An electronic metronome

I am retired and live in a small apartment, so the days of having large workshops and rooms full of electronic bits are all gone. I do occasionally build a little gadget or a box though, just because I like doing that. As my current preoccupation is learning to play the bagpipes, most of the things I have made lately are to support my music making.

Metronome circuit diagram

I needed a metronome to provide rhythmic clicking sounds and flash LED lights in time to the music, or rather to keep me playing at the speed the music should be played. 

One can of course just download a metronome app on one’s cellphone but that is not in the spirit of building things. So I scratched available components out my spare parts box and reassigned a plastic container from my kitchen to build the thing into. Here’s how it all went together. Above is the circuit diagram. It is a  pretty standard design except that component values have been selected for this specific purpose.

Board drilled inc 555I used ‘Veroboard’ to mount the components onto. It consists of copper strips on the surface of an insulating board. The strips can be cut into sections using a drill, This provides wires that connect those things that need to be connected. Here’s a view of that process. The components mount onto the other side of the board and their wires are poked through holes in the tracks and soldered to the tracks.

Here is a view of  the underside of the board with all the components soldered into place. The purpose of the terry clip is to hold the 9V battery. The holes in the corners are for mounting screws. The wires you see connect to the controls which are mounted on the lid of the plastic box. Nothing is mounted to the bottom or sides of the box , so the whole thing can be accessed by simply removing the lid from the box.  Board underside soldered & bat clip compHere is a view of the component side of the board. It is shown in the maintenance position where everything can be accessed. During operation it moves inside the box next to the speaker and above the controlks so the box can be closed and clipped together.  Top of board in maintenance position

Here is a view of the whole unit, assembled and ready to operate. There is an ON/OFF switch and the click speed and volume can be set on the controls.

Completed unit - angle shot

My Blog does not support videos so I cannot show you how it looks and sounds. But because it makes a cheerful clip-clop sound at the pace of the music, I have nicknamed it “Pony”.



Chapter 2
A friend of mine once learned to do morse code and I also used to do that when I was a practicing Radio Ham. So the friend asked if I could build an oscillator which we could use to practice Morse code with. But a code oscillator is nothing different from a metronome except that it runs about 1 000 times faster. If I set the metronome to run very very fast, the rapid clicking sounds to the human ear like a musical or whistling tone. Click here t6o get the effect.   The metronome controls don’t adjust the speed of the clicking to go that fast, so I just added a switch to the top which switches in different timing components and turns the metronome into an oscillator. I then also installed a jack socket on the box (not jack-in-the -box), into which I can plug a morse key. It is just a contact on a spring loaded arm and when you tap the contact arm. it completes the circuit and sends out a burst of tone. A short burst becomes a dot and a longer burst becomes a dash. The metronome speed control becomes a pitch control to vary the note it gives out up  and down the scale.

Here are the Morse code alpha-numerics in case you would like to practice your Morse code. LOL.Morse code

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