As almost everything was done with electronics,
(v1.2 control circuit PCB's are on their way)
it's time to think about structural questions.

And first one - electromagnets.

If we even can control them efficiently, it doesn't mean, that we solved problem of energy density, which defines how much force we can get from the electromagnet within some weight and size.

There are some things which I discovered recently:

- according to precious Coil64 (big thanx to developers, very useful software), with limited voltage best way to improve pulling force - is to use wire diameter as big as possible, however, too much current would generate big energy loss on semiconductors, so it's a questionable decision. Control circuit has a way to regulate amount of energy being pushed into coil during a cycle, so it might be a solution. Also, smaller capacity on C3 means significant rise of voltage (comparing to a supply voltage)

- cores with great permeability are wild! They can increase inductance (read as "top energy of magnetic field for a specific current") very much. I don't know where to find Metglas cores with needed dimensions, seems to be impossible now, but I've bought induction heater to produce "very-pure" iron, annealed in hydrogen. Permeability of such iron is very close to Metglas and it's possible to fabricate for yourself (of course - you need to be careful)

Combination of a great core material and control method should do the job, maybe I'll come up with additional ideas about increasing energy density later

A concept how it might look, with coilformers, cores e.t.c ->

Fe cores are grey there, main reason why you can see them - nothing is between coil and core on sides (only electrical insulation), minimizing gap between wires and core is a crucial thing, as it defines inductance pretty much!

Stripes there are glued to the deep-purple parts, their main task is to transfer tension from the stripe to bearing at the back of electromagnet. If you need to swap stripe - then you should unscrew deep-purple parts, electromagnets untouched.

So,
Now I have:
- 2x stripes
- control circuit (previous version)

And one thing I miss to get the thing done - cores. Hopefully, I would find some material for them on Sunday.

P.S. I'm pretty curious about energy dissipation, because I can hardly feel heat from electromagnet with which I tested control circuit previously. It would be quite surprising to find out, what it's not heating at all. Quite strange.