Spintronics Community Forum

What new part(s) would you like the most?

that would be neat even if it was only avaliable in the simulator. would love to observe the effects inductive and cappasitive reactance.

1 Like

I was thinking about a AC source to mimic the power outlets in your home. It would help for educational reasons to show the differences between batteries and power outlets.
Act 2 seems to make a lot of oscillators, so I think it makes sense to continue with those. Not sure what the possibilities would be.

thoe that would be cool. I dont think it will be possibe using the curent 6 v power suply.
it would probably have to be battery powered or gravity driven similar to a grandfather clock.

if internal friction of the gears(resistance) is ignored their is power requierment to maintain the ocsilation. For simplicity this is called leakage current .
Look up transformer equivlent circuits. this should give you an idea and a good chalange to try to make a work around.

a Power factor corection method would be needed as one way to reduce the effects of the inductive load. both to save as much of the stored energey as posible and to keep the system mooving smoothly.

mechanical engineering wasnt my field of study, so im not even sure if or how to mesure the extent of or how to wrap my head around anular velocity lagging behind positive force in a mechanical system. My best guess would be significant stress on the internal gears of the power suply therby causing even more resistance.

any attemp to correct for power factor would likley negate its intended purpose as well bing that the junctions will face the same effect.

Having gotten into the later part of Act 2, I’d like an AC power source too! It could be done simply (famous last words) by adapting a reciprocating gear mechanism to drive a sprocket a fixed distance (Spin watt?) clockwise, then counterclockwise. Come to think of it, with a cam-and-follower, it could even be a kind of fixed function generator…

EDIT: The mechanism in that video would produce a triangle wave AC generator. A scotch yoke would produce a more sinusoidal waveform, with the benefit of controlled amplitude.

I had an idea for a very simple part, to solve a very annoying problem- getting belt tension just right. I’m looking to 3d print a prototype for my own use, but haven’t made a model for it yet- the “Belt Tensioner”. Effectively the same as a 0-Ohm resistor or the level changer in the simulator, but instead of being fixed to the magnetic base like all the current components, it’s on an arm that can be “extended”. This would allow it to be adjusted a bit more carefully than nudging a closed switch or similar.

You mean a derailleur?

Essentially, but without the sprocket changing. (though, I wonder what creative uses being able to dynamically change levels would bring…)

So like this chain tensioning module on this single-speed bicycle.
(picture is public domain from wikipedia)

It might take a little work, but a spin oscilloscope would be helpful. My daughter and I just received our spintronics lastnight and we made a rectifier. Tonight we added a filter to smooth the output. I suspect it wouldn’t be too difficult to create, perhaps a drum based 'scope using a felt marker on paper. The drum would spin based on a clockwork, perhaps the spintronic’s power supply, appropriately regulated, and the deflection would of course be based on the spin voltage. Would make the half, full wave rectification, as well as filter tuning all the more tangible. Congratulations for bringing such a complex idea successfully to market! I am envious of the generations of kids who will build profound intuition having experienced your models. Thank you!

1 Like

How about an equivalent to an LED that raises an indicator while current is flowing and drops the indicator when current stops?


I realize this might go against the “all mechanical” philosophy of Spintronics (which I do think is awesome), but I found myself wanting a “battery” that was actually electrically powered (preferably plugged into the wall, rather than running on “battery batteries”), so I could leave a circuit running as an interesting piece of office art. Maybe there are also non-philosophical reasons why this would be a headache (perhaps a risk of mechanical damage while running unattended?), but I thought I might as well make the request.

I’ll second the request for some sort of paper plotter to show voltage and/or current over time!

Of the pieces I’ve worked with the ampèremeter is my least favourite. The idea of a grammophone is nice. But the sound is annoying, the difference in sound is different to hear and it’s not quantitative like the voltagemeter.

My idea is to measure the rotational speed by placing a bowl with a marble on top of the gears. The rotation is pushing the marble outward and gravity pushes it down. By giving the bowl a curve, you create an equilibrum position for a given speed. By printing lines on the inside you can measure speed quantitatively.

Now, I don’t know what dimensions this bowl/whirlpool will become, but it’s an idea to explore. Maybe the lane in which the marble can roll will need to be fixed.


Couldn’t help thinking about this a bit more, and have a few more suggestions…

First, some fairly straightforward mechanical ones that are still worth mentioning:

  • A dedicated level changer, like the one in the simulator
  • A push button, i.e. is on only while it is pressed (useful for any circuit with latch/reset behavior)
  • I only just got my head around the three-way junction, so I don’t know what’s possible here, never mind practical, but a four- or five-way junction seems like it could declutter some circuits (presumably with some gears sharing levels)
  • Something like a (resettable) analog odometer, which could measure total charge flowing through a part of the circuit (I don’t know if it would be practical to measure the total energy by also detecting the voltage); bonus points for making it look like a part of Babbage’s Difference Engine
  • Mechanical counter that detects number of pulses (same bonus; more appropriate here, really)

Next, a few electrical/electronic components I haven’t seen mentioned:

  • A Zener diode, i.e. current starts to flow past a certain voltage (may or may not be a diode in the other direction – perhaps the Spintronics version has the “breakdown” behavior in both directions?)
  • A transformer that allows winding/gear ratios other than 2 or ½
  • A large capacitor that can actually store a decent amount of the battery’s input energy (not entirely sure this is useful, but maybe it’s more practical in some circuits than “leaving the energy in the battery for later use”)

Third, sensors. Light and sound sensors are clearly impractical unless you involve electronics (um, see below). An accelerometer might be practical, but this would presumably require something like the aforementioned “steampunk chassis” in order to be useful. That leaves:

  • A pressure sensor – could even be used to build a simple scale?
  • Temperature sensor – probably much harder to build reliably, but it would be cool to see a bimetallic strip incorporated somewhere

Finally, since I “went there” with the plug-in battery (or “electrical/mechanical energy converter”) suggestion:

  • A “smart block” with a tiny screen and simple programmable microcontroller. Would presumably draw power from the plug-in battery. Obviously extends Spintronics in a fairly radical direction, but I do think it’s interesting to demonstrate conversion between different kinds of logic. There are a lot of toys in this space, but maybe this smart block could be compatible with some of them, in which case the toys could then be used together (and alternately, maybe the “smart” block doesn’t actually need to be smart or have a screen, just interface to something that does).

The parallel magnetic planes solution to the variable resistor sounds great. There’s so much you can do with that trick. I hope @pgboswell tries this out.

The only current form of input is the switch. I don’t know if it is possible but a potentiometer would be very nice to have.

I’d request the variable resistor utilize some method that isn’t just mechanical friction-based. The reason why is that mechanical friction-based methods typically require higher precision positioning, which isn’t something plastic is good at doing reliably. I struggled getting the constant current source working well on an actual set (and never really did, and verified it matched the solution and that the chains had slack in them) I believe because it relies on the active region on the transistor, which is basically a mechanical friction-based variable resistor.

A couple thoughts would be to have multiple different sized rotary dashpots/dampers (which use viscous friction like the current resistors) that can be selected between with a knob. This might only allow for a few resistances, but some could be combined (think like binary to make numbers). There might already be something out there that allows for adjusting the damping of a rotary dashpot. If not, I imagine you could have a knob or something adjust an aperture between fluid chambers or something. This would work well for a linear dashpot, but not sure how it could be applied to a continuously rotating rotary dashpot. Sealing might be a challenge though.

Another idea that’s based on the force between two disks idea would be to have a continuously variable transmission that is coupled to a fixed resistor.

thank you for this beautiful set. We played with Christmas. I would like to support the idea of ​​the reversed diode with some points. In addition to preserving the extra parts to put the diode on the outside of the chain, centering the diode by putting it inside makes it possible to ensure the tensions of the chains according to the axes. And I add another argument is that it is easier at the beginning to explain the concepts to keep things simple and symmetrical to make education. If you added to the list of items at the store, a set of two reversed diodes, I promise you I will take one.

Parts I would like. Not all of these might be feasible or realistic.

  • an electronic battery unit. This would let me have a circuit set up on my desk to demonstrate to other people, or to just watch myself
  • an AC battery, this has been discussed by others here too
  • reverse diodes
  • variable resistor/potentiometer
  • a better transistor with a more even resistance in the active region. I don’t know how this would be possible, but it would improve amplifier circuits.
  • a quantified current output

I have been working through acts 1 and 2, and have loved it.

Human-powered generator;
We can experience the resistance value, load fluctuation, etc. by turning it by hand.

Used as wind sensor, wind power generation, fan.

Music box;
As rotation speed application.

Tension indicator chain;
Built spring etc. into the chain, as a substitute for voltmeter.

After playing for a while (I only finished act one and just started act two), there are a few parts that would make some things more convenient.

-dedicated level changer (doesn’t have to be 5-level like in the simulator, just 3-level would do). I know switches can do it, but a dedicated one would be more clear, looks like a simple component to make, and would leave the switches available for actual switching

-a component with 3 gears of different size that are connected together (so like the junction, but all gears fixed, so like a level changer with differently sized gears, big at bottom, regular size middle, small at top). This would make it much easier to make transformers (because making perfectly corresponding matching chains for the two-chain setup is somewhat hard). It’s also possible to simply have a way to “fixate” the junction (connect its 3 gears together, can be done now already with a paperclip through the decorative holes of the largest and middle gear), then this component is re-usable for this purpose.

-a hand-crank as input, as an alternative to the battery: then you can crank at any speed and direction you want, even emulate AC

-something that rotates like a windmill or similar (e.g. looking like the inductor but without weight), as an alternative output to the ammeter: the ammeter is cool but as said by others the sound is not always pleasant, an alternative would be great. It may also be possible to have handcrank and this output be the same component (though self-rotating crank may be a bit ugly as output), then you could make a circuit where you can choose which side is the input and output (e.g. test transformer both ways with your hands)

-diode that spins in the opposite direction (or a single one but with a magnetic foot on both sides so you can put it upside down): I know you can get opposite direction based on how you position it next to chain, but it would still make some experiments more convenient

-odometer, so you can e.g. verify that one part rotates 3x as fast as another by having an odometer for each and comparing numbers

-some chain pieces of yet other colors than blue and black, a sprinkle of various colors of them so you can use red, green, yellow, … to mark your chains as having various lengths (e.g. give pairs that work for transformer the same color, …)

-this is not really a new part, but some way to gracefully discharge the battery (with e.g. a button on it) even though it’s connected to circuits with multiple chains that are currently hard to remove, would be nice

-this is also not really a new part, but, make use of the diode in act 2: I’m only at the start of it but took a glance through the book, and I see the transistor+junction combination that act as diode in several circuits. I don’t know yet but I think they may have the same slight difficulty where you must have perfectly matched chain sizes to use it, while the dedicated diode works so well and has such satisfying sound!