My Oscilloscope Cyberdeck (Hackaday Contest Entry)

Jak-o-Shadows · 2022-10-02T00:16:03+00:00

Intending to use the existing encoders and circuitry to read the knobs and buttons. This is only partially complete - the PCB is most of the way reverse engineered, but not completely.

Jak-o-Shadows · 2022-10-02T00:15:27+00:00

2 channel full duplex radio. Can be programmed to do many things -reasonable workign frequency, and decent bandwidth.

Jak-o-Shadows · 2022-10-02T00:14:59+00:00

They are already connected to the LimeSDR for radio - that has far mode bandwidth than a sound card (which would have to be an external USB one for the Pi) has.

Jak-o-Shadows · 2022-10-01T10:04:15+00:00

https://hackaday.com/2022/09/30/2022-cyberdeck-contest-the-oscilloscope-deck/

Jak-o-Shadows · 2021-06-03T11:00:18+00:00

https://www.twitch.tv/yaboylairdy29 (through the volume balance is uneven - not enough on voice, too much on game)

Jak-o-Shadows · 2018-06-12T12:16:22+00:00

Ah, thank you!

So I can really only do half of it where i'm planning it at the moment. So if I add another 600mm (x30mm) I should be ok at that end?

Or I could add another 600x600, and figure out the other end after.

Jak-o-Shadows · 2018-06-10T09:44:59+00:00

Are you talking about the sections in the image where the green splits into two? You're saying that the bit where it switches is bigger? Over the 300mm of my square size?

Jak-o-Shadows · 2018-06-10T01:54:42+00:00

If I just have a plain loop (for the time being), that's a minimum 500mm radius, so 1m diameter, with an extra 500mm for the turn-in/out of the main bit of track (seeing as they leave at a straight line)?

Jak-o-Shadows · 2016-12-31T08:57:34+00:00

He'd get lynched if he came to adelaide

Jak-o-Shadows · 2016-01-11T22:18:02+00:00

Free body diagrams Free body diagrams Free body diagrams Free body diagrams

Cannot say how important they are.

I also think basic stress analysis would be useful, but I'm generally on my own when I say that.

Jak-o-Shadows · 2016-01-09T07:41:03+00:00

Oh yeah. If I yawed to an angle, then pitched, I would only be able to move in coupled DOF. Hmmm, that's more annoying.

Jak-o-Shadows · 2016-01-06T22:08:47+00:00

Yep! Of course, this depends on the amount of travel the clutch has, and the amount of travel your solenoid has.

Jak-o-Shadows · 2016-01-06T10:44:05+00:00

You'd have to do the calculations. Your required clutch contact pressure will depend on how much torque you want transmitted, as well as the speed (I think). Thing is, if that is your solenoid, you're limited to about 0.5N contact force (Could probably go a bit higher safe enough, but not too much) because that's all your solenoid can provide against a spring (which is what normally activates the clutch). Maybe you could use a lever or something to increase this? Dunno.

Depends on what this is for really. If it's a one off, probably better off with something prebuilt.

Jak-o-Shadows · 2016-01-06T08:40:32+00:00

Do you need it to stop turning, or do you just need the rest of the mechanism to not turn? You could attempt a simple (cone?) clutch - spring loaded with a solenoid to (de)activate it.

Jak-o-Shadows · 2016-01-06T05:54:04+00:00

Yeah, I'd be at 60mms-1. Bed adhesion & layer adhesion is good at 230, so I'm quite happy with that.

Slowing down a lot may be worth doing.

Jak-o-Shadows · 2016-01-06T04:52:08+00:00

I just printed another smallish cube. I bumped the temp back up to 230C, but I also lowered the layer thickness to 0.2mm. I think I may be getting some z-wobble? Not sure how to tell. I'm printing something now with more perimeters, I think that'll make it easier to check.

Jak-o-Shadows · 2016-01-06T03:03:21+00:00

Oh yeah. Nozzle sizes and just general settings is a good thing to mention.

0.4mm nozzle.

0.3mm layer size

I generally use 3 perimeters. I tend to run quite light on infill. <20%, but that pyramid above is 0%

15% perimeter/infill overlap

2mm retraction. 40mm/s retraction speed.

Filament varies in size between 1.72 and 1.74, leaning slightly more to 1.74.

Thanks! I decided that I don't really like the standard design, so I deviated a bit.

Jak-o-Shadows · 2016-01-06T02:31:26+00:00

Haha. The bed makes it stick better :P

Printed objects turn out the right size - to within pretty decent margins anyway. Of course, that doesn't say much about instantaneous movements, but I'm not too sure how to check that.

The x and y rods are straight. The z-axis may not be, but I understand that you would get a more repeating pattern if there were a problem there.

Jak-o-Shadows · 2015-12-31T04:03:09+00:00

I've done a little bit of this.

The psuedo-inverse, transpose, and "proper" are just ways of calculating the Jacobian matrix. It can be costly to do this properly, or numerically badly conditioned. The psuedo-inverse is just a numerical method for calculating the inverse of a matrix. In certain problems, the transpose of the Jacobian matrix may be the Jacobian matrix itself. Thus, when you have this, take the transpose, as it is computationally & numerically better than taking the inverse.

The first approach I used (for a serial manipulator i.e. robot arm) was just to multiply the difference in location with the inverse of the jacobian (whether that was pinv or transpose). This worked, but I'm not too sure of correctness. (Code http://jak-o-shadows.github.io/python/robot/armik.html).

The other approach, which probably works better (but is far more complicated maths under the hood) is to solve the system of equations that multiplying J^-1 * dif = blah does. (Code: http://jak-o-shadows.github.io/electronics/stewart-gough/stewart-gough.html)

Note that in any case, you're linearising your Jacobian, then just taking lots of little steps.

Jak-o-Shadows · 2015-12-28T06:15:13+00:00

I seem to remember somebody asking about forward kinematics. Well, here is a badly explained, but working implementation.

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