Siren DIY (bending, hack, drone ...)

My first siren, tinkered with my old bike siren when I was a kid

like this one
Sans titre

(but an old one with real resistance easy to exploit, this one have certainly a black blob inside, but it is just to illustrate the type of toy)

4 select sound (laser, speed, long, 2 tons)

add :
switch on/off power,
voulume pot,
bass pot,
treble pot,
loop switch,
momentary push switch
pitch pot 1
pitch 2 / LFO mix pot ( ? i don’t see how it is possible but it works like that)
switch on/off LFO
Rate led LFO
Rate pot LFO
and add an old pedal delay (bypass switch, level, time, feedback)

555 circuit for LFO with vactrol, a passive tone circuit and all in a sort of cake metal box
Work on 9v power supply

cheap but fun :slight_smile:


Very nice and well played too!


Another one, a Drone Siren with more fonctions

A generator of sound with 555, an optical envelope with 555 , a PT2399 delay, a mini sequencer 4 step with CD4017 and 555 timer, an LFO with vactrol, volume, hold, loop … and some push switch for pseudo arpegiator

spaghetti with 7 littles circuits in a wood box that i made

Work on 9V power supply

some schems

Optical Envelope


PT 2399 Delay

apc organ toy


Drone based on a CD40106 and a CD4040, installed in an old ohmmeter found in flea market

    Switch on / off
    Led on power
    Volume pot
    Switch on / off oscillator A
    Pot pitch osc A
    Switch on / off osc B
    Mini switch select sound 1 or 2 for B
    Pot pitch osc B
    Switch on / off osc X
    Pot pitch osc X
    Switch on / off LFO for B
    Led rate LFO for B
    Pot speed LFO for B
    Switch on / off LFO for A
    Led rate LFO for A
    Pot speed LFO for A
    Mini switch select Square or Saw wave LFO for A
    Pot Filter for A
    Switch on / off rhythm sequences
    Select switch A or B for rhythmic sequence
    Push switch changes the rhythm of the sequences
    5 banana cards for various rhythmic changes
    Jack out
    Power socket for tansfo 9V

Stunning, visually and aurally. Thank you.


Wow! Yeas, what @Bitnik said. Loved it!


A bit curious on how you’re using the counter, and also what kind of filter you’re using. Do you have schematics?


This is stunning. Well done!


I need this in my life. My goal is to torture my brother and sister by making the noisiest most annoying toys for my nieces and nephews.


(while we’re waiting for @dud :slight_smile: you may want to check out the Alien Screamer and Weird Sound Generator (WSG) over at


yes. it’s in the list. RWs schematics are great. I appreciate how he labels and numbers the legs of the components. I breadboarded an LFO of his and it was super easy to follow.


Mmm, well, trust but verify? If you look at potentiometer R1 at the top of this it has legs 1 and 3 reversed. I didn’t notice until after I’d gotten a PCB fabbed. For Wilson it wouldn’t have mattered because he wired all his panel controls but I had PCB mounted pots… failed to check them (his 2 and the 3 attenuators I’d added) and got 4 out of 5 wrong. Nice filter though, once I corrected my PCB.


there’s no filter, it’s sync between 2 osc with CD40106

one osc




the vid of Casper Electronic about that

part 1

really the simplest osc in the world :slight_smile:


I found my notes from this project, because I don’t have a complete schem, it was tests and mix with several schem

it’s a bit of a mess but here it is


Superb! It does sound a bit like the inside of my head though :exploding_head:


Ah, cool, makes sense now that I see it :grinning: But the CD4040? Are you feeding that with one oscillator and tapping different subfrequences?

(guess I should listen to the entire video again, was fighting with dailymotion’s controls last time so may have missed parts of it :upside_down_face:)


sorry, to be honest i don’t know what i did at the time with the CD4040, maybe a mini patch bay for different divisions for the LFO rythmics ? mystery mystery …


I imagine the CD4040 + a rotary switch would give you an even 12 oct split, if you get the frequency range right. You would just need to make sure that you give enough ways to tune the higher and lower frequencies such that the highest frequency and the lowest frequency are 12 octaves apart (If you use all stages).


yes it’s like a CD4024, but here it’s seems that i use it only for rhythmic with combination of several out of the CD4040 to make some little “sequence”


No problem for me, I managed to build your PT2399, it will be a walk in the park :stuck_out_tongue_winking_eye:

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