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My wife gifted me this super cute mini miffy diorama from a gachapon. It uses two 1,5V cells and has a tiny led in it. I would really love to to add a 24h timer. ( it should stay on for 4 hours after turning it on then go to "standby" for 20h before turning back on) Do you guys think an attiny85 is the right thing for the job? Sorry of the question is dumb in any way. I am absolutely not an electronics guy.

Hi,

I'm looking for some help in a field that is super technical and I don't fully understand.

I'm planning on using a bunch of these seeed studio Esp modules for some home automation projects, especially because they have a lipo battery charger making it great for portable stuff.

The thing is the the ESP32s have U.FL SMD antenna connectors. Most of the antennas that you can buy with U.FL connections while are reasonably small, come with 50-150mm leads, which sort of makes the small size of the module a little less valid.

What I'd like to do is get a female U.FL SMD connector and make a small daugherboard with an 2.4GHz SMD antenna on it, for instance a Janson 2450AT42B100 or a Molex 479480001.

They go over the circuit board requirements quite thoroughly so I don't think designing it will be too difficult, but what I don't know is, they say that you need impedance matching on the circuit, and I see that there appears to be something that looks like it on the ESP circuit diagram, but I'm not actually sure if it is or not:

You can see it in the middle near the bottom of the diagram here: Seeeduino-XIAO-ESP32C3-SCH

So my questions are:

1: Is this a dumb idea, having a direct plug-on SMD antenna?

2: Is that an impedance matchning circuit between LNA_IN on the ESP chip and U.FL-R-SMT-1?

3: If I can't get a female U.FL SMD connector, would using one with a lead and shortening it to make the daughterboard able to be much closer to the connector affect anything? Do I need to ensure that the lead length matches the wavelength at all?

Edit: Found this SMD female U.FL, so they do exist.

I got my hands on an old e-ink price tag and want to repurpose this display.

Unfortunately, I can't really figure out, what this type of connector/bus is called. To me it looks like a standard issue ribbon cable.

There are some "universal" e-paper drivers (for example this one: https://www.ebay.de/itm/353141399922), but I have absolutely no idea, how to find out, if that's the right connector.

The device is made by Imagotag, if that helps.

Edit: I added a picture of the panel: https://feddit.de/pictrs/image/42ee4f60-231a-4c42-9a66-6c369134c49c.jpeg

None of the "markings" returned any results and the QR code couldn't be decoded by my phone.

Hi, I am automating my manual switches at home with ESPHome on NodeMCU. For controlling the switches, I am using 8 channel relay module.

The back of the board has solder-points sticking out. I will be installing this relay module inside the switchboard. So I want to put it in some kind of enclosure.

Just wanted to know your thoughts on enclosure. Should I just wrap the whole thing in electrical tape? Or a plastic box maybe?

Hi everyone! Recently I have gotten interested in communication protocols and have been looking for one (with little success, hence my question) which would satisfy the following requirements (in prioritized order):

• All devices should be able to initiate communication (not your typical master slave with polling)

• Devices should be able to address messages directly to one another without a single one permanently taking on some host/master/relay role

• Devices should be hot-pluggable (A new device may be connected to the network or removed from it without problems even when the network is up and running)

• The protocol should be stable and immune enough to noise so that it can be sent through wires up to at least 5 meters, ideally even up to 10-50 meters.

• It should be simple, implementable even on low-perfomance microcontrollers.

• It should have its maximum transfer rate in the kilobytes per second range or preferably even megabytes per second.

I have looked at I2C, which for the most part would be fine, but as far as I understand it was not meant to be sent through a wire and it would be quite vulnerable to interference. (It also is by default a master-slave protocol, but it also has a multi-master mode, so maybe making every device a slave and a multi-master master at the same time could work?)

The rest of the protocols I looked at were all master-slave, which, for my purpose, is unacceptable.

That being said, I would be grateful if you could give me some pointers as to what protocol may satisfy these requirements and perhaps even on what sort of wires and signals it would require (twisted pairs? Differential signal? Shielded twisted pairs? Could plain simple wire suffice? etc.)

I just came across this and thought I'd share. I've struggled to get headers and IC's off boards after soldering them on backwards/upside down. This video shows a cool trick with a piece of copper wire that makes them very easy and quick to get off without expensive tooling. I was thoroughly impressed. Hope someone else finds this useful too.

I purchased an e-bike which was advertised as just needing the batteries replaced. The li-ion batteries had been sitting dead for months. Once I got the battery removed it was clear that was not the case. You can see the hole where the plastic melted from this component overheating on the board. The burnt one is the same as those in the center of this photo.

What is it and how do I determine the correct replacement?

I replaced my laptop's battery after it was swollen. I found out that services like call2recycle do not take swollen batteries since they are potentially hazardous material. How can I get rid of that damned spicy pillow? In Dallas. Thanks.

Thanks for the suggestion and tips guys. I have bought lipo fire resistant bags for the batteries. As stated in suggestions here, most of the places like Home Depot, Best Buy, Lowes do have a recycling program; but some of them have disclaimers regarding not accepting swollen batteries. I plan to go to Batteries and Bulbs, Best Buy asap; they look most promising.

Trying to identify a component on a pool control board.

It's related to the T-Cell functionality of the board, since everything else like sensing, timing, and whatever else works on the board.

Component got water on it, most likely when a not uncommon occurrence of water jetting out from the filter and splashing onto the board eventually got where it shouldn't.

@askelectronics

Hey all, have I damaged this xbox 360 controller circuit board beyond repair?

The Pictures

https://imgur.com/a/oum8Yg4

• The Red circle is the side I managed to fix.
• The Blue circle is the parts I could not get to bind properly.

The issues and my process

So I had a pair of xbox 360 controller controllers with corroded battery terminal springs. I managed to successfully replace the first controller's springs, but the second I was having trouble with. The solder would not bind to the pad and it would form a lump that would break off under any pressure.

I consulted the internet and someone mentioned I just needed to crank up the heat. That didn't work and the binding seemed to get worse, further it looks like it is now burnt all the terminal pad.

The internet then told me to scrap away the surface as it might be residual flux and it should be fine underneath. It still fails to securely bind.

I suspect the corrosion ate so far into the device that the pad itself was too weak to bind. I also suspect I am an idiot.

Is there any saving this?

My Plan should I discover I borked it

360 controllers have additional terminals on the back which I might be able to connect to something instead of the battery pads.

Hey everyone,

I'm a complete beginner in the world of soldering, and I'm facing some frustrating issues with my soldering iron tips. After just a few minutes of use, my soldering iron tips can't melt the solder anymore.

I always keep a sponge nearby and make sure to clean the tip frequently, just like I saw in tutorials. However, the tips still look a little "burned"/ black. Am I doing something wrong? Or could it be related to the soldering equipment I'm using? I bought a $20 kit on Amazon just to practice.

I'm trying to use an LIS2MDL ic with an Arduino nano on a custom PCB designed in KiCad. I tried the Arduino example compass script for the ic and it didn't work. It just prints "Magnetometer Test" and nothing else happens

//Edit: It's a SAS drive. thanks for the help :))

I bought two of these a long time ago, and I recently tried to connect them to a SATA III connector without luck. The size seems to match up, but the block between the two pin segments seems to block it from connecting with SATA III.

Can you help me figure out what kind of adaptor I need ? :))

Hello, I have a circuit that will need to return connected hardware to a default state if power is lost. The hardware can handle continuous voltage, so I'm thinking a simple solution would be to use a battery to provide that fallback power source. To avoid draining the battery, I'd like to connect it through a relay on the normally open contact and energize the relay directly from the main power supply on my board.

Do I need to look for anything in particular to make sure the coil on the relay I choose can sustain constant voltage for potentially months at a time without damage? Or, is there another similarly low cost and simple solution you'd recommend?

The circuit runs on 12VDC from a [Mean Well IRM-10-12 (specification), and the relays I have on hand are OMRON G5LE-14-CF 12VDC (specification). I don't see anything on the relay documentation that specifies a maximum duty cycle.

I'm curious and am playing around with a new EDA tool and am looking at practicing by designing a PCB which should be roughly 28x26mm footprint (give or take a few mm...).

It should be an LTE cat 4 device, connected by USB type C for the framework laptop and is unlikely to include antennas.

Where I struggle is identifying potential modems to use. The only one even remotely close is the u-blox LARA-L6, which is 24x26mm. What alternatives are there?

I am trying to see what gets sold in these USB dongles but there is little info. The few I have identified seem to make use of the Qualcomm 9207, but its's unclear to me if its a ready chip (which is what the MDM9207 is?) Or if it is an IP core to integrate in one's own chip?

A video I came across seem to indicate it (the MDM version) is tiny:

https://www.youtube.com/watch?v=ToCyUCIoXEM at 2:13

But will probably needadditional things to be integrated and I created an account at Qualcomm but they won't give anything unless I'm certified from a company to be a customer and actually integrate it...

I have a whole bunch of them. They are possibly a bit older (70s, 80s) judging by other contents of the junk box they are from.

There are no labels of any kind, but on the top they have stripes that look hand painted.

For at least some of them the resistance roughly corresponds to the color code.

So, I'm just curious why I can't find anything about these on the internet.

As the title says, I'm looking for a Linux/macOS-compatible EPROM programmer. I'd like to be able to program parallel (E)EPROMs in the 27xxx range. The newer XGecu programmers seem to not be compatible with Linux/macOS, and the selection of TL866(II) clones is too overwhelming for me to be able to choose one.

Any suggestions?

This photo shows the power conversion side of two versions of the same board. Input is up to 60V DC, board converts to 5V and then down to 3.3V.

The top board works correctly all the time. But the bottom board has strange issues. Everything works perfectly when I connect it to my bench power supply at 53V. The board powers up with no problems. When I connect it to the daisy chain of other boards, it suddenly will no longer power on, despite ~54V being passed through correctly to downstream boards.

This is a real head-scratcher for me, and I'm having trouble making sense of it. I'm not so much looking for The Solution as to what steps I should take to troubleshoot this. There were some issues attaching the image, so in case it doesn't show up.

https://photos.app.goo.gl/MCx7Q4BDbKTv68EJ8

Circuit is for controlling the fan on a Raspberry Pi, just on/off according to temp, no PWM. Not sure about the diode as it has a .7V drop and it's a tiny brushless DC motor. No markings on the fan so I measured the current with a multimeter when hooking it up to a USB charger. Circuit was adapted from here using what I have on hand.

Suggestions? Any advice is greatly appreciated!

*EDIT: Confirmed, this circuit works on a Raspberry Pi 4. Base was wired to GPIO 17 and manually tested using commands:

raspi-gpio set 17 op dh

raspi-gpio set 17 op dl

I didn't use a breadboard, just hack-n-slash with the wires coming out of the fan, the leads on the thru hole components, a jumper connected to gpio 17 as a socket for the base/resistor lead, and heat shrink tubing for insulation. Folded it up as I closed the housing. Case combo including heatsinks and fan here.

Do any of you have experienced good products for tinkering together with a 3 year old?

I thought about something like a giant breadboard with simple connectors to switch on a light or play a sound or something.

It doesn't have to be too fancy, just sturdy and safe to play together with an adult.

Thanks!

This is my electromagnet.

Hello there, This oscillator is a 0V +10v DC oscillator, which after current passes through the capacitor, it produces a -5v +5v AC on the resistor.

We've all heard that AC removes DC component and let's AC pass by. I understand the dynamics of this circuit in case the oscillator were operating with AC (capacitive reactance), however this oscillator is DC, the voltage across the capacitor never changes polarity (since the other side of circuit is ground), so what gives? And why the 10V DC is split on half +5 -5 volts after the capacitor? Thank you!

Hi! I'm working on an arduino project that has a -12v/0v/+12 psu. +12 is fed directly into arduinos voltage regulator, so there's also a +5v line available. I need to convert a -5v+5v signal to 0v+5v to feed it into arduinos analogue input and I've already mocked up a schematic in circuitjs based on an opamp that seems to do what I want. The only problem is that it needs -5v to shift the signal to be unipolar. I know that I can invert +5v using another opamp, but maybe there's some simpler way? I'd really like to avoid adding another opamp just for this? In this schematic I used simple voltage divider to get the needed voltage, but I guess that's not the best approach?

TLDR: I have -12v, 0v, +12v and +5v, what's the easiest way to get -5v?

Hi!

I have bought a Geberit shower toilet/bidet with a motion sensor but it's aimed at the front while the toilet is installed sideways. So I've opened the thing up and I can take out the motion sensor, but the cable it's connected to is too short to do anything with. So I'm looking to buy/make an extension cable, but I have no idea on how to find it. So I took pics of the connector and I'm hoping you can help me find the type of connector (and if someone has a buy link: even better!). Thanks!

edit: https://www.jst.com/products/insulation-displacement-connectors-wire-to-board-type/vr-connector/ this looks like the socket, but the pitch seems wrong?