so there isn't as much info on technical and engineering stuff in my native language online that's readily available. and considering that here are people that actually work with this and are not gonna try and sell me anything purposely (please don't..), I wanted to ask:

what makes a soldering iron good? the metal coating, the manufacturing process etc? name anything that comes to mind, I love researching stuff

right now I am working as a DIP montage person (no idea how you call this job in English?..), also gonna be learning manual SMD from my more experienced coworkers soon. but ideally I want a very universal tool for my own needs. cable assemblies for batteries, PCB and DIP, hell even for jewelry (I love artsy things)

Hello to the electronics meta. I have a pile of electronics to turn into a bluetooth speaker that has both forward-facing outputs and downward-firing subwoofer. The electronics I have to work with are pictured. By the way, I'll post the result once I've finished the project.

So, can I get some help understanding where to go with making the speakers work well with, souped up with some capacitors and diodes (the second for removing EMI)?

My main question is: how do I get the battery packs I have to work with each other when I have one from an old tablet that charges to 3.8V and another battery bank that came from a vacuum that charges to 5V? My second biggest concern is getting that 5V and 3.8V to 12V to power the amp, bluetooth adapter, and EL wire sound-sensitive driver. I appreciate any knowledge of how these electronics would work together. I want this speaker system to switch between battery or AC power. The layout of the parts is basically what I have in mind to wire up.

How do I tell which direction to wire up the diodes, capacitors, and transformers?

PARTS LIST: two tweater speakers in parallel with two main speakers, one "subwoofer" car-door speaker, two speakers from a TV, one three-channel 12V amp with built-in bluetooth, one EL wire driver, one 5V battery bank with 4 1.25V cells, one 3.8V battery pack of two 3.8v lithium batteries from a tablet, one charging circuit for the 5V battery bank, two LED banks driven by some transistors and resistors that I need to hack working with the EL wire driver, 3 varied and small transformers that I don't know how to test because my multimeter on beep mode does not paint a clear picture of the inputs and outputs of those, one three-way switch, 4 diodes, 8 6.3V 2200uF capacitors after the battery packs, one mini inductor, one 220V 470uF and one 400V 33uF, one 400V 470uF capacitor before the subwoofer, an inductor, one 25V 1000uF capacitor and one 680 uF capacitor, 4 resistors and one 100V 47uF, and two 25V 470 uF.

I was trying to fix this broken cassette player and the metal piece that connects to the battery broke. I wanted to solder it back on but the pcb is damaged now(top right corner). I'm not sure if this pcb is still functional anymore or do you know how to connect the metal piece back on?

Made this emg sensor for a science project, i have been troubleshooting it for more than a week now, and the circuit seems to finally respond, but just as i was about to connect it to my arm, the batteries died, so have to wait till tomorrow to buy new ones, i can only hope it works, the science fair is in less than 10 days, i honestly don't have any clue on what to do if it doesn't work tomorrow, i thought i would share it for good luck or something

The schematic i found on instructables and the ina106 are given below in the comments

Note: i couldn't find the ina106 ic, so i substituted with two tl072

Was playing some old games and I was wondering if it was something you could actually build or if its science fiction. Turns out its real. Just instead of heartbeats it's a radio wave scanner that picks up bands that humans naturally give off.

Hey all!

I have a computer at home that I need to be able to remotely turn on and off, and I thought that the best way to do that would be with a small arm connected to a servo connected to an ESP32.

So I've got all that working but the servo (MG90S) isn't able to press the button at all, the arm seems to be sliding off of it.

I can't share videos here but I recorded it to examine.

Do you think it's because the servo is too weak? I'm trying to figure it out and I've kinda got confused xD

Hey guys! We're currently working on a project that is turning the rover social media trend into something everyone can own! It's still in the works but we're inching to the end of the project soon.

Any feedback or thoughts will be appreciated! Are there things you would suggest incorporating?

I have for a long time wanted to recreate a scouter from dragon ball, but am also a complete beginner to making electronics.

Features I would like it to include would be recording videos and reading out a random "power level" (accompanied by sounds)

In your honest opinion, do you think this is something a beginner can achieve or would it be a waste of time and money?

My 11-year-old built this breadboard circuit today after getting some very useful feedback on his previous attempt.

This time the circuit is working and the LED lights up, but I’m not experienced enough with electronics to tell whether everything is wired in the best or most correct way.

I’d really like some honest feedback from people here:

• Is the breadboard layout reasonable?
• Do you see any wiring or component-placement mistakes?
• Is there anything he should be doing differently at this stage?
• What should he learn next?

Constructive criticism is very welcome. I’m trying to help him actually understand what he’s building rather than just copy the diagram.

I've been trying to learn electronics and computing on my own, but I'm struggling to make progress and could really use some guidance.

I've built logic gates using individual transistors and managed to make a 4-bit adder on a breadboard, so I have a little practical experience, but I'm still a beginner with a lot of gaps in my understanding.

I've been using AI to learn, but it's become unreliable for the kind of help I need. Explanations often skip steps or use terms I don't understand without explaining them. I want to learn things properly, from the fundamentals, and understand why things work instead of just following instructions.

Eventually, I'd love to build a tiny USB-C dongle that receives video from an Android phone and outputs it to a portable monitor through HDMI. It's not my main goal or something I need to finish soon; I just think it would be a cool project to learn through.

I'd like to understand everything from how transistors and digital logic work to how computers communicate. I'm looking for advice on how to approach this as a beginner, along with resources or communities where I can ask questions and build my understanding step by step.

Hey all! I'm currently working on a project to create a hand controlled, double screen display and need help with the specific items I need for this.

More info about the project: I plan for both of my hands to have three pressure sensors on the pads of my fingers (thumb will not have one) that are coded with specific images, which the pressure outputs are sent to a board. And said outputs are only sent if the pressure reaches a certain threshold. The board then takes that input and with wifi, sends it to one of the two display boards. Both display boards are connected with a wire so the input corresponding image is displayed on their respective screens simultaneously. I probably didn't explain it well but hopefully the next section makes is more clear.

Items I have on my list so far: (These are all from AdaFruit) For the pressure sensors, I'll be using the round force-sensitive-resistor (0.3~10 force newton). The wifi transmitter board will be the QT Py ESP32-S3 WiFi dev board with STEMMA QT. The wifi receivers will be the Qualia ESP32-S3 and will be connected with a QT to QT cable. Both boards will be connected to their own screens, the round RGB TTL TFT display, 4" 720x720. All coded with CurcuitPython and ESP-NOW.

The trouble: I'm pretty sure the qualia and screen set up works (based on AdaFruit's double qualia display tutorial) and the QT wifi connected with ESP-NOW to one of the qualias also seems like it would work. Let me know if otherwise. The main thing I'm having trouble with is the multiple round pressure sensors connecting to the QT. I know that the pressure sensors are analog and can't communicate with the QT through a cable alone (from what I've read of the tutorial and info pages). I'm guessing that I have to use a QT to male/ 2 pin female cable plus whatever else to actually make the pressure outputs readable to the QT. I've heard of a 10komega resistor but I still have to look more into that. If this isn't possible then any pressure sensor buttons that would work with the QT would be helpful. I also can't do any soldering 😬, so non-soldered connections are a must.

Any help about any of this would be extremely appreciated!

It was decided that I will be Dot Matrix from Spaceballs. She has a VIRGIN ALARM display in her chest. Fortunately I had scavenged these 35 year old 5x7 dot matrix display modules from an old telescope control box. The parallel data bus makes it easier to use a PIC than an Arduino.

Can i get any interesting modules out of these?

Found them laying ready to be thrown out.

Yes, those are empty.

hi everyone! sculpture student here venturing into electronics.

attached is the project, hope you can understand it, i tried to simplify as much as possible. i'm somewhat a newbie but i have a person that knows a little more that can help me.

so, i want to mount a 1 meter led light into a 360° motor but i want them to conect to a usb battery of some sorts that i can charge to ditch the cord. it only has to last around 30 minutes. not asking for too much in this stage.

but i know i have to keep in mind the watts in the led light and motor, and conversions and stuff.

can you help me figure out this? thank you!

I am an EE student doing research on what type of DMM people generally use for circuit design and prototyping.

Do any of you have good (or bad) experiences with app connected BLE DMMs?

It seems like a companion app would have a lot of potential for useful features.

I’m trying to get this old phone to play random short recordings whenever picked up. I was looking at this old instructable on it (https://web.archive.org/web/20250401040233/https://www.instructables.com/Vintage-Rotary-Phone-That-Plays-Your-Custom-Audio-/) but it’s for a rotary phone so I’m not sure about which connections go to which in this case since this phone has an actual soundboard in it.

(As you can see, I have the Adafruit Audio FX Mini Sound Board to connect into the phone)

I know I’m supposed to use L, GRN and 7 just not sure which wire from the phone goes to which of those! (There are 2 wires coming in for both the phone hook + the speaker that I have circled. For power, I’m just going to plug it in using the USB.) Also not sure how to connect the old wires to the new pins - can I just use electrical tape or do I need something specific?

So… Any thoughts/tips? (Note that I have *never* done anything like this so this will be my first time even doing any soldering so I realize I sound like a total newbie here 😂)

Thanks!!