Electronics

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.

I got my hands on some really weird EL panels and did a little dive into how they work. I still have no idea where to get more but I think they may be DIY-able.

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.

This decade old electric cooler box gave up the ghost around 2 years ago, with the indoor outlet plug no longer working. The independent 12v input was still operational, so I kept it with the intention of eventually fixing it...

And two years later, this is the eventually 😅. The integrated 10v ~45w unit had failed short on the primary side, with a burnt out Y-capacitor and some fried zeners. I started removing bits from the board to try and find all the broken components... but ended up letting out the magic smoke in the process, oops!

I set out looking for a new power supply, and came across a 12v 45w unit from Meanwell. It was actually smaller than the cooler's original power supply too, meaning more internal space to use later 🤫

After searching for a distributor that was actually willing to ship it to a home address, I ordered, and boom:

It's so tiny compared to the original.

Next I installed an Arduino Nano to control the TEC/peltier module & fan via a cheap LED repeater. I was hoping to reuse the internal temperature sensors, but left them disconnected for now

After hours writing the arduino code, I finally got it into a usable state. There were issues with brownouts rebooting the Arduino, however with the Meanwell supply in-circuit those mysteriously stopped.

There are 3 power modes now for the module: 30W, 40W and 50W - with the first two using PWM, and the last one giving it all the beans. I wanted to PWM control the fan too, but decided against it since it sounded absolutely terrible at whatever PWM frequency the Nano is using.

It powers on to 40W by default, which is under the 45W max rating of the PSU.

Everything looks good so far running from the bench supply:

Now all that was left was to connect the internal supply, and the 12v vehicle input. I was actually supposed to use JST connectors for the Meanwell psu, but didn't have anything on hand - so improvised with crimping spade terminals and friction fitting those on

And the moment of truth. Up until this point I hadn't actually checked if the replacement psu was working or not

Looking good! I don't really like the LEDs though, so might do something about those in future.

You might be wondering how exactly I change the power settings... well since the manufacturer decided it was good enough to shove all the cables in the back, I did the same with a pushbutton 🤫

Glad to have the electric cooler working again though, feels nice to save large things like this from going to the landfill and extend their life a bit. Excited to hear any thoughts and feedback!