Recently bought one of the Freenove Raspberry Pi Pico Kits and got stuck on the first "blinking led" project.

Well, I did make it blink alright, but got more questions than answers.

Why did they make me use this specific pin? Why resistor? Why 220 Om resistor? I see LED's datasheets, ohh so they've got max voltage and amps, got it. Resistor protects the led, mhm, okay. But wait how do I pick right resistor for my led? If I connect a battery instead of usb, how will it affect overall circuity in terms of amps and voltage and how do i pick a right resistor then? Why LEDs and diods allow the current in only one direction? How is it useful in DC circuit? And why do i even use pico board to blink a led, isn't it an overkill? How can I achieve the same result with less? Without microcontrollers? What IS microcontoller? Why does it have to "sleep" more often than I do? Are signals sent from pins somehow different than analogue electricity? How? Etc.

In other words, tutorials are easy af to follow, but they frustrate me by not teaching anything neccessary to create my own circuits

So I went to allaboutcircuit.com to learn the basics. I thought i'll just refresh my memory on Ohm's Law, in and out, surely that's all there is about circuits to consider

Well, nah. Just reading the table of contents gives me nausea. Kirchhoff's law? Electrical transients? Reactance and Impedance? Calculus? I never heard such words before lmao. And the textbook is quite massive. I also picked up from nand to tetris book to figure out how computers even work

Don't get me wrong, I'm not saying I don't want to learn all of this. Quite the opposite. But I also wonder if i shoot myself in the leg by digging too deep into basics of basics while letting my pico board collect dust on the shelf

I've done this before in other fields. "Oh, to do this stuff, i first need to learn this, this, this, and that, oh and also that, and only then i'm ready". I got burned out quickly and haven't made anything. Sure, I learned some stuff. But I'm gonna die one day and my knowledge with it. I wanna MAKE, put it to use

What are your thoughts?

UPD: the projects i wanna do in near future are macro keyboard and handheld tetris. But I don't want to blindly follow other people designs without understanding why they made it like so

Hey y’all! I just started getting into building effect pedals, I’m very new to it so a majority of the pedals I’m working on are utility pedals (passive volume adjusters and the like.)

I want to build a loop switcher (a switch that routes audio from an input to a send/return and then to an output or bypasses.) I have found a lot of schematics on how to build this, but none that can program Send/Return Loop 2 to turn off Send/Return Loop 1 for instance. Is this something easy to wire or are we getting into chip programming territory?

Pardon my lack of proper terminology, as I said I’m just getting into it. Thanks!

Basically just as the title says. I want to start making model trains but im not fully sure how i should go about it. They seem simple enough, but i want to make sure im not going to burn the house down. Does anyone know of a good youtube video/series or perhaps an online course that could be helpful?

(don’t know if this is the right sub, but this is all i could find)

I recently got one of these pocket LCD game keychains, similar to Tamagotchis or Tiger game consoles. I’ve had it for two weeks, and it developed this weird fractal pattern on the right side of its LCD. I tried rubbing it off, to no avail. I think it’s on the inside, but I can’t get into it because one of the screws is stripped. Anyone know what it is?

My Instax mini 40 is stuck on s and won’t turn off. I have changed the battery and try to see if any film was stuck and even changed the film. I don’t know what to do and every time I try to look up something to help me it only comes up with the mini 11.

The light starts flashing after I try to take a photo and I can’t seem to figure it out. If you have anything that would help please comment anything that would help me.

I bought Serena shades from Lutron last year. We opted for battery powered because they promised long battery life. The batteries are dying around the 8 month mark. Some of my windows are really hard to get to, and high. Switching out the batteries is a huge pain in the ass. I wanted to run low voltage wire from a power panel but on their site it says that battery powered shades aren’t convertible to wired, but it looks like a 18 awg black and red wire coming off the battery housing to the motor.

Is there a reason I can’t splice power into the wire and run them that way?

For the life of me I can’t find a push-pull potentiometer that also has a transparent/illuminated dial. Has anyone seen anything like this? Or even a pot with a transparent shaft and a depress ability so I could slip an illuminated button underneath? I’ve seen pots with buttons and pots with illuminated/transparent shafts, but I haven’t found a pot with both.

Hello, I’ve been trying to find info on this but I am looking for PSU test leads. I will be using these for proto boards, powering arduino projects, LED, motor control. Everything I have found is for multimeters. I think I would need banana clip to a probe that has interchangeable tips such as mini grabber hook and alligator clip. Any brand and model recommendations? I have a 30V 3A PSU. Thanks!

Could I use these 3 products to make a light that could plug into my Xbox’s usb port?

Amazon links to the 3 products:

https://a.co/d/bCoO2X6

https://a.co/d/5pyMxuf

https://a.co/d/0rV8QH0

Thanks to anyone reading.

https://preview.redd.it/0fkqah8dg54e1.jpg?width=440&format=pjpg&auto=webp&s=49feb0de0028a5e77bf072925d53493aa2e272fc

Where instead of the top being an Input, it is instead a display for the input. I hope this makes any sense at all, I need it for a first fun project, so I am new to this and don't know what to look for namewise.

I bought this ultra small 3v to 5v dc booster. When I connect it to a 3v battery, theres no output voltage. I tried to add a load to its output but there is still no voltage. How do i turn this on?

I have a robot vacuum and I would love to have a wireless webcam on it so that I could watch where it is going and see what is going on at my apartment when I am not home. I have this Roborock app that I use to remote control the vacuum, so the camera will only be used for viewing. It would be nice if it could draw power from the vacuum, but it is not a must.

Has anyone succeeded in making something like this? Please reply. Which camera did you use and how did you set it up?

With Christmas coming, relatives are asking what I want for Christmas, and all I can think about is how beneficial having my own oscilloscope and bench PSU would be. However, I know very little about the inner workings of an oscilloscope and what's good or bad, let alone how to ask family members for one as a gift. After reading the wiki, I'd still like some input from strangers on the internet.

SCOPES

Budget: <$200 is perfect, $200-$300 is doable, anything over $350 is out of the question.

Type: Either. Digital will likely better fit my desired features, but I will happily take a cheap, usable, quality analog scope. This is my first scope after all.

Channels: Happy with 2, any more is a plus.

Use case: Mostly just to view a waveform and its amplitude/frequency. I do a lot of projects with audio synthesis and signal processing/filtering. In the future, I'd like to explore power systems, audio systems, RF, and maybe some microcontroller stuff, but that's less of a priority.

Bandwidth: See use case. Whatever works works.

Desired Features: Autoscale, single shot capture, and recording to USB. Trigger is probably important too, although I have rarely used it in my three semesters of college (maybe that's just a skill issue). I can't think of any others.

My local MicroCenter sells Siglent Technologies SDS1052DL 50 MHz Digital Storage Oscilloscopes, and from what I've seen, they seem to be solid scopes and meet most if not all of my criteria. That said, I don't know if the linked scope is worth it, and I know buying used is often preferable. What have been your experiences? Are there any better scopes out there?

POWER SUPPLIES

As far as power supplies, I've chosen to rely on the wiki and ask for a used HP/Agilent E3610 or a new Korad KA3005D. To those who own or have used either of these, what has been your experience? Is one better than the other given that they cost about the same?

Thanks for your feedback! This is probably needlessly long so thank you if you've read this far!

TLDR: I'm asking for a scope (Siglent Technologies SDS1052DL) and PSU (used HP/Agilent E3610 or new Korad KA3005D) for Christmas and I'd like some insight.

This is one rectangle polygon on a user layer of copper I am using for connections outside the picture. I have 4 vias (one is within the big copper rectangle). On this layer I would like the via not to connect.

What is the technique to create an exclusion area around the hidden via. Can I put in a circle and open the rectangle, I have not been successful. These are just shapes I'm using as I don't need a schematic and nets for this simple project, just using shapes.

https://preview.redd.it/5f9s1fsy834e1.png?width=1191&format=png&auto=webp&s=2ad5be112afd861203b9d19f47452570a71073a8

Hello everyone. I recently bought a used Vevor Ultrasonic cleaner that is not working. I searched and followed some of the advice from this post in this sub.

I believe the problem has to do with the power supply. The machine's plug has a power switch in the back, which lights up orange appropriately when turned on. When the switch is on, the main fan turns on, however the main LED display, which is on a circuit board with buttons to control the unit does not light up and only beeps when plugged in.

I took the machine apart, and found that the voltage to the fan is only ~ 9V, and the voltage going to the LED display/ control fluctuates between 1.6V and 2.2V. I took a video explaining and some additional photos here: https://imgur.com/a/gQusb4o

Everything on the control board is labeled as 5V, and I have verified it works properly by plugging it into a bench power supply at 5V and it lights up and the buttons work perfectly.

I'm not familiar with the main board of this unit, and I'm honestly not sure where to go from here. Any advice would be greatly appreciated.

Thanks

https://preview.redd.it/p2ewoewnn44e1.png?width=2632&format=png&auto=webp&s=26625ea078443112c9117b3eb0880dcdd3d349ed

Hi, y'all. I am trying to design an ESC for a BLDC, and this is what I have come up with. Are there any major problems or changes I should be making, or does it seem like it won't set itself on fire? The motor will be powered by a 4S battery.
I have the resistor network for the virtual because I wanted to step down since the comparator cannot handle a too-high voltage.

Also in an ESC, is the PWM the only signal given to it, or is there something else too?

Thanks.

Hey,

So I have this old 2009 LS21 Logitech 2.1 stereo speaker system lying around that I actually kind of like. However, the amp board has some defect so the left speaker isn't really working well, sometimes it is when wiggling the connector that connects the stereo sound boxes to the amp board via simple audio jack.

I thought it's the connector, but the boxes work fine elsewhere. I also cut the connector open and soldered the cables directly to the amp board. It's always the same channel sounding very dull.

So I already thought it's the amp chip (Boomtech BT2025BH) which I consequently replaced, though I just a design copy called TEA2025B. But that didn't solve it neither.

The caps look all god. Should I just replace them anyways? Or how could I go about it?

Modern mice sense how far the mouse is lifted off of the surface below, and stop responding above a certain height. How is this distance sensed/calculated by the optical sensor? All my intuitive thoughts on how this would be done seem to be incorrect.

Background:

I am looking for a hardware solution to bypass liftoff distance. That is: I'd like to mod my mouse to be several millimeters taller, and the easiest way to do so would just be putting risers on the bottom, but obviously then the mouse stops working.

My mouse (Logitech MX Anywhere 2S) doesn't allow LOD to be changed on the software level, which is why I am looking for a DIY hardware solution.

My instinct is that some sort of magnification lens in front of the sensor would be a decent solution, but in looking for info on if that would work, the only related thing I've been able to find is the Magic Mouse mods like "MouseBase" which use... vertical mirrors on either side of the sensor? What?

If anyone can help me understand the mechanism by which LOD is calculated by the mouse, my hope is that I can figure something out from there.

At this point, I'm also just curious for an answer as there is surprising little info out there on this

I have changed the housing of the keys because they were very old and dirty, the problem has been that removing the key pin I have destroyed and ripped off the board 3 SMD components of the same. I have found a video where I can more or less point out the 3 components.

SMD component removed

SMD in video

I know one of them is a capacitor and the other 2 are two resistors.
Can i put some random value? Or where can i find the schematics of the circuits. The main chip is this one:

https://preview.redd.it/q3x0sqzbq44e1.jpg?width=640&format=pjpg&auto=webp&s=ec7135ee4b9e5f3b9ec902cea4aa7e27900e0337

Hi about a decade ago I moved a vintage Technics SA-5160 into the garage at our family's (in-law's) seaside condominium. It was all fun and games until I realized last week that no one, on either side of our family, ever moved the unit back indoors.

For a decade now the unit has been sitting there and the sea air has been slowly corroding all the things inside. Today, I powered the unit up but did not hook up speakers. The unit lit up but I heard some low level sizzling and smelled heat and other smoke like odors. Total time on was about 30 secs before I killed the power.

What are the first components I can troubleshoot? How to troubleshoot? Is this thing savable?

Were tasked by our professor to make an ADC circuit with LM324 and 74LS148. Bases on my brief research, I have seen that the inputs either at the inverting input or non-inverting input that makes this confusing for me. Does it depend on what the DAC is output-ing? Because the complementary DAC, that was also tasked us to design by our professor, has an inverted output.

https://preview.redd.it/tdwkpqe6t34e1.jpg?width=2592&format=pjpg&auto=webp&s=41947a2159bfe6c3ade74f6817f0c1260b6c9884

I can't figure out what the two white components are as they don't seem to read anything on any of the settings on my DMM, with the exception of 0.1nS for one, and 0.6nS for another one, so I'm guessing this doesn't help much.
The two resistors are both 137kOhms, and the IC is an Analog Devices AD8647.
The components have been measured after being desoldered from the PCB to make sure the measurements are correct.

https://preview.redd.it/i76bohhvu34e1.jpg?width=2592&format=pjpg&auto=webp&s=080b4d0e7038d0e3c1d199f7a5aa524977acdff2

I also can't seem to figure out what IC this is.
The only information I have is that some of the boards I have has the marking "CN6C", and some has "CN11", and all other ICs seem to be from reputable manufactures like TI, Analog Devices, Microchip ETC, so I would assume this is a "good", well known component as well.
It also looks like a SOT-23-5, and the pins go to the following components:

Pin-1 to pin-24 (PC4) on s STM32F205RCT6
Pin-2 to GND
Pin-3 to pin-50 (PA15) on the STM32F205RCT6 and pin-1 (SCK) on a MCP23S08
Pin-4 to the pin-52 (PC11) on the STM32F205RCT6 and pin-12 on a ICL3221EIAZ
Pin-6 to the output of a TPS73033 regulator

I'm trying to reverse engineer some PCBs, but I'm quite new to electronics, so I just can not figure out what some of the components are.
Help would be much appreciated!

I used it many times in the past to check batteries and our RV circuit drains.

Picked it up today to test some DHT11 sensor. Resistance and conductivity tests went fine, then when I tested the voltage VCC vs. GND instead of showing me ~3.3V, it shows 1.7V. I then tested using a 5V supply and it showed 2.4V.

I then tested with a new 9V battery and it shows 4.6V. Seems consistently halfing the actual readings

Any ideas why it does this now? I put in a new 9V battery recently.

I am no professional so I do not use it very often.

I may or may not have done something to caused this. If so, any idea what it could be? I'd like to avoid that in the future if I need to by a new one.

Thanks

I have a transformer on an old guitar amp that needs to be replaced, and since it dates from the 50s, I can't just use the part number to find a new one. The transformer is the one going to the speaker.

What I know:
- The amp is 18 watts.
- The speaker impedence is 8 ohms.
- The primary coil has a center tap.
- I'm pretty sure the windings melted because smoke came out when I plugged it in, so the winding resistances I measured are probably useless. But here they are anwyay: 900 ohms, 500 ohms and 400 ohms on the primary windings and 2.8 ohms on the secondary.

Here's the schematic. The transformer I'm talking about is the one at the top right of the schematic.

https://preview.redd.it/2qucru0cb44e1.jpg?width=3024&format=pjpg&auto=webp&s=d24eab0fecaa72295f1b285a3daa2a6521ec7539

https://preview.redd.it/f4ghzv0cb44e1.jpg?width=3024&format=pjpg&auto=webp&s=f5f71f5ebfa237ddab8997e711210a41c484c4ff

https://preview.redd.it/kmhjrx0cb44e1.jpg?width=3024&format=pjpg&auto=webp&s=339f032210a0d7c59234e5a5125e9cba66d7745d

I'd appreciate if anyone can give me an idea of the specs needed for a replacement, or an example of a transformer that would work. Thanks!