555 Pendulum

Description

To play the game you press the button. The button state is fed in to an XOR based edge detector that triggers a 555 timer. The timer sends a timed pulse to the inductive driver (L293D). The driver drives the electromagnet to make the pendulum move. A down press of the button energises the coil in one direction and releasing the button energises it in the other direction. There's also a separate 555 timer in astable mode. It's generating an adjustable square wave that can be used instead of the button to drive the pendulum. This is kind of like a second game where you have to play with the frequency and duty cycle of the square wave to get the pendulum to swing freely.

Files

pendulum.pdf

PDF schematic

Adobe Portable Document Format - 44.67 kB - 01/04/2022 at 02:47

Preview

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pendulum.zip

KiCAD Files

Zip Archive - 163.86 kB - 01/04/2022 at 02:47

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Components

1 × Push Button

2 × 555 Timer

1 × 74LS86 XOR

1 × 74HC04 Hex Inverter

2 × Potentiometer

Project Logs

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Summary
dennis1a4 • 01/04/2022 at 03:13 • 0 comments

I've had this idea for a pendulum game for a while. I like how there's very little you need to know to play it. There's only one button, and pressing or releasing it energises the electromagnet either one way or the other. I built it out of parts I had on hand. That is the reason for some of the odd passives value choices. The bearing for the pendulum is from an old hard drive. The electromagnet is an old bolt with wire reclaimed from a VCR head. I had some extra Gateron brown switches and printed a one switch holder. The base is made from a small scrap of plywood and some pine.

In the future I'd like to have a larger pendulum in my shop hanging from the wall. This is a good test bed to get things started and try different circuits. I'm also thinking of adding a line of LEDs to create a POV display. It could display the highest angle achieved.

The KiCAD files and pdf schematic are included in this project entry.
Rebuilding from Schematic
dennis1a4 • 01/04/2022 at 03:02 • 0 comments
Getting it to work
dennis1a4 • 01/04/2022 at 02:59 • 0 comments
Building the Base
dennis1a4 • 01/04/2022 at 02:54 • 0 comments