Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

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.

0
votes
1answer
19 views

compare char receive from Slave writer to Master reader with I2C

Im trying to send data from slave (writer) to master (reader) then compare it to declared 'char p[]' to turn on the lights but somehow i cant make it work. ////master reader #include <Wire.h&...
0
votes
1answer
215 views

I2C EEPROM “hangs” on endTransmission()

I am working on the 24LC256 EEPROM, wired as such, except 3.3v to the EEPROM, with 'scope clamped on SDA and SCL. I'm using an address scanner script with a few tweaks, 57600 baud, 10kOhm pullups, ...
0
votes
2answers
587 views

I2C communication between 2 Arduinos with updated wire library

I would like to enable communication between two Arduino 101. From what I have read, the best method is to use I2C using the wire library. However, it seems as though the newest Arduino IDE has an ...
0
votes
1answer
493 views

Arduino UNO inconsistent I2C register reading from ArduCam

I have an Arducam hooked up to an Arduino UNO. The code I am running looks like this: #include <Wire.h> #include <ArduCAM.h> #include <SPI.h> #include "memorysaver.h" const int CS ...
0
votes
2answers
49 views

How to get average of 16bit ADC readings?

I have an Adafruit ADS1115 analog-to-digital converter, configured in single ended mode. I want to average over 3 sensor readings to increase the reading stability. //initialize variables int16_t ...
3
votes
1answer
111 views

Accelerometer (I2C) and Fona Shield (software serial) won't work together

I am using a Fona 808 shield with an Arduino Uno and the LSM303 accelerometer. The accelerometer is connected via I2C and the Fona uses software serial. My project requires the accelerometer to be ...
0
votes
1answer
161 views

How to change speed of multiple servos acting at the same time with PCA9685 module?

I'm using the PCA9685 module with its Adafruit library. In my code I have one object of the servodriver class that has 14 channels (controlling 14 servos basically). void Positioning(){ ServoDriver....
0
votes
4answers
44 views

How can I hook up multiple MMA8451 accelerometers, (I2C protocol) using one Arduino Mega?

How can I hook up four (adafruit) MMA8451 accelerometers (using I2C protocol) using one Arduino Mega? What I'm confused about is I only have one SDA and SCL on the Arduino Mega obviously. So how can I ...
0
votes
2answers
36 views

HD44780 display incorrectly black-on-blue instead of white-on-blue

I have a generic HD44780 compatible 16x2 LCD display, with an already soldered on PCF8574 module. Its backlight is blue, and the characters are supposed to be white (on blue). It is connected to a ...
1
vote
2answers
584 views

I2C broadcast and reply on Arduino M0+

I am trying to set up several ATSAM-based AVR chips in a master/slave broadcasting arrangement. I want the master to be able to send a broadcast message to I2C address 0, and then for slaves to ...
0
votes
1answer
31 views

Is it possible to send a float Array over I2c

I have tried it several times myself but i never could send or receive it properly. I am asking myself if it is possible and if so could someone explain how? Cheers.
1
vote
1answer
192 views

Looking for light-weight Arduino OLED library that supports text and bitmaps

I'm trying to incorporate a screen into my Arduino code which is quite large already. The Adafruit SSD1306 library is overly large and has a lot of unnecessary things in it. I've found the ...
0
votes
0answers
41 views

Lost with Nano and i2c

I've been struggling with some code that was failing to "begin()" any devices on my i2c bus. I've uploaded a scanner program from arduino playground which lists the addresses of any i2c modules found. ...
1
vote
1answer
34 views

conflict with different i2c devices

I am trying to communicate with two i2c components using an arduino nano - some ADS1115s and some i2c flow sensors each connected to a different i2c multiplexer, but they seem to be conflicting. ...
2
votes
1answer
3k views

I2C libraries for ATTiny85?

I want to transmit I2C data, using a Digispark ATTiny85 board: http://digistump.com/products/1 http://digistump.com/wiki/digispark/tutorials/connecting I've found the following I2C libraries. Which ...
0
votes
2answers
254 views

Share I2C pins with other device when lacking GPIOs

We're Using ESP12E as our MCU and we have three functionality : SIM800 connected to TX(GPIO1), RX(GPIO3) Matrix Keypad connected to GPIOs: 14,13,2,10,0,4,5,16 GLCD connected to GPIOs: 15,12 And we ...
0
votes
1answer
104 views

Problem using Optiga Trust X I2C

Did someone ever used the Infineon Optiga Trust X module with Arduino using any I2C library ? Here is the technical documentation of the Trust X module. I'm trying to get the I2C_STATE register data ...
0
votes
1answer
2k views

OVF in serial monitor instead of data

I am currently working with two Arduinos and I'm trying to synchronize them. I want to get data from four LIS3DH accelerometers. The LIS3DH accelerometers are connected to the Arduino using I2C ...
0
votes
0answers
48 views

i2c code hanging - tried all connections

I'm trying to connect a TCA9548a breakout to my nano (also tried using an uno), but it can't recognise it - using the i2c scanner it just hangs on 'scanning...' I've tried everything suggested in ...
0
votes
1answer
66 views

How to connect MPU9250 with NodeMCU using SPI or I2C Slave?

I want to connect 3 MPU9250 sensors, but since there is just one I2C bus, so there are another 2 sensors I want to connect through SPI. Library used - https://github.com/bolderflight/MPU9250/blob/...
0
votes
0answers
28 views

Arduino IDE + Metro + I2C device (Grideye) + Code for Uno = weird results?

I have been working successfully with the arduino uno and a thermal camera device called grid eye. There is a board available at the popular suppliers of arduino addons. For the uno, the code looks ...
0
votes
1answer
483 views

Problem to display Ntp time on an oled using U8G2 lib

So I have this code to get ntp time and display it on serial port. But I want to display it on a 1.30 inch I2C oled with a SH1106 controller using the U8G2 library. The only problem is I don't know ...
0
votes
2answers
55 views

MPU-6050 with Arduino - postmortem

I'm working with MPU-6050 with Arduino Uno. I copied the code below from Arduino Playground - MPU6050. Code : // MPU-6050 Short Example Sketch // By Arduino User JohnChi // August 17, 2014 ...
0
votes
1answer
26 views

Arduino help adding a second mpu 6050 sensor my working code

Background information: I currently have this arduino code that uses one mpu 6050 sensor to get angles in the x, y, and z directions and then display them to the user nicely. Code can be found here ...
0
votes
1answer
1k views

Reading data from airspeed v3 eagle tree

I am trying to get values from this sensor Airspeed v3 from eagle tree but it seems my I2C is not working properly. I bought a module in third party mode and followed these instructions from the ...
0
votes
0answers
23 views

Having trouble reading directly from VEML6075 UV sensor from its registers(I2C)

I'm kinda new to Arduino and decided to dive deeper into learning abit more about Arduino; So i decided to grab a Sparkfun VEML6075 UV sensor and try to: 1) Initialise it 2) Take readings from it ...
0
votes
0answers
26 views

LCD not displaying any character with I2C or when used separately

I have an arduino uno and pin connection for I2C are - SDA --> A4 SCL --> A5 VCC --> 5v GND --> GND This the code i am uploading taken from the examples - #include <Wire.h> #...
1
vote
1answer
35 views

Wire.h missing - Failing to upload I2C 16x2 LCD sketch

I am total newbie in Arduino and for the last 3 days I am trying to figure this out. I would like to use an I2C display for a project. I have installed the LiquidCrystal_I2C, but when I try to upload ...
0
votes
1answer
23 views

Question on pin management using PCA9534PW IO Extender

There is an IO expander PCA9534PW, Arduino UNO. I don’t really understand how I can manage this expander using UNO over I2C. I found an example, but here is the reading mode. What I need: Set the ...
0
votes
1answer
66 views

Possible to connect 3 MPU9250 to Node MCU without multiplixer?

Is the idea of connecting AD0 pins of MPU9250 is still valid like the 2nd answer of this question? - How to change i2c address for mpu9250? I have connected 2 sensor as test. SCL & SDA of both ...
0
votes
1answer
79 views

What does the numbers behind lcd (0x27) means?

I can't seem to figure out what the numbers in after 0x27 means. I understand that 0x27 stands for I2C address and POSITIVE stands for the back light, but what does the other numbers mean? ...
3
votes
2answers
90 views

Need little bit of help on testing I2C sketch

I have this code I got from YouTube for communicating between two Arduinos. By typing 'R' manually into the serial monitor of the 'master' Arduino, the 'slave' will print "Success". I'm trying all ...
0
votes
0answers
44 views

How to interface Arduino with NXP PCA8561 LCD segment driver?

I've just bought few NXP PCA8561AHN LCD segment drivers to do some tests which unfortunately did not went as expected. I'm familiar with expanders and segment LED displays but LCDs seem to be way ...
1
vote
0answers
48 views

Is it possible to use I2C and SPI ons the same Clock line?

I'm trying to connect an I2C OLED display and an n RF24L01 WiFi module to an ATTiny85. But I only need 1 extra pin. Is it possible to use the same clock wire/pin for the I2C and SPI device? Maybe with ...
0
votes
0answers
40 views

SerializeJson not working when using softserial

IDE:1.8.8 Board:Arduino UNO When I use the code below, I get result of print like this. { "result": [ { "ID": "01", "Value": [ "2", "1", "13" ] } ] } But when I use SoftwareSerial and in the setup ...
0
votes
2answers
39 views

Connecting multiple MAX30100/30102 via I2C

I want to connect multiple (up to 4) MAX30100 or MAX30102 oximeter sensors to an Arduino via I2c. But I could not find a solution to change/assign the I2C address. implementing-pulse-oximeter-using-...
0
votes
1answer
41 views

I2C potentiometer mess

I bought a few MCP4651 dual 8 bit I2C pots for a project. After browsing the arduino libraries and finding nothing,"No big deal" I thought to myself ... I've already written I2C libraries for other ...
0
votes
1answer
2k views

MPU-9250 IMU on SPI, external sensor or magnetometer using I2C master

I'm trying (for sport...) to use an MPU-9250 in SPI mode as it should be faster, and wasn't able to talk to the embedded magnetometer in my code. I've gone through the documentation (RM-MPU-9250A-00 ...
0
votes
0answers
36 views

What is the difference between the digital temperature sensors SHT31 and DHT11 or DHT12?

I am looking for a digital temperature sensor with I2C interface. I found the SHT31 and the DHT12 (compatible to DHT11). Both also include humidity sensors. And I found libraries for both of them. ...
0
votes
0answers
38 views

Problem I²C Communication between Arduinos

My Problem seems to be that my I²C slave randomly disconnects. I have an Arduino Due communicating with a Arduino Chestnut board (bought hardware). I now measure data with the Due and then send the ...
0
votes
1answer
49 views

ATTiny85 I2C connection with Arduino Nano

I am trying to send and receive data using I2C between an Arduino Nano and an ATTiny85. The ATTiny is mounted on this board: Link I've tried to reach the slave with the simple I2C scanner, but I don'...
4
votes
2answers
599 views

Crash when datalogging MPU-6050 to SD card

On an Arduino Pro Mini, I'm using Jeff Rowberg's stuff in i2cdevlib to read from the MPU6050, and using SdFat to write data to an SD card. Each part in isolation is fine, but when both DAQ and logging ...
4
votes
2answers
43k views

Sending and receiving different types of data via I2C in Arduino

I have found a few good tutorials on how to send and receive data via I2C in connected arduinos. My limitation is now how to transmit different types of data like for instance, long, float, etc. Right ...
2
votes
2answers
97 views

Risks when commanding multiple chips with same address via I2C

I know that I2C devices are supposed to have unique addresses when used. What if I still use multiple devices with the same address, what can go wrong? Let me describe the situation: I have multiple ...
0
votes
0answers
39 views

Buffer to string

I'm a bit of a noob, so excuse if this is more obvious to me than to you. I want to convert a u16 to a string. The u16 is the data coming in from the sensor. I need it as a string, or anything else ...
3
votes
2answers
398 views

ATtiny85 LM75 I2C

I would like to read temperature from a LM75 using the ATtiny85 running a core by SpenceKonde and utilizing the TinyWireM library. My Logic Analyzer does not pick up any I2C communication, when I ...
0
votes
1answer
123 views

Issues with I2C and Wire.Available()

I am working on a project which requires communication from an Arduino Due (Master) and an FDC2214Q1 C to D IC (Slave), but there is some variability as to whether the code works or not depending on ...
0
votes
1answer
50 views

Same output on displays with different I2C-addresses (AdaFruit library, ESP32)

I've got two displays hooked up to a ESP32 via I2C and I'm using the AdaFruit library. All handling display output is packed in a own library. As I was testing I only had one display set up and ...
0
votes
1answer
165 views

Slow refresh rate on I2C OLED screen

I'm trying to create a small handheld console with 6 buttons and an I2C 0.96" OLED display: https://imgur.com/a/AKiRMWN The directional buttons use the analog pin and different resistors technique to ...
0
votes
0answers
40 views

Bit Bang I2C with port manipulation on AtTiny84: new pinout doesn't work

So I am trying to understand bit banging and port operations. I'm developing a breakout board with an ADXL343 IMU read by an AtTiny44 via i2c. I adapted this code from MIT's How To Make Almost ...