Audio Frequency Music Box Comb Filter

Jeri and Monty make an audio frequency comb filter from music box parts, lasers and piezo transducer. Each tab on the comb vibrate at a specific frequency and can be seen or heard with a light to sound circuit.

Category:

Education

Tags:

• Jeri Ellsworth
• Music Box
• Filter
• Fat Man and Circuit Girl

[daveduley]

This is a very old technique and was used in remote controls for RC planes and the like in the 1960's. The RC reciever had a comb with contacts on the ends. The controls for the radio would send out audio frequencies that were recieved in the model plane and used to magnetically stimulate the comb. The vibrating fingers of the comb would make and break to an adjacent contact. This was then fed to the servos that moved control surfaces etc. The old Heathkit radio controls worked this way

[jeriellsworth]

@daveduley Engineers were so smart back then. :)

[jeriellsworth]

@daveduley Engineers were so smart back then. 

[imfree707]

Tone (detection) reeds in pagers worked by audio resonance that way! Each reed was a micro tuning fork, cut to frequency, with a piezo drive transducer on one tine and a pickup on the other tine!

[DugGLe55FuR]

I think you're amplitude was too high, when you finally hit the resonating frequency of the individual tine exactly it was bending the base of the comb to the point where the neighboring tines were vibrating as well.

[swirlingabyss]

Marry me circuit girl.

[bangulo2012]

Your guys inventions are a amazing!... a laser pick up would be the best sound!!