Cheap calculator hack

I put together a Solarbiotics Magbot Pendulum and it has a period of one second. I measured this by using a stopwatch and counting the swings for five minutes. . What I would like to do is count the number of times it swings back and forth over an extended period of time, for example 24 hours.   I came across an article showing how to use a cheap calculator to count the number of turns a shaft makes. A cam attached to the shaft presses the "+" key each time the shaft turns one full turn. to use it, you clear the calculator and press the "1" button. Then every turn the cam presses the "+" button and 1 is added to the sum being displayed. Every cycle of the pendulum causes the LED to flash (pulse)  once. I'd like to use these pulses to do the electronic equivalent of pressing the "+" button.  It might be possible to count these pulses using electronic circuitry (decade counters) but electronic calculators only cost about a dollar of two and I'd like to give that a try. Any suggestions would be appreciated.

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RavensCraft3 years ago
A reed switch placed under the coil might work.
Then just wire the switch to the "+" key contacts
Kiteman4 years ago
You could wire the contacts of the + key through a transistor, and use the pulses to trigger the transistor, momentarily closing the switch.
very innovative... its so simple, right there in your face.... but it would not have occurred to me..lol
A calculator would work if you added a push pull circuit where the pendulum swings one way and triggers 1 and when it swings back the other way it triggers +. That way for every complete back and forth swing you get a count of 1 added to the total.