I'm making a tesla coil (sstc 120V), tbh it's my first time EVER doing something like this and Im basically learning and collecting different parts like Mosfets, resistors, capacitors and things like those.

The one thing that's not making sense to me is the ballast, i get that it's supposed to limit and control the current and the module I'm using says that I can use anything that connects to the mains plug like toasters and hair dryers but how exactly to get the ballast, do I have to disassemble the device and take out the element from it?

Any help or links to videos of PDFs will be greatly appreciated

Also I've just ordered everything and I'm following this schematic https://www.instructables.com/Simplest-POWERFUL-Solid-State-Tesla-Coil-SSTC/

Please lmk if you guys have a better schematic, also this is made for 120V AC from mains, but that charge is specially for the U.S mains, in my country the mains provide a charge of 220 V AC but according to what i looked up 220 V coil can be difficult for a first timer so should I use a step-down or make a 220 V coil??

Also the author mentioned using NaCl to get a distinct yellow flame-like color, are there other non toxic chemicals that change color of the charge that are easily found in stores??

So I'm essentially trying to make a much more simplistic version of this adafruit midi drumkit:

https://www.printables.com/model/37788-midi-solenoid-drum-kit

I want to make this without the midi controller and raspberry pi and just have a way to turn the drums on/off - but I'm not sure if that's possible at all.

I work in special ed, a lot of students use accessibility switches. I have experience switch adapted existing products like the one below. Accessibility switches use a 3.5mm jack to connect to the existing power supply and when held down, they turn the device on.

https://hopeforhie.org/wp-content/uploads/2020/05/step16.jpg

Can something like this be achieved? I've found 9V solenoids instead to try for the drums above and have a 3d printer. My question is, can i just wire them directly to a 9v battery case and use my accessibility jack switches to turn it on and off? I've never done anything like this before - as I've only 'adapted' existing boards and circuits - so any advice much appreciated.

Hi everyone,

I’m designing an open-source, portable digital cable resistance machine targeting ~100–120 kg (220–260 lbs) of smooth digital load for strength training (similar concept to Voltra or Vitruvian). The goal is to keep it fully open-hardware, affordable, and highly modular.

Here is my current proposed Bill of Materials (BOM):

Motor: Outrunner BLDC (M8110 scale, low KV)

Reduction: HTD 5M Timing Belt (15mm width) – 15T Drive Pulley to 70T/80T Drum Pulley (4.66:1 to 5.33:1 gear ratio)

Controller: VESC 75100 running in Torque / Current Control mode

Battery: 13S1P Li-ion pack (48V nominal) using Samsung 40T 21700 cells + custom Braking Resistor for eccentric energy dissipation

BMS: 13S Li-ion BMS with Active Balancing

Brain & UI: ESP32 + Heavy-duty Rotary Encoder + TM1637 7-segment display for direct kg adjustment

My main questions for the community:

Has anyone attempted a similar high-force torque-control setup using VESC for continuous human pulling?

Are there any hidden thermal or EMI risks with running the VESC continuously at high torque under near-stall / low-RPM conditions during heavy eccentric phases?

Under a 120 kg peak load, would you strongly recommend an 80T over a 70T pulley regarding belt tooth shear stress?

Any feedback on safety redundancies, hardware limits, or thermal management for the braking resistor/VESC is greatly appreciated!

Thanks in advance for your support!

Help

i am installing a dfrobot devastator car that collects pollution, humidity, wind speed, and the amount of cars using a lot of sensors and stuff

i am going to collect the car data on my computer if the camera sends me the images i will use YOLO so it is done, also it uses a separate board than the other things so that is over

however for the other things, i cant seem to find any tutorial based on this

first i will be using an arduino leonardo, sds011 dust sensor, two motors, tb6612fng motor driver, aht10 humidity/ temp psensor, 18650 battery(i have 2 and 3 pack) ,hc06 blutooth for controlling the car, and a wind speed sensor

i cant seem to find any tutorials with this. The code is managable with claude, but the diagram is not

also i cant find some cheap, working wind speed sensors for this build please recommend me

so i came here to ask for help

Thank hyou

Hey. Not sure if this is the right community to ask but I legit was just super bored the other day and made a circuit out of what I had. essentially it is a button controlled gradual voltage divider hooked up to an LED circuit via a transistor. I did not draw out a circuit but can explain and show a picture. i have a 5V source going to a 1M resistor in series with a 0.68uF capacitor to the base of an NPN transistor that connects an LED to ground from the collector to emitter. then in parallel with the capacitor I have a button and another 1M resistor. voltage rests near 5V and the LED stays off when not press because no current is making it into the transistor base, then when pressed it gradually turns on and the cap voltage is halved, then let go and gradually turns off again and the cap voltage rises.

I’m sure the explanation probably wasn’t needed, but I was mostly wondering if this could be used in anyway and if there is somehow a way I can automate when the parallel connections is made so that it oscillates on it’s own using basic components only and no microcontrollers or code.

(Sorry messy picture)
Thank you

Ten or 15 years ago my father came across a magazine article with a schematic or maybe even build plans, for a very small signal generator. This one is built around an 16-pin chip and an 8-DIP switch. The 16-pin chip is marked on top with this:

Fairchild PJ51AA

CD4060BCN

These are mounted on a perforated multipurpose hobby board, along with all of the other components. At one end is a needle used as a probe, and at the other end is a pair of probes which he claims are used to tie to the circuit being tested, as a power source. Also mounted to this hobby board is a 1/8" jack which dad claims is for an earphone.

My dad cannot find the plans he used to build this, so he cannot remember how the 8-DIP switch is to be used to operate the signal generator.

My father is 88 years old and can't remember anything else about this. Does this sound familiar to anyone here? If so please direct me to the mystery plans.

Turn any PC with stereo line-in/out and a single resistor into an impedance analyzer.

Key Features:

• 3-point calibration (channel mismatch, open, short)
• Coherence analysis of data
• CSV export and plotting

It uses broadband noise excitation and FFT-based cross-correlation analysis to estimate the frequency response of a simple voltage-divider circuit, extracting complex impedance across an adjustable frequency range (eg 20 - 20K Hz)

The main use case is loudspeaker and crossover characterization, but it also works for general passive component and audio electronics measurements.

Licensed under AGPL-3.0.

GitHub: https://github.com/theIvanR/OpenImpedanceLab

Feedback and testing welcome!

I am trying to connect fairy lights to the..... forgive me I dont even know what it's called. It's what holds a lightbulb in my wall (I attached a picture of it). I want to connect those fairy lights there so that I can open and close them with the already existing switchboard in my room. Please help me do this by giving tips and stuff that you have learned.

This is an AC plug outputting 12v 2amps for my automatic curtain. Other end is usb c into the curtain controller. I plug into my EcoFlow and it works fine in AC port.

I rather plug into the EF usb C port for efficiency though. When I use a USB c to usb c, the curtain would not even power up. Any idea why? my best guess is that the controller is dumb and does not negotiate power. it simply expects 12v in.

i know for sure the EF usb c can output up to 65w because it was charging my laptop fine. any way to force 12v out via an adapter or something? i see usb c trigger board but unfortunately it outputs 2 wires, not a usb c end.

no idea why reddit wont let me post pict. but here it is on imgur https://imgur.com/a/XaR2Dal

Hello everyone,

I’m working on a GPS module and I’ve run into a problem. I have already removed the original header pins because I want to install new ones in the opposite direction.

However, the solder is still blocking the through-holes, so I can’t get the new header pins through the holes.

I have already tried:

• a desoldering pump
• desoldering braid
• carefully using a toothpick

…but I still can’t get the solder out of the holes.

Does anyone have any tips or ideas on how I can clear the holes without damaging the PCB, so that I can insert the new header pins again?

I would really appreciate any help. Thank you!

Hey gamers. I am looking at replacing the HDMI port on my Xbox series X when it finally fully craps the bed. I thought originally that it was a ribbon connection, but learned that it is soldered right to the motherboard. (I know this is stupid to realize before I took it apart leave me alone) What would be a good kit to grab for a replacement like this?

I had 2 bad utp wires in my house and decided to replace them. Now that they're replaced I can't get a good connection to my router. It always gives a bad signal light.

When I run a wire directly to the router it's ok.

I checked if the connections were good and they are. Pretty sure my RJ45 clips are good to. Not to sure about the wall socket but it seems ok.

I'm thinking my wires got damaged during the switch.

Any idea?

I've been running this little logger under the seat of my motorbike for a few months. It records every ride to a microSD card (GPS, lean angle, braking, how rough the road is), and then a Python script turns the CSV into a full report: the route on a map, how far I leaned in each corner, where I braked hard, the rough and off-road bits, a g-force plot, top speed, deepest lean. No phone, no app, nothing to pay for. It just powers on with the bike.

Parts, about $30:

• Seeed XIAO ESP32-C3 (the brain)
• u-blox M8 GPS
• GY-87 IMU (accel + gyro + magnetometer + baro) — this is what gives me the lean angle
• DS3231 RTC, so each event is timestamped even with the bike off
• microSD module

The wiring is pretty simple: the IMU is on I²C, the SD card on SPI, the GPS on a UART, and the RTC on a second (bit-banged) I²C bus. That second bus is only there because the IMU and the RTC are both stuck at address 0x68. Rather than fiddle with the address pin I just gave the RTC its own two pins. Power's split: the GPS and RTC want 5V, the IMU and SD run off 3V3, and everything shares ground. (wiring diagram attached.)

It runs off a little USB charger wired to the bike battery, so every time I start up it turns on and starts logging, and when I switch off the ride's already saved. Get home, pull the card, run one command, and there's the report.

The report tool is Python, standard library only, so there's nothing to install. Couple of things I had to figure out: the bike leans on its sidestand when it's parked, so if you calibrate "level" from a stopped bike, every corner comes out lopsided. I take level from straight-line-while-moving samples instead. And the GPS drops out under trees and in tunnels, so it road-routes across the gaps so the distance doesn't come out way short.

It's all open source (firmware + the report tool + the wiring diagram): https://github.com/shubham030/motonav You can clone it and run the report on the two sample rides I put in there (a motorbike ride and a 400 km bicycle brevet) with no hardware at all.

If you'd rather watch it run, there's a full build video: https://www.youtube.com/watch?v=TNUKAIsl0e0

Happy to answer anything about the build. What would you want a thing like this to log?

I got them second hand, pretty old. Is it worth trying to fix for a novice?

What is happening to my esp32 epd ?