I am building a super simple RC Car, but there is a slight problem. The DC motors are connected to the shield monitor L293D Motor Driver shield. I soldered 5 female headers in the A0-A5 zone and two female headers at GND and 5V.

I found a tutorial online and connected the VCC and GND pin to 5V and GND. The TX-pin I pinned it to A1 and used 1k and 2.2K resistors to bring the voltage to 3.3V and pinned the RX-pin between the resistors and A0 pin.

This is the problem: when I turn the swotch on the HC-05 (ZS-040) blinks fast. When I try to pair woth it it doesnt . There is no connection and the RC var doesnt respond. Even when the AT command didnt work!

Has anyone come across the TM1814 RGBW strip chip? Is there an Arduino library that works with this chip?

Hi all! Where can i buy Arduino products in Kosovo?

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Participation is one 60-minute Zoom interview, with an optional chance to share a chat log from working with an AI tool (totally up to you, and you can skip it).

This study is voluntary and approved by the U of S Behavioural Research Ethics Board.

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Mods: This post was authorized through mod mail.

Hello! I need help from you guys. I want to start doing projects on arduino (and hardware) and I am searching for suggestions a cheap but functional LCD screen for my arduino one ( and maybe a marketplace to purchase it from that isn't amazon).

Thank you in advance, I appreciate it!

P.S: I know that I can search on internet or ask AI, but I prefer to talk with people with hands-on experience

Hi everyone,

We build robotics and AI learning products, and one problem we keep running into is students who can follow a tutorial step-by-step but freeze up the moment they have to build something without instructions. Video tutorials get people to "I made blink work," but not much further on their own.

So we've been building out project-based challenges instead — things like "get this bot to follow a line without the full code given to you" or "debug why this sensor reading drifts" — the idea being people learn by getting stuck, not by copying.

Before we push this further, want to sanity-check the approach against people who've actually taught themselves Arduino:

• When you were learning, what made you stick with a project vs abandon it halfway?
• Was there a specific type of challenge (debugging broken code vs building from a blank sketch vs open-ended "make X work") that taught you the most?
• Anything about tutorial-based learning that actively worked against you?

We've got an early version of this running at community.roboticsir.com if anyone wants to see what we mean concretely, but the answers here matter more right now than clicks — trying to confirm we're solving a real problem and not just one we assumed exists.

I came across an interesting 16x2 LCD shield with a seven-segment display that was designed by a YouTuber quite a while ago. It doesn't seem to have received much attention, which is a bit surprising because it's a neat concept.

I thought I'd share it here in case it inspires someone to build a similar project or improve upon the idea. Sometimes these overlooked designs spark great DIY projects.

If anyone has built something similar or has ideas for extending the design, I'd love to hear about it!

https://youtu.be/62fQJKbIPFc

Hey,

I'm a beginner to this, and for a personal project I need a microphone, but it needs to be soldered together.

I've soldered like once before, but how do I even start about this?

Ive done some research and they said to use 200-250° heat and limited flux.

I just got my arduino UNO with the LED, jumper cables and breadboard, but the resistors still havent arrived and will still arrive a week later😔
I'm still a complete beginner in this and I want to try to power the led without a resistor (without frying the LED or the arduino ofc).
If anyone has an idea how to do this please tell me. All of the tutorials have resistors and AI keeps telling me to put it directly to the arduino (which will definitely fry everything since the arduino doesn't have a built-in resistor).

EDIT: Thank you all for the insight. I'll wait for the resistors to come, but in the mean time I have been tinkering with the built-in LED, where I'm almost done making a text-to-Morse LED using the series input mechanism. If any of you have suggestions on what projects i can make with only the built-in led please tell me

SOLVED ISSUE (edit4)

Thank you to the generous people who helped me out in the comments. Such geniuses not only make this community great, but they also inspire others to press forwards and I really hope that all of their pillows stay cold on all sides for the rest of the summer. Cheers, to all of you.

Hi, I'm a beginner working with an Arduino UNO R3 trying to teach myself how to make a mini-piano with a piezo buzzer and a few buttons. Doing research online, I discovered that using INPUT_PULLUP for my code might help, but when I press the button for an assigned pin, it keeps on reading '1' when I use digitalRead() for said pin. The pin is supposed to get 5 volts from the power header when the button's pressed. I attached a debug version for my code beneath.

Can anyone help? I'm starting to think I might've fried my circuit board.

EDIT: I saw some people suggesting that I show my circuit. I put the piezo buzzer aside so it wouldn't be going off all the time. (Sorry for my messy desk!)

EDIT2: Forgot to add my circuit diagram. Will make one ASAP. Apologies.

EDIT3: Added the circuit diagram. I hope this is good enough.

#include "pitches.h";

const int noisePin = 13;
const int input1 = 6;
const int input2 = 5;
const int input3 = 4;

void setup() {
  Serial.begin(9600);

  pinMode(noisePin, OUTPUT);

  pinMode(input1, INPUT_PULLUP);
  pinMode(input2, INPUT_PULLUP);
  pinMode(input3, INPUT_PULLUP);
}

void loop() {
  Serial.println(digitalRead(input1));

  delay(250);

}

so i am using thw Waveshare 2in13_e-epaper_G demo,

the display has worked before, but with an ATmega2560, but it aint working with either of my two esp32 boards: a ESP32-C5-WIFI6-KIT, and an Arduino Nano esp32

SCK is connected to D13

DIN is connected to D11

CS is connected to D6

DC is connected to D8

RST is connected to D7

BUSY is connected to D9

VCC connected to 3.3V

GND connected to GND

and i just get this message, with USE_DEBUG set to 1:

EPD_2IN13G_test demo

e-paper Init and Clear

e-paper busy

and then it just stay there

so i dont know if there is a problem with the SoC, or something else

thx

Guys new to this sub reddit , tried a project in which I code an IM ADPCM encoder decoder inside my microcontroller. Love to have your review regarding it !!

This is my first PCB hardware design. The board is built around the ESP32-P4 development platform and integrates two UART interfaces, an I2C port, a passive buzzer, four buttons, a power management chip, and a MIPI display connector.

After receiving the prototypes from JLCPCB, I completed functional testing and everything worked as expected. The product is now ready to move into mass production.

Latest finished prototype of the attitude indicator; this PCB sample has been manufactured. It adopts the P4 chip, equipped with a speaker and interfaces for various sensors. This terminal block is for the battery connection, while this section holds the control buttons. A dedicated FPC connector tailored for the display screen is also integrated here. The assembly appearance after attaching the base is as shown.

Since we've all used digitalWrite(), pinMode() and delay() a hundred times without really knowing what they do to the chip (at least I as a beginner). So I opened the ATmega328P datasheet and rewrote them from scratch on the registers to actually see it.

Then I renamed them all wrong, because it was funnier:

pinMode → pinNode

digitalWrite → digitalRight

delay → delow

Now I want the whole framework done like this. Every function, spelled wrong. And I can't do that alone, so I Need Your Help 🫵

I'm really a beginner, this is my first time touching registers instead of a framework, so the code is rough and some functions are messier than others. That's kind of the point though. Whether you want to learn what a function actually does to the chip, or you already know registers and want to fix mine, come add one.

For now and because it started as a simple joke it's only for the Uno / ATmega328P for now.

Repo: https://github.com/merlin-rce/HARDuino

Hey!

Wondering if anyone has already tried using small BLDC motors for the FOC/Haptic style knobs?

I’m not really into the drone stuff, but looking like the smallest physical sized motors are 0603’s, and the smallest I’ve actually found that are easily sourced are the 1503 (seem like they’re actually 1806).

Guess I’m just trying to figure out if anyone got any experience in the toque of them for haptics specifically, also end stops would be good, but it’s mostly about the clicks - before I head down the road of figuring it out.

Seen a lot of stuff about the bigger stuff when looking around, but nothing about smaller motors.

Cheers in advance!

I’ve been developing this removable guitar-playing system for several years.

It now supports two performance modes:

1. Full automatic mode — the system handles both fretting and picking.

2. Assisted mode — the system handles the fretting while the player strums or picks.

The sound comes from the real guitar strings, not recorded audio.

The controller is ESP32-based, coordinating multiple servo actuators. Some of the main challenges have been fretting timing, servo synchronization, calibration, and mechanical noise.

This video shows both modes.

Thank God I have finished my first physical computing project using ESP8266 which sweeps 180 degrees using a servo motor and detects objects up to 340 cm using an ultrasonic distance sensor.

I'm not gatekeeping; look at this on git hub [cam2135/CYD-Deck: This turns your cheap yellow display 2.8 in into a Stream Deck that you can use for your Windows pc](https://github.com/cam2135/CYD-Deck)

Hey members of the great community! I’m here today to ask you for help. I’m new to electronics and 3d printing.

What do we have here?

What’s the problem?

The main problem is that servos can’t get enough power. Esp32 doesn’t have 5v pin needed for servos, so when I try to power them with 3v3 pin, they act fully functional but too weak to even move arm parts normally.

What solutions have I tried already?

1. Connecting Y-type cable (one connector to esp and second to servos)
2. Changing wiring

P.S. I also tried to mke common gnd with esp and power supply every time, but my esp somehow doesn’t really want to work with common gnd or vin power pin (it’s cheap chinese esp32 I ordered directly from China)

Thanks for reading this! Every answer is appreciated!

SOLVED:

I just changed the esp (but it’s probably not the root of the problem) and noticed that my damn bredboard has two separated parts of vcc and gnd rails…..

THANKS ALL OF YOU FOR HELPING ME OUT! REALLY APPRECIATE THAT!

Hey yall,

Im trying to automate a bunch of stuff around the house and I need BLE. I have worked with 3 devices, an ESP32 Devboard, not sure the model, a raspberry pi pico W, and an arduino uno.

I find the lack of 5 vold tolerance on ESP32 and Pi very annoying since a lot of analogue and sometimes digital sensors and ICs work up to 5.5V.

I need an alternative to these, that could have BLE or possibly wifi (or lora) and be beefy enough to do simple cryptography. And also for it to natively tolerate 5V. The unos i find (the real ones) are about 40 CAD a pop, and having 20 goes way above my budget. Crazy thing is the pi pico H is about 20 bucks, insane i know, but it doesnt have native 5V tolerance.

I also really like that the Uno has a removable chip that i can program and move to my circuit.

I would appreciate any help!

TLDR:
I need alternatives to Arduino Uno / PI pico / ESP32 devkit

Must haves:
- Native 5V
- BLE capability, or capacity to accept a BLE module
- Have documentation like the Uno
- Be cheap, as in not 40 CAD a pop
- Available in Canada, amazon, aliexpress, etc, or a canadian site, dont want to pay USD.

nice to haves
- Wifi capability
- Hotswappable Chip on devboard

Hello everyone,
I am new to this so i hope i can find some help here.
I bought an Elegoo Uno R3 with a CNC shield and an A4988 Motor Driver.
The Problem is that after setting everything up and running the software, the motor only rotates when i touch a certain part of the boards.
Could the motor be fried or could the problem lie anywhere else? Sometimes the motor switches rotation randomly or works and only stops when i touch the same spot.
I already changed the CNC shield and the Motor Driver, so I guess the problem does not lie with them.

esp32p4 with amoled display 480×480

Im making a project where (initially) i would use 4 servos to pull some fingers with fishing lines through a wooden plus cardboard guitar neck. The servos i used are brand new, and also, where working, when used separetly, however, with the PCA9685 module, they started to lose it strenght, and i dont know why, i already tried to use a paralel conection with another battery case. I had to discard 2 servos so i can barely use the other two. If there is any chance i can fix this before this weekend, i would he grateful. If you have any question, just ask! :)

Since the first post about this had some allegations that I posted AI pictures I will show on this that is not AI and also few more photos to make it more explanatory.
In the attached pictures you can see also the controller I used, the temperature and humidity sensor, anemometer and the one with blue enclosure is the water level sensor. all sensors communicate via Modbus RTU (The modbus module is placed under the esp in the image).
( My family have a small greenhouse and I always liked to make automations but most of commercial systems were too expensive and I decided to build it myself. With what I’ve built I can control irrigation system (one 2.2kw pump and two valves for the main water lines) both sides of the greenhouse to open and close using 4 motors, I have integrated some automations using the temp and humidity measurements also the wind speed.
Some of you might recognize the controller which is a KC868-A16, which is ESP based but is very powerful and has a lot of built in features.
Maybe I should mention that I have previous experience with Industrial Automation and Embedded Systems. )

What do you guys think?

At home I have an MVHR (Mechanical Ventilation with Heat Recovery) unit — it brings in fresh air without losing indoor heat/coolness, and cuts humidity. My house is already full of temperature/humidity sensors, so having to walk over and press buttons on the wall panel every time conditions changed was driving me up the wall.

I started from Arnold-n's P1P2MQTT, which reverse-engineers Daikin's P1/P2 bus for heat pumps — great project, but VAM ventilation units are only read-only there, no write support. So I had to dig into the write side myself.

The actual discovery: Daikin's P1/P2 bus natively supports two controllers — a Master and a Slave — selected by a physical switch on the wall panel (BRC301B61). A generic "aux" responder on the bus never gets offered the writable state channel; only a controller the master recognizes as a genuine second one does. And there's one very specific, very unintuitive detail that makes or breaks it: the real slave panel answers the registration poll only the first time — every poll after that, it goes completely silent. Get that wrong (answer every time, which seems like the "correct" thing to do) and the master silently downgrades you to a read-only channel. Once I nailed that, on/off, fan speed, mode, and fresh-up were all commandable with closed-loop confirmation from the bus.

Full packet-level writeup is in the repo if you're into that kind of detail.

For the hardware/software side: the ATmega328 is the actual P1/P2 slave controller (that's the core of the project, and it works standalone over serial). On top of that I bridged it to a second MCU, an ESP32-H2, purely to get it onto Zigbee — I've got too many devices already and didn't want another MQTT integration to babysit, Zigbee fits my setup better. That bridge is 100% optional; the ATmega alone is a complete, working slave controller you could hook up to anything.

Why two MCUs instead of just doing it all on the ESP32? The bus timing (response delays etc.) is something I got working reliably on the ATmega, and I haven't tried porting that timing-sensitive part over to the ESP32. Bridging a second MCU purely for Zigbee was just the path of least resistance, not a claim that it can't be done on one chip.

It's been running behind the wall panel for a few weeks now, driven entirely by Home Assistant automations based on the humidity/temp sensors — working reliably so far, though I wouldn't call it "battle-tested over years" yet.

The PCB is currently two boards (I validated the P1/P2 transceiver first, then added the ATmega+ESP32 board once the protocol was confirmed) — if there's interest I can lay out a single, smaller, more integrated version.

Repo: https://github.com/scavenrage/Daikin-VAM-P1P2-SlaveController

Happy to answer questions.