I bought a sewing machine recently and it came with a very sensitive pedal. They sell this other pedal which makes it possible to sew very slowly. £60 felt like a ridiculous price for this piece of plastic, but I'm not an electrician (I know some basics). Can someone please help me understand what the difference here is? Is it possible that I could achieve the same result by a simple modification? All I can see is the VR2 resistor missing in the new one.

Kds9 2h1?

I’m guessing it’s a sensor of some sort but I have no clue and Google won’t tell me.

So I've been using TVS diodes in all of my projects without really understanding how they protect the circuit, so I decided to do a few simulations

I got the ESD generator model from an article I simulated it and it worked correctly, but when I tried to apply the generator to a circuit I'm working on it didn't do anything?

What's the right way to do this? how do you guys simulate ESD events with accordance to IEC 61000-4-2??

I want to integrate an OV2640 into an STM32 project and saw that it requires a specific power on sequence. However in terms of powering down, I could only find the commands to power it down from software/MCU.

Do I need to power down the camera in a specific order, or can it handle unexpected power loss (disconnecting main battery) fine by itself?

I’m building a system using an ESP32, a relay module and a 5V solenoid.
The setup was previously working correctly, but now the solenoid doesn’t activate at all.
My setup:
ESP32 development board powered through USB.
Relay module with S (signal), V (power) and G (ground) connections.
5V solenoid connected through the relay.
Separate DC power supply for the solenoid.
Breadboard and jumper wires.
A web application built using Replit that sends activation commands to the ESP32.
The problem:
The solenoid doesn’t move.
The relay doesn’t make any clicking sound.
I’ve compared the wiring with photos of the previously working setup.
The wires appear to be connected securely.
I may have deleted the original Arduino source code, although I haven’t confirmed whether the firmware on the ESP32 was overwritten.
I haven’t measured the voltage or tested the relay independently yet.
What I need help with:
Can someone identify any obvious wiring mistakes from my photos?
I’m particularly interested in whether the relay is receiving power correctly, whether the ESP32 connections are correct, and what would cause the relay to stop clicking.
I’d appreciate specific troubleshooting steps to identify the actual fault rather than replacing components unnecessarily.
I’ve attached photos of the current wiring and the previously working setup.

Relatively new to Ansys, I want to run the Q3D extractor for a PCB. Ansys has been extremely pissing off, I can either import step files and get a 3d model, or ipc and get the materials but I can't do both at the same time. Can anyone explain the exact process in a Q3D extraction, and how I can get my PCB up there?

Even when I did figure something out it threw a lot of errors and intersecting components. The PCB is just a github download that I was using to learn the process before using my pcb.

Markings: B500K

Shaft: D type, 6mm dia, 11mm length. Push stroke 4mm, approximately 270 degree rotation

Bushing/mounting threads: 9.6mm diameter, 1mm pitch, length 10.5mm

Switch type: Push lock

I'm having no luck on mouser!

looks like a resistor but the band colours (silver, grey, brown, gold) dont really match up with how resistor band colours are supposed to be ordered im pretty sure. this is on an applevision 1710 crt and is on the deflector board. saw sparks fly out the bottom while it was on and found that this component was charred on the bottom. i also recapped this board recently, so that might be related. am i stupid and reading the colours wrong? please help!

Hi, I making a fan system with a led strip as a indicator. I am using a Buck convertor to step from 12v to 5v with a max of 10A to connect to a Raspberry PI Pico. The LED Strip I have also takes 5v. Could I Crimp the two wires together to power both device at the same time.

Hello, the drive in question has stopped working—it burned out. Upon opening it, I discovered a charred area where a capacitor (positioned vertically) and a diode (labeled D1, positioned horizontally) had been. Soldering a replacement capacitor in the vertical position did not get the drive working. Does anyone happen to know what type of diode should be installed in the D1 position? The damage is on the 5V line.

Processing img 753j6fs6c2yh1...

I am working on a light driver circuit which is powered from 2x18650 batteries.

I would like a circuit to safely switch to the usb-C circuit 5V when there is enough current advertised (Have this through an IC which checks the USB CC1 and CC2 lines).

I initially was planning on doing this via 2 Schottkey Diodes, but the reverse current was still getting through. I am after advice on switching this safely by a mosfet circuit arrangement or similar.

The bottom highlighted net is the voltage I need, the 18650s are connected via the right Schottkey, and the left Schottkey is currently the USB 5V.

I am seeking any advice :-)

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Theres no marking next to this component. Unsure exactly what it is ? Any ideas ?

Cheers.

I have a VFD (freqention drive) FUJI FRENIC MINI

my client asked me to control this VFD in speed and control on distance on his phone.

before it was a potentiometer that controlled the speed and a switch that give a FWD Command.

I builed with Shelly

1 shelly to start the drive for the FWD ( connection CM-->FWD)

Shelly 1 Gen3 | Smart Wi-Fi Relay Switch with Dry Contacts | Shelly Europe

1 Shelly dimmer to control the 0-10V to the drive (connection -12- / +13)

Shelly Plus 0-10V Dimmer | Shelly Europe

But the problem is the drive is changing the speed that i choose at the shelly dimmer on the shelly smart app but wenn the speed is corrected on the FWD. i see on the screen of the VFD that the frequention is climbing in hz by no reason to a higher frequention. until it reaches the max HZ , then it drops to the regulated HZ that the Shelly Dimmerin VDC is setted.

The current on the analog input is always constant this weird movement of the HZ.

Gemini was telling me this 0-10V dimmer is "Current Schrinking" so he schrinks the 0-10V thats giving from the drive. and he schrink it with PWM. That PWM causes this issue of HZ keep rising and falling back.

What Shelly does u guys Advice. There excist Shelly that are giving self 0-10V, would this be a solution. ANyone already tried this?

My son's toy walkie-talkie set came with a faulty speaker. The first photo shows it in-place - it's marked 8 Ohm, 0.25 W, and I measured the diameter as 29 mm.

I bought a replacement from AliExpress here, matching the impedance, power rating and physical size - as shown in the second photo (sorry it's blurry). But when I connected it up, the sound output was *much* quieter than the original.

Have I just bought a poor-quality speaker? Should I try one from a more reputable source, such as this one from DigiKey? Or maybe step up to a 0.5W speaker? How else might I increase the volume to match the original? Thanks!

Hey folks,

I’m looking to source a part (or potentially compatible) for the attached motor. It powers a thermostatic valve on a shower (Vado Identity). Whilst the motor 49YTD seems to be pretty common, this configuration I’m struggling to find.

Is there a specific place/source I should be looking for this? Will alternatives with different RPM/uF potentially be suitable? I’m willing to try most things at this point as it’ll be a multiple thousand pound bill if I can’t find a replacement for this.

Alternatively, on the off chance anyone finds this and has a IDE-145C-CPU, broken or working they’d part with, I’d love to hear from you!

TLDR: part broken, no spares from vendor, no alternatives, powers a remote shower control, will need to replace entire bathroom if no suitable part found as tiles also discontinued 🙃

Hi, I am an EE student and I am trying to make a closed loop bldc motor controller so that I can learn more about power electronics and pcb design.

I was trying to find a bldc motor with hall sensors but many motors online don’t have datasheets and don’t tell you if it is a sensored motor. So I was wondering if anybody has advice about a motor to choose, I’m also open to maybe using a motor with an encoder instead. I’d appreciate any advice.

Not sure if this is the correct sub but I have this light that turns on with a button but shuts off after a few seconds. I would like to make it stay on until I disconnect it from power via usb or plug?

Hello, as i said in the title I can't seem to find a site where i could order a load cell from that is high precision, i need it to measure the difference between euro coins.

So yeah if anyone could recommend a site that would be nice, thanks.(I live in slovakia btw).

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Hi everyone,

I'm an ECE undergraduate working on a research-oriented embedded systems project for the VLSID 2027 Design Contest, using the Renesas RA6E2 microcontroller.

The project explores detecting thermal sensor degradation while distinguishing it from legitimate changes in the physical process. The current concept uses two temperature sensors, physical-consistency checks, and controlled disturbances to evaluate whether sensor readings can be trusted.

Before committing further time, I want critical technical feedback from people experienced in embedded systems, instrumentation, control engineering, or industrial research.

Specifically:

1. What existing methods, papers, or patents already address this problem?

2. Is there a defensible research gap here, or would this mostly reproduce established sensor-fault diagnosis techniques?

3. What experiments and quantitative baselines would you expect to see before considering the contribution meaningful?

4. What are the biggest technical weaknesses in this experimental setup, particularly regarding two sensors, shared faults, and distinguishing sensor degradation from real process changes?

I'm looking for honest criticism rather than encouragement. If the core idea is insufficiently novel, I'd rather discover that now than after building the complete prototype.

Thank you!

I’m working on a senior design project using an ESP32 Feather V2 and an Adafruit TLV320DAC3100 audio DAC for Bluetooth audio playback.

I keep running into an issue where the DAC appears to pull the I2C SDA line LOW whenever I start I2S. When I stop I2S and reinitialize I2C, everything works again. The SDA line only stops working when I2S is started.

What’s even stranger is that I’ve tried unsoldering and resoldering connections, moving wires to different GPIO pins, and even replacing the DAC board entirely. All of these fixes work initially, even through several power cycles. However, when I leave everything overnight and come back the next day, the exact same problem returns.

I’m genuinely at a loss as to what’s causing this. Has anyone experienced something similar or have any idea how to fix this?

I bought an ESP32 with pre-soldered header pins, planning to connect everything using female jumper wires. Unfortunately, the space between the header pins and the battery below is pretty tight. I can technically fit the female connectors and get everything in place, but the wires have to bend pretty severely, and I'm worried they'll eventually break or lose connection. I cant use longer standoffs because its sized to a hole in the box for a usb-c.

I'm considering a couple options:

I could remove the header pins entirely by cutting off the plastic housing and desoldering each pin individually, then soldering wires directly to the board. However, I'm concerned about putting too much heat on the board and damaging it.

I could also solder wires directly onto the top of the existing header pins. This seems like the easiest solution, but the pins are pretty close together, so I'm worried about accidentally bridging two pins together.

Maybe just removing the pins that i need to use is best. im only connecting to GND, 3V, EN and a data pin.

Has anyone dealt with anything similar or has a recommendation?

Appreciate any advice!

I'm working on a project that will have 2 sensors, an led strip, and a touchscreen.

From my research I figured I would need a power supply more than USB C could provide, so I got a 5v 10A with barrel jack adapter.

I'm liking the Waveshare ESP32-S3 5in (https://www.waveshare.com/esp32-s3-touch-lcd-5.htm?sku=28151) for the display/controller, it has I2C for the sensors, and I can use the CAN connection for the LED GPIO's.

However the spec sheet only shows a 7-36V input option via the header. I'm only seeing battery or 5V USB otherwise.

Is there a 5V/GND connection I can solder to that I'm not seeing or do I need to change to a 7V+ supply. I'd prefer to stick with the 5V option so I don't have to buy a new 7V+ and buck converter.

Hi everyone!

I'm having a strange issue with my Honton R490 BGA rework station.

Whenever I start a heating profile, the machine runs normally for about 4–5 minutes, then suddenly reboots.

Here's what I've tested so far:

• Replaced the 12V power supply — no improvement.
• Disconnected the high-voltage power to the heaters, so the machine wasn't actually heating anything — still rebooted after 4–5 minutes.
• Sometimes, during the reboot cycle, the display shows an inverted image.

Since the issue happens even without heating, I suspect something is wrong with the main control board, voltage regulators, or firmware.

Has anyone experienced a similar issue with the Honton R490?

Any suggestions on what components or circuits I should check would be greatly appreciated!

Thanks!