7
votes
Multiple Wire.write() not working for Arduino Nano I2C
Important information: Wire.write() does NOT send anything over the I2C lines. It just puts the data into the libraries internal buffer. The actual transmission is then done by Wire.endTransmission().
...
- 16.6k
7
votes
Accepted
Bi-directional UART communication on single data wire, possible?
You can have bidirectional communication over a single wire by using
open-collector outputs. For this, you could add a circuit like this
on each side of the link:
simulate this circuit – ...
- 45.2k
6
votes
Accepted
Is the arduino hackable when using communication shields?
You should be pretty safe, at least as long as your code handles the
incoming data properly.
When you upload a new sketch through USB, the USB-to-serial interface
uses the Arduino pins TX0, RX0 and ...
- 45.2k
5
votes
Accepted
Why is the IDE not able to find the board despite it being clearly seen and selected?
The SAMD boards connect to computer over native USB support of the MCU. The handling of the USB is done by Arduino core functions linked at build to your sketch.
A consequence of using the native USB ...
- 18.3k
5
votes
Accepted
How to send multiple data over serial in one byte?
You should learn how to use bitwise operators. These are needed to do what you want.
We can save the state of each switch in one bit each. For this we first define our global variable that will hold ...
- 16.6k
4
votes
Hacking old car dvd monitors with arduino
I realize this is an ancient question, but just in case someone else has one of these things, I'll share what I know. I have one of these Sharp LCDs that I typically use as a monitor for a Commodore ...
- 41
4
votes
Accepted
Communicating to arduino as fast as real-time
Going over USB will add about a millisecond of jitter to your data in both the sensing and command directions. Using a part with direct USB rather than then needing to go through a serial link from ...
- 5,411
4
votes
Accepted
I change ESP8266 baudrate and now it doesn't work
Have you tried setting the web editor's baud rate to both the old and the new values? I ask because the CIOBAUD command has been obsolete for a while now so, depending on the age of your device, it ...
- 15.4k
4
votes
Missing character when introducing delay in the code
If serial data is coming in, and your code is doing a delay, the incoming data is stored in a buffer (of 64 bytes). But if you wait too long, the buffer will fill-up. Once it's full, any further ...
- 11.3k
4
votes
How to automatically reset the NRF24L01 module
This is a known problem with those chips (especially Chinese clones). It is caused when a chip gets stuck in TX mode waiting for an ACK that never arrives back.
The chips don't have a "reset", but ...
- 106k
4
votes
Accepted
Sending data struct with 2 int fields from Arduino to Raspberry via NRF24L01
Your problem is that you are communicating between an 8-bit and a 32-bit architecture.
On an 8-bit architecture int is 16 bits. On a 32-bit it's 32 bits. Why the difference? Because "it is". ...
- 106k
4
votes
Accepted
how can I accurately recieve potentiometer values over the USB port?
There are a few issues at play here. One is that the Arduino
resets every time you open the serial connection on the PC side. You can
prevent this by putting a 1 µF (or more) capacitor between 5V and
...
- 45.2k
4
votes
Accepted
Arduino Timer Drift Issue
Any fee-running clock will drift. Worse yet: its drift rate will not be
constant. This is a fact of life, and there is nothing you can do about
it. There is no software solution, although your ...
- 45.2k
3
votes
Accepted
Arduinos using I2C reading integers wrong
wire.write(n) sends a single byte of value n
150 decimal = 96 Hex
300 decimal = 012C Hex ...so is 2 bytes, and is truncated to one byte of value 2C Hex.
2C Hex = 44 decimal
Send a single byte! ...
- 269
3
votes
Does the SIM800L works in the US?
I wanted to post an update in April 2021 on the status of this question.
The SIM800L will work in the US, but T-Mobile is the only carrier that it can interface with. AT&T shut down its compatible ...
- 131
3
votes
Accepted
Problem communicating between arduino UNO R3 and Mega 2560 via MAX485
You have forgotten to add mySerial.flush().
mySerial.flush() waits for the transmission of outgoing serial data to complete.
Add it right after you have sent the data and want to change the DE pin ...
- 44
3
votes
Accepted
Arduino ModBus RTU master communication with Power Meter problem
I have made it. Now it is working. I only checks A & B cables (tried a new one) and change address of register from 5000 to 0x5000 and now it works. I thought that this library already give 0x ...
- 63
3
votes
Accepted
Why do COM port numbers between Arduino and Processing not match?
If you print out portName it should be COM4 it seems you must have 3 COM ports on your machine otherwise you would use index 0; Serial.List() appears to return an array or list which you are taking ...
- 628
3
votes
Connecting (SD or HD) TV screen to Arduino
I'm just going to post things that I found thanks to comment by Juraj.
"TV Text" library - PAL, SECAM, NTSC
"VGAX" library - VGA
And with large dedication to everyone who wrote that "it's impossible" ...
- 1,312
3
votes
Getting issues while using SoftwareSerial
SoftwareSerial only works on a few select GPIO pins on the Mega. Specifically those pins that have PCINT on them.
But that is irrelevant. There is no reason to use SoftwareSerial on a Mega except in ...
- 106k
3
votes
Serial Commmunication between two arduino
The problem is that a serial connection usually connects two devices, in your case it's three (sensor arduino, receiving arduino and your pc).
To get around this you have to use an additional ...
- 1,878
3
votes
Connecting an Arduino Nano to a Raspberry Pi Zero
You can connect via:
UART
I2C
SPI
All are available on the Pi's GPIO header and on the Arduino. You will of course need logic level translation for a 5V Arduino.
Using UART is probably simplest for ...
- 106k
3
votes
How can I display text on OLED?
Just guessing but looks to me like you read the CAN message and print it character by character to the Serial console but you don't save those characters in a buffer as you get them from CAN.read().
...
- 170
3
votes
Accepted
Sending minimal data between two Arduinos far away from each other
RS-485 is best (you can buy some modules for this from Adafruit, Amazon, eBay, etc), but you can use the built-in hardware RS-232 serial UARTs from each on pins 0 and 1 so long as the baud rate is ...
- 1,385
3
votes
Using several Arduinos simultaneously
Among all the options mentioned, using a master/slave should be the last resort, especially when you are new to embedded programming or Arduino, it is not only more complicate but also more expensive ...
- 1,978
3
votes
Accepted
No response from instrument via serial communication
The Sparkfun RS232 shifter is not a great device. It relies on whatever it's connected to (on the 9-pin port) providing the negative rail for the EIA-232 voltage levels.
That's fine when you connect ...
- 106k
3
votes
Bi-directional UART communication on single data wire, possible?
This question likely suffers from the X Y problem. Where the question (about software) and possible answer (centered on hardware) do not approach the solution using the same methods.
The question is ...
- 7,513
3
votes
Arduino Nano: Send a few bytes over Serial with as little delay as possible
"Slowing down to speed up". - a Chinese proverb
The problem is with your python code. Not sure what your computer's operating system is, but if you are using Mac or Linux, if you run top ...
- 1,978
3
votes
Accepted
How to make an Arduino act reliably as an SPI slave?
Your problem here is timing. I tried your setup, and found that I did indeed get occasional errors at 125 kHz. Disabling Timer 0 (as suggested by Chrisl) fixed that:
power_timer0_disable();
But ...
- 38.9k
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