Why use a Zero Ohm Resistor? Assembling the Electric Piano / Electronic Organ DIY Soldering Kit

In this video I assemble a the Electric Piano / Electronic Organ DIY Soldering Kit from AliExpress.
AliExpress (exact item): https://s.click.aliexpress.com/e/_c3lWGb37

The 555 timer is used as the basis for an oscillator. Each switch further to the left increase the amount of resistance in the circuit. By varying the resistance we vary the frequency at which the timer oscillates, and the sound that is produced.
LM555 datasheet: https://www.ti.com/lit/ds/symlink/lm555.pdf

Unusually, the kit uses a 0 Ohm resistor. Typically a jumper wire, often made of a trimmed-off lead, would be used; however, here we are using this special component. The use of the resistor is extra unusual as the designed could easily have connected the traces on the board directly. Interestingly, it seems that in some other variants of this kit other values of resistor are used to vary the tones that the keys produce -- which may explain the curious use of this component.

You can experiment with the circuit using an online simulator. Note that I have replaced the 0 Ohm resistor in the circuit with a 1 Ohm to avoid issues with the simulator.
Simulation: https://tinyurl.com/27gmk3cj

As this is a simulation, it works in less than real time and you have to chose to play back the audio by using the "Play Audio" button. First you close any key switch or switches you like and it will show you the waveform in the "scope" and record the tone to a 10 second sound buffer. Bear in mind that the simulation is around half real speed, so you may need to hold each switch for longer than expected.

While the simulation works correctly, the physical version shows a slightly different operation. While generally the kit seems to work as expected, the final two keys don't seem to produce audible tones. This may be due to the frequencies being produced being too high for my hearing. If you can hear them, let me know in the comments!

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Видео Why use a Zero Ohm Resistor? Assembling the Electric Piano / Electronic Organ DIY Soldering Kit канала Jason Jacques