Questions tagged [i2c]

Inter-Integrated Circuit (I²C) is a bus for low speed peripherals. Use this tag for questions regarding how to use I²C with an Arduino, or for problems with I²C and your Arduino.

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57 views

MPU6050 does not give output

I need help getting my MPU 6050 to actually give me data. As of right now, my program is only reading 0s from the gyroscope and when I move it, the values all go to -1 and the program just stops until ...
2
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1answer
48 views

I am in need of a usable communication library on 1-4 pins of ATTiny84 instead of I2C

I messed up when designing my PCB and just assumed that I could use software slave I2C with ATTiny84. The reason I did so is - I needed to use all of the analog inputs. The pins I have on my ...
0
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1answer
30 views

Multiple I2C devices connected to one Arduino Uno?

Is it possible to connect more than one I2C device to an Arduino Uno? I know that the SCL and SDA pins are on analog pins A4 and A5 respectively, but there are also two pins labeled SCL and SDA ...
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1answer
37 views

How to stop Single Analog Pin Keypad Matrix (Using Resistors) from receiving Interference from Livewire/other Sensors?

I saw a tutorial on linking a keypad using one pin, utilising several resistors: http://razibshahdat.blogspot.com/2018/05/one-single-analog-pin-keypad-control.html I have this keypad, a 16x2 LCD, a ...
2
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1answer
48 views

Can you use multiple arduinos to run two programs simultaneously?

If I want to run 2 different programs simultaneously, can I do this with 2 arduinos wired together? Context: I’m building a robot that will balance with reaction wheels while doing other tasks. I ...
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0answers
48 views

ESP32 + Attiny85 AC Dimmer

I am working on an AC Dimmer project using ESP32 and Attiny85. Note : I know ATtiny85 is overkill for this project, And it can be done without Attiny85, I have already done this using ESP32 alone. ...
0
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1answer
26 views

DS1337 with shared I2C pull-up

I have a project using an ATMEGA328P and a DS1337 RTC chip. The DS1337 is an 8 pin IC with VCC at pin 8 and GND at pin 4. According to the datasheet both pin 5 (SDA) and pin 6 (SCL) need an external ...
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1answer
36 views

Trying to use I2C accelerometer and SPI OLED

I'm trying to stream the data coming from my I2C MMA8452Q accelerometer to an Adafruit-based SSD1351 OLED RGB display that uses SPI via an Arduino UNO. When I run example code for the accelerometer I ...
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1answer
30 views

How to properly send bytes between RPI and Arduino over I2C while using ISR without IOerrors?

I have a I2C connection between an RPI 3B+ and Arduino Nano. I want to send a key and a corresponding value byte, and the arduino does something with that inside a timed ISR. Which works. But I get ...
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0answers
20 views

How do I read from a correct data address of LIDAR using Arduino in I2C?

I need to read the distance data from a lidar in I2C using an Arduino Nano. Currently, this is the code I've written. unsigned int readDistance() { unsigned int dist = 0 ; // LiDAR actually measured ...
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1answer
27 views

How to set 16x2 LCD I2C display backlight?

I have 16x2 LCD display with a I2C backpack. This is the library I am using https://drive.google.com/drive/folders/16_UqfwFm4VKWcdeJfDmHRV2Hj_IoaTai?usp=sharing So as given in the code below, by ...
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1answer
43 views

Digispark Rev.3 Kickstarter ATTiny85 using all 6 pins

i have some trouble to use i2c and the other pins at the same time. im tring to control the attiny over i2c with a arduino and the attiny should control a 28byj-48 stepmotor. i started to setup the ...
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1answer
112 views

Arduino with LCD Display does not reset/restart/start on connection to power

A friend and I have been working on an Arduino Sketch that does a request to a local API, parses that data and prints it out on an LCD Display. When we upload the sketch to the Arduino it does exaclty ...
2
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1answer
107 views

Convert float to byte, from Arduino to Raspberry Pi i2c

I'm trying to send the temperature value from the DHT sensor to a raspberry pi through I2C. Which is the best way to do it?. The temp value is a float, and I think I have to convert it to byte and ...
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0answers
22 views

avrdude: stk500_recv(): programmer is not responding Arduino LCD_I2C Upload problem ( port not found and …) [duplicate]

i have problem to upload the LCD I2c Example program to Arduino UNo. the code are shown below: //YWROBOT //Compatible with the Arduino IDE 1.0 //Library version:1.1 #include <Wire.h> #include &...
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1answer
55 views

Read from lux hangs in bright light

I am using VMEL6040 sensors and occasionally under bright light the read can hang, rather than using a wdt to recover I would like to ask some questions about the library. as for debugging the sensors ...
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0answers
42 views

Connecting esp8266 to spi/i2c video doorbell pins [closed]

The Vimar k40910 video doorbell exposes the following pins on its board: vin (5v) gnd sda scl clk data As far as I understand, pin 3-4 are for I2c while 5-6 are for SPI. Is there a way to connect to ...
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1answer
33 views

I2C pull up resistors and an I2C MUX

I have a rig with 5 light sensors on an I2C mux and I am wondering if I need only 1 pull-up resister set for the whole bus or one on each branch from the mux? Or should I remove all the pull-ups from ...
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0answers
30 views

How to name the temperature sensors instead of printing address using ds2482-100 and ds18b20 sensor- Help

I am using 10 ds18b20 Temperature sensors using with "DS2482-100" I2C board and Arduino so when I am getting the output like this:- "ROM = 28 46 04 1F 0D 00 00 74 96014B467FFF0A100A 25....
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1answer
49 views

Error in I2C Communication Between Arduino and Raspberry Pi

The code below sends data to Raspberry Pi every 20 millisecond. The code works fine but sometimes python throws an error. Why this is happening? Should I give more time between writeData? Error: > ...
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0answers
38 views

Unable to write, or read a sensor's registers. Do I have an error in my code?

I'm trying to write to register the change some settings for a sensor I'm using (BNO055) and then read the same register to verify if the changes are successful. However, the only value I'm able to ...
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1answer
35 views

Sending a struct over i2c

How would you send a struct from an i2c slave when requested by an i2c master? Slave Struct Respdonder Sketch (Seeeduino Xiao) #include <Wire.h> struct TransmitData { int a; int b; int c; ...
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0answers
27 views

How to connect multiple MPU-9250 IMU sensors to a single Arduino Uno? [duplicate]

The datasheet says the I2C bus limits itself to only two MPU-9250 sensors. How can I control multiple (>2) MPU-9250 through a single Arduino Uno? Is it possible to add another bus? Please, help.
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1answer
51 views

Is my BMA421 locked up?

I have been trying to set up the BMA421 motion sensor in a nrf52 based smart watch, using the datasheet for the BMA423, which has the same interface. I had got the sensor working well with the ...
1
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0answers
57 views

Prevent flicker - Lcd with I2C module?

I have a 16x2 LCD with a I2C interface, and a Esp8266 based NodeMCU. I Have an issue where the second line of the LCD is flickering, but somehow the first line does not flicker. Why does this happen ...
0
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1answer
95 views

How to change i2c address of Lidar Lite v3 using LidarLite library (Solved)

I have 2 Lidars which are Lidar Lite v3 and Lidar Lite v4, both of these sensor having the same i2c address. I'm trying to change my Lidar Lite v3's i2c address on arduino mega2560 using a function ...
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1answer
325 views

Multiple Wire.write() not working for Arduino Nano I2C

Code for Master #include <Wire.h> void setup() { Wire.begin(); Serial.begin(9600); } void loop() { Wire.beginTransmission(9); Wire.write('c'); Serial....
2
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1answer
47 views

Can't read data from registers using I2C

I am trying to read data from the registers 6, 7, 8 and 9 of the STC3100 (Data Sheet) using an arduino uno. I followed this tutorial: https://howtomechatronics.com/tutorials/arduino/how-i2c-...
-1
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2answers
49 views

Serial and I2C not working together

I have very peculier problem. When I run this code SSD1306 fails to initialize. Output at serial console is: 20:26:33.194 -> MPU6050 OLED demo 20:26:33.532 -> SSD1306 allocation failed #include &...
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1answer
45 views

How detect I2C errors with requestFrom()

I am going to use MCP23017 chips, and some of them will be cabled with a 1 meter max unshielded cable. I am expecting that certain transmissions may toss errors. So I want to tackle this problems by ...
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0answers
43 views

How to use pins for I2C that is used from other hardware?

I am using ESP32 CAM for one project and I have a sensor that is I2C connected to pins 21 and 22 (default I2C). The sensor is working fine until I turn on the camera. The camera uses this pins (21,22) ...
2
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2answers
41 views

TTGO TS I²C adress

I'm working on a project using TTGO TS wich communicate wih arduino via I²C protocole How can I find the adress of TTGO TS board used in I²C communication ?
2
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1answer
38 views

What's the time out of Wire.begin()?

Here's a schematic of my project: The purpose is to make laptop work as keyboard for desktop PC. Nano uses Serial.read() to get keystrokes from laptop and forwards key press and release data to ...
1
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1answer
74 views

Is it advisable to use Serial.write in an ISR when loop() routinely uses Serial.read?

I do not know much electronics. I have Nano v3 as I2C master, it reads 5-byte packets (of delimtted data) from PC's USB port, processes it and forwards it. I now need to implement a way to signal PC ...
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3answers
53 views

What is the difference between serial begin() and wire.setClock() for I2C communication?

I am a new Arduino IDE user and have a simple question below For I2C transmission speed setting, there are serial begin() and wire.setClock(). Some sample codes just use Serial.begin() without Wire....
2
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3answers
156 views

send values from arduino uno to wemos d1 r1

I have a weather project in which I have to measure the temperature and humidity ( dht22 sensor ), the pressure and other things and then show them in a local web page ( usings wemos d1 r1 ) in either ...
2
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0answers
60 views

SPI Arduino slave not recieving data correctly

Using an STM32L476RG Nucleo microcontroller board as the SPI master and an Arduino mega as a slave with pin 52 for SCLK, pin 53 for SS and pin 51 for MOSI on the Arduino. There is no issue with the ...
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0answers
58 views

Arduino Uno I2C two sensor connection Issues

I have been working on trying to get the MAXREFDES#117 PPG and the LIS3DH Accelerometer to run together. I am modifying the sample code found here to do so: https://github.com/...
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1answer
59 views

Arduino Nano Every I2C PORTMUX

Arduino Nano Every schematic informs us that we can use ATMega4809's pins PF03 and PF02 to communicate via I2C. ATMega4809 manual says in page 19 that in order to use those pins as I2C we need to use ...
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0answers
61 views

I need to make button to turn off my alarm on clock

well I get task to make school project alarm clock using arduino, xd as you can see im not very good at it i mean i know something but not everything so please can someone help me, i copied this code ...
0
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0answers
18 views

want to get data from one IMU and Arduino simultaneously using I2c communication

I want to get data from an other Arduino and IMU using I2c communication and wrote a code given below but it is not working for me , #include<Wire.h> // Define Slave I2C Address #define ...
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0answers
44 views

How to get a stable LED lighting without scintillation over I2C bus

I built an 8x8 led matrix using white 5mm LEDs. I drive the LEDs using the MCP23017 connected to an Arduino over the I2C bus. The wiring of the LEDs in the matrix is such that a row is made up of 8 ...
1
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1answer
52 views

Is it possible to change and save I2C address programatically?

I want to drive 3 i2c devices on a single i2c line. Is it possible to achieve this without using A0,A1,A2 pins? I thought the address of i2c devices should be programmatically changeable. 2 mcp23017 ...
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0answers
69 views

Using MPU6050 with ESP32 Cam- MPU Not Detected

Hi I'm trying to build a self balancing robot using my esp32 cam, but so far I haven't been able to setup my mpu6050 with it.I'm using the adafruit libraries with the given example sketches. The only ...
2
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1answer
250 views

Can't Turn Off Internal I2C Pull-Ups on ESP32

I've designed a custom ESP32 board around the WROVER-IE module. To keep power low, I'm using a GPIO-controlled high-side FET to turn off unused peripherals when in deep sleep mode. The issue: I've ...
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0answers
32 views

send command to Slave and receive response over I2c

so I have an Arduino mega as the master and an attiny84 as the slave the master can send a command S to the slave and the slave should respond with TRUE so here is my code: master: bool GetOnline(){ ...
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0answers
101 views

Reusing Digispark ATtiny85 micro-USB as 1-wire bus

I'm working on a project of my home plants irrigation/hydroponic system(not cannabis!)) just chilies and other eatables). Also I'm trying to recycle modules, wires and other projects' leftovers such ...
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2answers
84 views

I2C Devices Interference

I am currently trying to connect 3 I2C Devices to an Arduino Mega, as detailed in the fritzing sketch. The Sensors are: Max86150 PPG Sensor on a breakout board (5v), MLX90614 IR Temperature Sensor (3....
1
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1answer
38 views

Having trouble with MPU6050 and AFE4404 printing together, potential conflict?

I am having trouble getting the two sensors to work together. There are a total of four sensors connected to the Arduino, and while the MPU and AFE individually work fine with the other two sensors, ...
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0answers
55 views

I2C and SPI connection in the same-time [closed]

I want to make code between to devices , the communication between the I2C master to master , but in the sometime the one of the connect with other device SPI bus master to slave . how it work?

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