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Unanswered Questions

1,447 questions with no upvoted or accepted answers
6 votes
1 answer
2k views

Ultrasonic Flowmeter Using TDC-GP22 and Arduino Uno

I'm working on a project of Ultrasonic Flow Meter with TDC-GP22 using Arduino UNO. I used the library of leokoppel In my code,the configurations of the registers are copied from the Application Note ...
5 votes
0 answers
361 views

SPI between Master arduino and Slave arduino

How can I send the string from Slave SPI to Master SPI? I want to write code in Bare Metal. The problem which I am facing is I can't make out what will be my blocking function in Master SPI code when ...
5 votes
0 answers
2k views

Modbus TCP/IP using Arduino uno and ENC28J60 module

I have this project where I need a modbus tcp server that will host a series of sensor data for other modbus client devices to read. I use this Library by Andresoarmento This is the code i am using ...
5 votes
0 answers
419 views

DHT22 reading weird values

I just hooked up a DHT22 I had laying around in a parts drawer to test something and it is giving out some crazy wrong values, I am running the adafruit library's unified example and this is the ...
4 votes
2 answers
732 views

Bluetooth communication not working with DC power but works with USB power?

I am running an HM-10 Bluetooth Low Energy (BLE) module to transmit serial data (using SoftwareSerial) from an analog sensor onboard my Arduino Uno to a serial terminal app on my Android phone. When I ...
4 votes
0 answers
343 views

Is Arduino WiFi101 library fully compatible with Arduino MKR1000 with WiFi HW?

Will all the classes in this library work with the MKR1000 with wifi hardware? The guide mentions "wifi shield". So, does the library work exactly the same with the Arduino MKR100 (with the onboard ...
4 votes
0 answers
737 views

Nordic nRf905 (433MHZ) with arduino receive garbage data

I am interface Arduino with nRf905 in receive mode use 433 MHZ. I Have follow this link http://www.electrodragon.com/w/NRF905_Transceiver_433MHz-Wireless_Module. And for transmitter, I am use RF-...
4 votes
0 answers
206 views

How to filter out "jumpy" readings sent using Bluetooth

I'm using App Inventor to continuously send orientation values (as strings) to my Arduino, which are read using Serial.parseInt(). Using simple IF statements (if value > threshold), I'm trying to turn ...
4 votes
0 answers
650 views

RFID Code (and setup) works on an UNO but not on the Yun

We're using two RDM6300 RFID readers for this, and the code works when plugged into an UNO, but not when connected to the Yun. We have one of the rfids plugged into the rx pin (0 on the digital side) ...
3 votes
0 answers
74 views

Why RTU bridge timeout even though answer is received?

I'm testing the following code as a bridge between https://sourceforge.net/projects/qmodmaster/ and https://pypi.org/project/pyModSlave/. As hardware, I'm using a NodeMCU 1.0 and a USB/TTL converter. ...
3 votes
1 answer
151 views

Arduino R3 Uno Clone - When barrel plug connected there is 5V on USB. Why?

I have been using Arudino Megas for some projects and never had this problem. Simply enough - I am powering arduino with 12V in via barrel and take power out via VIN to 12V low very low current small ...
3 votes
0 answers
280 views

Sim800l doesn't respond to AT commands

My SIM800L doesn't respond to AT commands. The serial monitor is simply blank. And the led blinks every 3 seconds which means it is connected to a network I power it through an LM2596 buck down ...
3 votes
0 answers
191 views

Grove LCD display not working with arduino rev 2 wifi (Unknown error at address 0x3E)

I am trying to connect Grove 16x2 LCD (White on Blue) to my Arduino uno rev 2 wifi. So far, I've tried hd44780 library's ioClass examples, but nothing worked. I've then decided to scan ports and when ...
3 votes
0 answers
608 views

PCA9685 - Hardware problem with diode?

I'm working on a project, where I need to run several high-torque servos. For that I bought come of these PCA9685 boards. I hooked everything up with my arduino and connected an external 5V - max 3A ...
3 votes
0 answers
211 views

220v lightbulb gradual dimmer

I am trying to turn my incandescent bulb gradually,say its brightness should go from zero to 100% in 10 mins. In doing so I found the following code and it works well but it's not as gradual as I ...

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