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Hah! You found a typo! During breadboarding I used 100k and later went to 50k, because the increased resistance messes a bit with the DC setting at the emitter of Q2, due to base current. Just use a dual 50k but breadboard first, you might want to adjust C3 and C4 or other values here and there. Good luck & thanks!

Thanks. It should work right out of the box. This is my simulation code that works with ngspice:*** RC Chaos Generator **** Supply vcc 1 0 5.0V* CircuitR1 1 2 5kR2 4 7 15kR3 2 6 30kR4 6 0 47kR6 2 3 5kR7 3 4 10kR8 4 5 10kC1 3 0 1nF ic=1.290847C3 4 0 1nF ic=0.676498C4 5 0 1nF ic=0.645246C2 6 0 360pF ic=0.607691Q1 2 5 0 BC547CV2Q2 7 6 0 BC547CV2.model BC547C NPN(Is=32f Xti=3 Eg=1.11 Vaf=100 Bf=720+ Xtb=1.5 Br=6.313 Isc=138f Nc=2.053 Rb=1.3k+ Ikf=500m Ise=230f Ne=1.583 Nk=1.05+ Ikr=.187 Rc=.4216 Cjc=5.25p Mjc=.3147 Vjc=.5697 Fc=.5 Cje=11.5p+ Mje=.3333 Vje=.5 Tr=10n Tf=410.7p Itf=2.204 Xtf=66.65 Vtf=10).model BC547CV2 NPN(Is=7.049f Xti=3 Eg=1.11 Vaf=24.76 Bf=543.1 Ise=78.17f+ Ne=1.679 Ikf=94.96m Nk=.5381 Xtb=1.5 Br=1 Isc=27.51f Nc=1.775+ Ikr=3.321 Rc=.9706 Cjc=5.25p Mjc=.3147 Vjc=.5697 Fc...

Thanks. It should work right out of the box. This is my simulation code that works with ngspice:*** RC Chaos Generator **** Supply vcc 1 0 5.0V* CircuitR1 1 2 5kR2 4 7 15kR3 2 6 30kR4 6 0 47kR6 2 3 5kR7 3 4 10kR8 4 5 10kC1 3 0 1nF ic=1.290847C3 4 0 1nF ic=0.676498C4 5 0 1nF ic=0.645246C2 6 0 360pF ic=0.607691Q1 2 5 0 BC547CV2Q2 7 6 0 BC547CV2.model BC547C NPN(Is=32f Xti=3 Eg=1.11 Vaf=100 Bf=720+ Xtb=1.5 Br=6.313 Isc=138f Nc=2.053 Rb=1.3k+ Ikf=500m Ise=230f Ne=1.583 Nk=1.05+ Ikr=.187 Rc=.4216 Cjc=5.25p Mjc=.3147 Vjc=.5697 Fc=.5 Cje=11.5p+ Mje=.3333 Vje=.5 Tr=10n Tf=410.7p Itf=2.204 Xtf=66.65 Vtf=10).model BC547CV2 NPN(Is=7.049f Xti=3 Eg=1.11 Vaf=24.76 Bf=543.1 Ise=78.17f+ Ne=1.679 Ikf=94.96m Nk=.5381 Xtb=1.5 Br=1 Isc=27.51f Nc=1.775+ Ikr=3.321 Rc=.9706 Cjc=5.25p Mjc=.3147 Vjc=.5697 Fc=.5+ Cje=11.5p Mje=.6715 Vje=.5 Tr=10n Tf=410.7p Itf=1.12 Xtf=26.19+ Vtf=10)* PHILIPS pid=bc547c case=TO92* 91-07-31 dsq* Simulations.controltran 100ns 5mswrdata out v(2) v(3) v(4) v(5) v(6)exit.endc.endPlotting column 2 and 4 of the resulting out.data using Gnuplot results in below image.Please post an "I made it" if you get it working. Good luck!

I tried out different models of BC547C, as these differ somewhat per manufacturer. The one I settled for was that model that came the closest to the experimental outcome. Note in the code in my previous post, only one model is actually used.IC stands for initial condition, here initial voltage on the capacitors at t=0. This code was part of a loop to build a bifurcation plot. For each itteration of the loop, a resistor value was stepped and the simulation repeated, taking of in the state (capacitor voltages) in which the previous one ended.

Thanks! Will post some recordings soon. Just have to set up the stuff to record here...

Indeed there was. Somehow a part of the text got disapeared.Thanks for catching that!

Cool! Planning on making an ebook reader cover following your method!

I don't have a good microphone at the moment, but I'll look into getting one (suggestions on type/brand are welcome). Also, some additional info on this circuit can be found at: http://www.madbeanpedals.com/forum/index.php?topic=25587.0 All the best!

Woow! Magnificent, and from the photos it looked like you guys had heaps of fun too!

Good question!People have been debating that for ages. The recently recovered Willis Linsay's travel diaries contain a hint at what might be the beginning of an answer, and I quote: "Ultimately, it is about the entanglement of Mankind, Technology and The Spud. We should not embark on such voyages without tatering [sic] to all three aspects to the fullest of our conscious and unconscious awareness. "Now, you can debate about what this means, my guess is as good as yours, but I'd say use a potato that has grown close to you, since it will give you more entanglement to begin with. Effectively, the advice here is "be the potato".Hope this answers your question. :-)

Thank you! I only know enough to rub two transistors together. I asked my GF if I could be Next. She gave me a confused look and then said I'm the current. Which confused me, because I know for she doesn't know the difference between current and voltage that well. Somehow I think we're one spud short of a stepper here.:-D

Lol, "tropical fish caps"Never realized my Cardinal Tetras were 0.62pF. :-D

Thanks! Good info! I usually just go with what parts I find in my drawers.Be sure to post an "I Made it!" :-)

Thanks! Might do a video in the near future ;-)

"Gum drop" caps. Had to google that one :-). You can use ordinary ceramic and electrolytics here. Or salvage from electroscrap of you really want to go cheap.

Hi,For Europe, most of the components and housing can be bought trough Conrad:https://www.conrad.nl/ The switch is from:https://www.tube-town.netI didn't specify suppliers, because it depends on where you're from. Maybe someone else here can comment on good parts suppliers in the US?

Thank you!

Right. It's one of those 'classic' pedal switches but not sure they are all wired the same internally between different manufacturers. Here's the link with datasheet for the one I used, as in step 5: https://www.tube-town.net/ttstore/Switch/Footswitch-Standard/Alpha-Footswitch-3PDT-Latching::3695.html all the best.

Nice work, Zhollet!

Propellers will probably give you more thrust, when using the motors from the bilge pumps as compared to the bilge pumps themselves unmodified. Regarding speed, that depends on the drag force on your vessel. Just trying it out is the easiest way forward imo.

Thanks, In my case I used a 12V 7Ah Sealed Lead Acid battery. Both relatively cheap and durable. Long time ago, but I built a custom controller using a Microchip PIC and some mosfets. To control the motors from the arduino, you could do the same. PWM them using mosfet(s). Fairly standard electronic practice. :-)

The thruster in this instructables was intended for small underwater robots, not kayaks. It probably won't be sufficient.

Hi, thanks.I doubt these thrusters will be strong enough for that. Maybe build one and try it out to get a feel for how strong they are.

Thank You! Nice Clip. By Playing with the supply voltage and the resistors to Q2, it is possible to get band-shaped chaos too.

Cool use of a 555! Do you think it is possible to get it somehow working without the comparator (maybe at the cost of reduced regulation precision)?

actually, RC model manufacturers offer many propellers designed for boats, from very small (cms) up to 100mm too. check out Robbe or any other RC parts manufacturer. Eagerly awaiting your results...

Thanks! In all likelihood, a single thruster like I built won't be enough to propel a kayak, maybe 4 of them might do it. I'd say: experiment a little and see. Please post the results here.

Thanks Tom!

Thanks! Also, SPICE models differ a bit per manufacturer, even for the same type of transistor. Even so, indeed the circuit is pretty much foolproof.

Had to restart a few times to get the size right, but it worked out pretty well in the end :-D