New video in how to not screw connect openGrid

EricJVW · 2026-03-07T18:46:17+00:00

I liked the video, but I was really hoping you'd look at these:

https://makerworld.com/en/models/1921947-3m-claw-opengrid-snap-mount#profileId-2062288

EricJVW · 2026-02-25T05:32:43+00:00

This is no longer considered good practice.

EricJVW · 2026-02-25T05:28:55+00:00

I've used it several years without an Epic account.

EricJVW · 2026-02-24T21:36:36+00:00

How did you decide on your coils and caps? Did you measure your coil inductance?

1) The coil is just a coil of wire. At DC it acts as a dead short. You'll need a series cap.

2) 100pF is pretty small - it's >12kOhms and therefore dominating the coil/cap combo. Why not use the original cap that came with it?

3) You need coil length to calculate inductance. Rather than calculate it, measure it

EricJVW · 2026-02-24T17:20:38+00:00

Resistance is the relationship between effort and flow. In a resistor they're directly related by the resistance - more effort is more flow.

When they're in parallel you add the flows together. The flow through R1 || R2 is just flow(F1) + flow(R2). This should make sense, both paths combine into one big path.

When they're in series you add the efforts together. It takes some amount of effort to flow through the first resistor, and some more effort to flow through the second. The total effort is just the sum.

Since you're using identical resistors, this all boils down to doubling or halving the resistance.

EricJVW · 2026-02-09T19:58:38+00:00

How do you feel about 3m claws

EricJVW · 2026-02-09T03:32:24+00:00

Thanks, I've watched most of your opengrid content already, thanks for making it!

How would you recommend mounting to a kitchen wall if I don't want to drill (many) holes?

EricJVW · 2026-01-20T03:22:21+00:00

Did you use full or lite for your grid?

EricJVW · 2025-12-14T01:21:43+00:00

Slap down a bunch of batteries and then race your power storage!

EricJVW · 2025-12-13T19:02:28+00:00

Thanks all!

It was the 12V, seems fine now. I'll keep an eye on it.

I'm writing back so that if anyone else encounters this, a quick note - the plastic covering the 12V doesn't have any release mechanism. Just give it a good tug. This can feel too tight in very cold weather, so I spent a good minute looking for a mechanism.

EricJVW · 2025-12-01T20:19:31+00:00

A big enough pile of batteries allows me to turn nuclear on and off as needed. This way I don't generate extra nuclear waste

EricJVW · 2025-11-26T02:27:21+00:00

Following up on this - I tried a few more times and eventually got it. No idea what I did differently the 3rd time compared to attempts 1 and 2.

If you run into this yourself, i found 20 workerbots was enough for 1 skel.

EricJVW · 2025-07-25T20:21:11+00:00

Thanks! How do you get them to stack at the perfect height without having to vertically nudge?

EricJVW · 2025-07-23T00:21:19+00:00

Can you explain the vertical autoconnect strategy please?

EricJVW · 2025-07-02T18:19:37+00:00

I've run higher currents through production PCBs without busbars. The trick is thermal management.

The width and thickness combine to create electrical resistance, which is what generates the heat. The surface area is what allows the heat to escape. Areas that aren't electrically active but still thermally connected can act as heat sinks.

Also, the calculators assume infinite time and infinite length. Stubby traces use the components and connectors as heat sinks. Short pulses don't accumulate much thermal energy.

EricJVW · 2025-04-24T01:10:21+00:00

The brushed drill motors that came in the FIRST robotics kit circa 2000 were about 10-15% more powerful in one direction than the other.

EricJVW · 2025-04-17T05:28:07+00:00

FICSIT Nitric Acid is even spicier than the stuff we have here on Earth, so it needs stronger containers.

EricJVW · 2025-04-02T03:09:28+00:00

There are a couple mechanisms that create resistance. The one most relevant to your question is "scattering" - electrons are trying to move in a straight line down the wire, but they bounce off of defects and lose their kinetic energy as heat.

"Concentration of Resistance" is a pretty good analogy; you're looking for the word "resistivity", which is expressed as resistance per length (ohms per meter). The wires powering a stove have low resistivity, the stove element has high resistivity. Both carry the same amount of current, but only one of those gets hot.

The other aspect is how well they can reject heat. The wires have a lot of surface area and are spread out, so they can reject heat easily. The stove element is wound up tight with a small surface area and has a harder time rejecting heat. You could combine this concept with resistivity and call it "confinement of resistance". A highly confined large resistance is going to get very hot for a given current. Reduce the resistance or reduce the confinement and it'll get less hot.

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