dog being deleted. I can see that it disappears all at once from about 5 minutes. This ROM was the first ROM to write data during an experiment, so the trace is a black pattern on the top of the image.Also, there is still a bug in the reading program, and the image is a little shaky.

This is the ROM with all the data filled with 0.
This also disappears from about 5 minutes.

I see the vertical lines, but I can see the unevenness in the way of disappearing.

It is almost white (erased) in about 11 minutes.

These experiments show that the ROM is completely erased after about 15 minutes of irradiation.

The ROM eraser is completed!

I found that the ROM eraser that I made worked normally. This will allow you to write data to the ROM and experiment with it. The glow of the ultraviolet light bulb makes me feel the future.

Here is a convenient sterilization light bulb ↓.

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