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Episode 375: Hacked Fetal Detector Music Synthesizer

Hacked Fetal Detector Music Synthesizer

element14 Presents  |  MAYER MAKES VCP Profile  |  Project Videos

 

Fleamarkets can hold a lot of junk but also treasures, Clem bought a 70's medical device which was used to examine the heartbeat of unborn children and hacks it into a retro style synthesizer.you can use your own heartbeat or even that of any person(born yet or not) to alter the sound of the device. It features a 10 Stage Sequencer and 5 different filters to create various sounds and rhythms.

 

Bill of Material:

 

Product NameQuantity
Buy Kit

555 Timer IC DIP8

3Buy Now

SPDT switch 5A Panelmount

20Buy Now
10 Turn Potentiometer 5kOhm1Buy Now

Decade counter/Divider IC

1Buy Now

Knob Round 6mm / 50mmm with position marker

1Buy Now

Quad Amplifier IC

1Buy Now

Ansmann NIMH AA 1,3Ah 4-Pack

2Buy Now

Resistor 10kOhm

10Buy Now

Resistor 33kOhm

10Buy Now

Electrolytic Capacitor 10uF

2Buy Now

Electrolytic Capacitor 100uF

2Buy Now

 

Additional Parts:

 

Product NameQuantity

Fetal Detector from the Fleamarket, or get a new one for cheap on the internet.

1

Order a wild selection of Caps and resistors to experiment around until you get the desired sound.

1

Differently colored wire to keep track of all the connections.

1

 





Anonymous
  • in reply to jimlberto

    I wish I could just post them or give asingel link, but I made up the circuit as I built it and changed a lot over the course of the project but here arethe circuits i took as a starting point, I doubt you migrth get a hand at the same Fetal detector but maybe some different piece of old tech to utilize so these links should help you:

     

    https://lmgtfy.com/?q=Atari+Punk+console+circuit&s=g

     

    Basic sound generator I used 2 of these to get a high and a low note,( the low is nearly unhearable in the video)
    the Pitch pot is connected to the main big poti i built into the machine

    https://lmgtfy.com/?q=Baby+step+sequencer&s=g

     

    The sequenzer part is based on this circuit , I only added LEDs and connected inputs and outputs to the other sections of the machine

    https://lmgtfy.com/?q=Low+pass+filter+rc&s=g

     

    The FIlters are just Low Pass R/C filters(a cap and a resistor) in random values, trial and error showed me some that sounded interesting.
    the Fetal signal gets mixed into the added electronics just before the Sequenzer stage. the sequenzers signal is fed back into the sound generators when the "Feed" switch is activated.

    Hope  this info helps you in building your own noise machine!

  • hi, is there a way to see the actual schematics of this project? 555 to 4017 to 324 plus resistors switches and wires, is not quite specific, you know?
    maybe you can point to a link where I can set the pieces together without making a mistake? perhaps?

  • in reply to beacon_dave

    I actually made something similar to that a while back:

    :

    https://www.youtube.com/watch?v=CcfS_xI3Pdk

    it uses 2 555 timers and a FLed as a crude form of a 2 step sequencer, you can alter speed and pitch with covering the photoresistors and the fled, modulate with covering the speaker and activate the sound with the pushbutton

  • in reply to mayermakes

    How about something like this 'playWATCH' synth:

     

    https://www.hackster.io/janost/the-playwatch-61db7b

     

    but incorporating an IR photoplethysmography pulse sensor into the design to trigger it from heartbeats ?

  • in reply to mayermakes

    Excellent! You're an engaging host with a knack for explaining things.

  • in reply to aptbartmess

    Thank you! Well if you insist I'll think about some future projects with experimental instruments, maybe something with MIDI or homemade guitar effects.

  • What a super project! I'd love to see more of your experiments with sound making instruments.

  • in reply to beacon_dave

    thanks I got to take a look at that!