Electronics

You can do all sorts of nifty things when you're designing silicon. Including this abomination.

https://en.wikipedia.org/wiki/Carcinisation

Source: datasheet for LM161, a high speed (20ns delay) moderately high voltage (30V) comparator. I'm going to try and make a discrete version of some bits of it and see how well it works. Maybe not this triple-emitter NPN though, I draw the line at components that require livestock sacrifices.

FR2 is the brownish material that many cheap circuit boards are made of. It's a mixture of phenolic resin and paper. Apparently it's quite useful to make gears out of:

Phenolic Gears exhibits superior shear force, help reduce machinery noise, absorbs destructive vibration unlike metal gears, phenolic is non-conductive, protects the mating metal gear train, and are known to outlast metal gears under severe continuous service. (source: https://www.knowbirs.com/phenolic-gears )

(Main pic stolen from here)

(Many more pics here)

Has anyone seen these used anywhere? I've read a hint regarding pool equipment, but I have never seen them there. I assume the fibres allow them to last longer than plastic/resin only gears.

Two different sizes shown. Each has two inductors (grey bits) stuck to a capacitor (middle) with some metal end caps acting as terminals. There is a third terminal underneath the capacitor. Grid in background is 1mm, pics stolen from LCSC.

I think this taped picture is also really cool (stolen from here):

Datasheet: https://www.murata.com/en-global/products/productdata/8796766699550/ENFE0002.pdf

This is UV sensitive solder mask resin, applied as thin as possible using a silk screen mesh. Afterwards it's heated at about 90C for 10 minutes. This makes it more sensitive to UV light by evaporating most of the solvent.

It is exposed with a 405nm laser at about 250mw of power. I intentionally unfocused the laser for a spot size of about 0.5nm

After exposure the pads are easily cleaned off with some IPA.

der8auer got the original 5090 card from the reddit melting cable post, then demonstrated that two of the six 12V power connector cables are having 20ish amps running through them and overheating, while the other 4 cables are not.

The thickness of the board beneath it gives deceptive scale. It's about 50mm tall and the toroid is 85mm in diameter.

https://www.lcsc.com/datasheet/lcsc_datasheet_2408061709_Ruishen-RSCM11548-5mH-3P_C37634003.pdf

I was looking for much smaller CMCs. Also the datasheet for this part doesn't have impedance-versus-frequency graphs so I refuse to buy it anyway :P

A open source home automation mobile robot arm!

Exploiting the promise of recent advances in imitation learning for mobile manipulation will require the collection of large numbers of human-guided demonstrations. This paper proposes an open-source design for an inexpensive, robust, and flexible mobile manipulator that can support arbitrary arms, enabling a wide range of real-world household mobile manipulation tasks. Crucially, our design uses powered casters to enable the mobile base to be fully holonomic, able to control all planar degrees of freedom independently and simultaneously. This feature makes the base more maneuverable and simplifies many mobile manipulation tasks, eliminating the kinematic constraints that create complex and time-consuming motions in nonholonomic bases. We equip our robot with an intuitive mobile phone teleoperation interface to enable easy data acquisition for imitation learning. In our experiments, we use this interface to collect data and show that the resulting learned policies can successfully perform a variety of common household mobile manipulation tasks.

Hello everyone, I recently built a small distribution board to distribute 5V to multiple components for use in a robotics project. I made each output switchable with an individual switch and an LED to indicate the current state. When I went to test it using a lab power supply I noticed that the LEDs would start flickering weirdly when I turned them off and on again.

https://imgur.com/a/zaSCUby

As it turns out, the LEDs, which I found in my dads old parts in a bag labeled TLBO 5410, are apparently blinking LEDs. I found a datasheet for TLBR5410 LEDs which seem pretty much identical to what I have accidentally used.

Apparently these LEDs are made to operate directly from a 5V supply without an additional current limiting resistor (it is already built in) and are made to continuously blink at a frequency of 3Hz.

Because I thought I was using standard LEDs I added a series resistor causing them to behave weirdly due to low voltage. For comparison, this is how they are supposed to act: https://imgur.com/a/fXlcEDs

Me a few days ago, shopping on Amazon: "All the component and jumper wire leads are going to be on the bottom anyway; why shouldn't I get a pack of single-sided breadboards for $6.25 instead of double-sided ones for $10?"

Me today, after having lifted three pads off the damn board in 10 minutes: "Oh, that's why."

Get the double-sided breadboards; they're worth it.

4 bit adder. Took me a few evenings this week to put together. Im quite happy that it worked first try without any bugs. Constructive criticism is encouraged.

Im just getting back into building circuits on my breadboard and I want to know if there are any tips from the pros on here to help me on my journey. Also some links to resources for projects would be nice.

Cheap Chinese devices have iron instead of copper in wires. Aluminium is not suitable, since you can't solder it, otherwise I'm sure they'd use that as well.

Don't be fooled if the strands are copper colored, that could be either varnish or a thin layer of electroplated copper. A magnet test will reveal the truth. If it can't be soldered, it's most probably Aluminum. I've seen that as well, but only on wires that use some sort of a clamp-on connector at both ends... basically, it was never meant to be soldered.

i couldn't upload a video so it's a link

This was my first try developing my own pcb with the toner transfer method. I did this project many years back but it works perfectly to this day.

It filters an audio signal and drives led strips so they pulsate to the beat of a song.

We maintain a small fleet of RTK GPS systems (Emlid Reach RS+ units or similar). But sometimes they sit too long on the shelf and parasitic drain kicks in. The manufacturer recommends recharging every three months, but ooops, this one went too long. If the batteries are too low, the battery management system (BMS) won't charge the batteries at all when you attach the USB charger cable. In this case, the batteries were testing at 0.9V rather than the desired 3.4V.

Solution: open the device, expose a tiny bit of conductor on the battery harness, and attach 3V worth of alkaline batteries for a short period. Once the lithium batteries are up a little, you can then charge with the normal USB charger again.

The manufacturer does not recommend opening the sealed unit, as it voids the IP67 rating. And this is not a best practice. But it works. The above photos were taken in April and the unit has been trucking along ever since. Saved a few thousand dollars :)

Instrument is a Geonics EM16 VLF receiver, using in the mineral exploration industry to find buried linear conductors.

Built out my ploopy mouse today, it's been sitting on my shelf for a while. I got the self-assembly kit, had to solder on one through hole component.

So far I'm enjoying the mouse, the right mouse button is a little sticky, but I'm sure with a little readjustment it'll fall into place.

Every part of this mouse is open source, the hardware files, the PCB, the schematic, the firmware which is QMK. There's a lot to love here.

I've been playing some video games, and so far I enjoy the mouse quite a bit.

If I do have one complaint it would be the central scroll wheel doesn't have a detent, but that might just take some getting used to

I would love to see a kinesis style pinch mouse like the DXT2.

@pronk@mastodon.social @PKL@mastodon.social Great device, thank you for making it open source.

Note: I ordered their USB cables, just for solidarity, and assuming they found a cable that was very effective for a mouse, the cables I received were very strong, too stiff really to be used for a mouse cable. Luckily I had some very flexible braided USB cables already. So if you're going to order from them do not order the USB cable

A banger video about applying sintered traces to 3d printed models... BUT more interesting then that is the use of ChatGPT to "exfiltrate" unpublished formulas for the cooper plating solution.

In the video at 8:10 Ben goes through his exhaustive search of trying to make a solution that would work, and details that all the labs keep it more or less a secret, but the application of a LLM revealed the difficult to find steps/formula needed.

Obviously ChatGPT gobbled this up somewhere... just published on the internet but Ben didn't find it? Or did ChatGPT get trained on internal/corporate documents and the LLM is actually democratizing this information?

I'm nowhereman from Belgium. Thanks for accepting me! Just started with electronics. Messing around a bit with motherboards. My 'new' secondhand motherboard got hit by the ground a think whilst in transport. And when I plugged it in some chips burned. The board didn't look like it would do that. Only the corner was hit so I thought it would be fine. I was wrong. But, because of that I wanted to learn about what went wrong.

I got a Sylvania-branded strand of 50 "warm-white" LEDs (plus two loose spares) for USD 2.50 at the local grocery store, which I'm pretty sure is cheaper than buying a bag of the bare LEDs would run. They also come in other colours (blue, cool-white, bright red, multicolour)

The individual LEDs come in plastic shells which can be cracked open to retrieve the goodies inside, and have plenty long leads that are folded over to fit the "bulb" mounting.