How to make a "mechanical access counter" to physically count the number of site access

If you were familiar with the Internet about 2000 years ago about 15 years ago from now, if you are planning to visit "Access counterThere are many people who remember. I am happy and glad about the number of counters that are increasing every second,Kiri numberHit "Kiri GethoosezaI think that there are many people who have an auspicious experience who wrote in the book.

Analysis tools such as Google Analytics are now widely used for page access analysis and counters that simply count the number of accesses have completely disappeared,SpriteJeroen Domburg has developed a method of counting the number of website accesses by using a physical counter and is open to the public on the net.

Sprites mods - Mechanical webpage hitcounter - Intro

One day, the mechanical counter obtained by Mr. Sprite is the following picture. I thought that this must be a mechanical counter, looking at two lead wires extending from a black square box and a rotary type drum, which was in a bag that I was going to receive from a friend and thrown away. It is said that. This counter, on two lead wirespulseWhen the electric signal of the form is added, the drum on which the number is written rotates and the number increases.

Sprite, who saw this part, took advantage of its appearance and said, "I wanted to make access counters that I often found when I started the Internet." Moreover, there seems to be another merit other than appearance by using this counter. That means that the "clicking" sound that actually sounds when this counter moves and the number increases will inform you that someone actually accessed the page. This is a very easy-to-understand motivation, Sprite immediately created a circuit diagram and started making real counters.

That's why the circuit diagram created by Sprite is. Parts indicating counters are written in the upper right, and other circuits are simple circuits, each including a transistor, a diode, a resistor, and a capacitor.

The mechanism that the counter moves is as follows. The part written "3" "7" "4" at the left end is connected to the server machine managed by Sprite, and when it detects access by creating a dedicated program, it outputs electric signal. Then, the outputted signal enters the transistor and is amplified to convert it into a signal for operating the counter.

Specifically, this counter is said to be a part that operates at a voltage of 24 V (volt). However, in general, the voltage that a PC machine can handle is at most 5 V, and it does not depend on the required voltage. So, Sprite's eyes turned on can output 20 mA current at -10 V and +10 VSerial port,So-calledD-sub terminalIt was a port that used.


Nonetheless, using either the + 10V or -10V terminals does not reach the 24V that you originally need and the current capacity of 20mA is not enough for what the counter needs. So Sprite introduced a secret strategy. By using both the 3-pin "+ 10V terminal" of the D-sub terminal and the 4-pin "-10 V terminal"I managed to create a voltage difference of 20 V at which the counter operatessomething like. Moreover, it succeeded also to clear the upper limit of the current of 20 mA by charging and discharging by inserting a capacitor between both terminals. Furthermore, using an NPN type transistor BN 550,Switching (on / off) 20 V electrical signal with signal from 7 pinBy doing so, we have created a mechanism that gives the signals necessary for the operation of the counter.

So to speak, the audio amplifierPush-pull methodThe only concern is that the polarity of the capacitor is reversed when the pin 4 turns to a plus when the 3 pin is minus,Capacitor ruptureTo the situation. However, since the flowing current is as small as 20 mA, it seems that we decided to omit the protection circuit.

Based on this circuit diagram, it is the following circuit that the level of simplicity was manageable even if soldering the parts directly without using the printed circuit board. By the way, in this picture there are light blue tubular capacitor, black transistor, blue and striped resistance, but only the diode can not be seen. This seems to be because it is built in the counter body.

And the fact that the counter was actually installed on the table looks like the following. Although it seems that it can not see how it actually operates, it was content that surely makes sure that it is moving.

In addition, I wrote the signal exchange using the D - sub terminal in LinuxdaemonIt is controlled by the program (program). Daemon is distributed under the GPL license,from hereIt seems that downloading is possible. (Download compressed file by clicking)

In addition, on the page of source Sprite, I am looking forward to the report from the person who actually created the counter. The page was released in 2007, but also from the appearance of comments from time to time even as of 2015, it seemed to be a glimpse of how regulars gathered regularly.

in Software,   Hardware, Posted by darkhorse_log