ESP8266 "AT" shows no response - serial-port

I tried to communicate with my ESP8266 over a serial connection but i don't receive any response from the device.
What is working: Flashing works and i can get the Chip ID and MAC address (using esptool).
Wiring is done like shown here
Power comes from an external stable 3,3 V source. No VCC connection on the USB-Serial converter side (but they share a common GND connection). Changing the Baud-Rate makes no difference. I tried screen, minicom and Arduino's Serial Monitor. I can send "AT" but the response is empty. The monitor's window is full of rubbish when i grab the MAC address over esptool.
I'm pretty much out of ideas at the moment! What else can I try?

Related

HC-05 Bluetooth module help, can not recieive data

I am writing some code for my arduino nano and I am using an HC-05 module for wireless transfer of data. I am sending my data as such. This is from the serial monitor, using a usb and regular print statements. I want to be able to recieve this data, and the store it in a csv (I know how to store incoming data). I need help recieveing my data.
22:17:46.765 -> =============================================================
22:17:47.770 -> Sleep timer:242
22:17:47.770 -> Light Sleep: 0 Deep Sleep: 0
22:17:47.805 -> Total Light Sleep: 0 Total Deep Sleep: 0
22:17:47.838 -> Total Sleep: 0
22:17:47.871 -> =============================================================
For some reason, when I connect my HC-05 to my windows desktop via bluetooth, and open a serial monitor in com ports 3 or 4, I get no read out.
My ports
I have it set up as so.
My wireless intialization
Then, I use
MySerial.print()
, to send data, yet I get no output, same thing occurs if I use
Serial.print()
.
I tried getting a new HC-05 module, Switched out all the hardware, tried different prints including Serial and MySerial. I though i could get an output.
Python code I tried to use python to extract the data, yet I get no output. I am not sure what to do here.
Not enough information, but I'll answer biased on the experience I've had with these modules.
Here are instructions for changing or verifying the baud rate on the module:
https://www.instructables.com/Change-the-Baud-Rate-of-HC-05-Bluetooth-Module-Usi/
For my module, I could just send AT commands by default without putting it into AT mode. Send 'AT' to the module and it should respond with "OK".
It helps a ton if you have an ftdi cable for troubleshooting. Connect the ftdi to the HC-05, verify the baud rate and that the HC-05 is responding, open a serial monitor for the bluetooth on the pc and one for the ftdi cable. Try sending data back and forth. Also, be 100% sure you're using the correct com port for your bluetooth by unpairing and repairing and see which com port shows up.
It actually is possible to use the HC-05 for programming the Arduino as well if you set the baud rate to 115200 and figure out a way to hit reset on the Arduino as soon as the bluetooth connects(status/state goes solid). I used an ATTiny for that, but you could just use a pin on the nano connected to reset and another pin to monitor the "state" pin which is connected to the led on the HC-05. That way you can have wireless data and wireless programming if you wanted that.

XBee is suddenly not receiving anything after I updated Destination mac address

Hello. I am using XBee for serial communication. I majorly use it from python.
However, after I changed the destination mac address of the XBee, it suddenly does not receive anything. When I send something, the TXD led blinks, however, RXD led never blinks.
My first guess was checking everything in the XCTU software. I re-installed firmware (newest) and I rosetted the destination mac address and then I checked whether it is using AT mode. (It is using AT (transparent mode.)
If my knowledge is correct, it should show something in the console log to the other side if I type something there. Is there any suggestions to solve this?

ESP8266 connection to a Arduino Nano

I am trying to connect a WiFi module (ESP8266) to a "funduino" development board (Arduino Nano) but I have no success. Since I tried so much schematics I've found on the internet about the connection between them two, I kindly ask here if is anyone who succeed in "pairing" this two devices.
I am asking for the schematic and a functional source code.
Regards
The ESP-01 by default comes with nonOS SDK bootloader that communicated via AT commands, you can find the complete command set from Expressif here. This is designed for an MCU (like Arduino Nano) to use it purely as an WiFi module rather than using it as a stand-alone MCU (for which it will require NodeMCU SDK).
If you ever upload an Arduino sketch up to the ESP-01, it will erase the AT Command firmware.
Assuming your ESP-01 is still having the AT Command firmware. What #Ben provided is a sketch that allows you to type AT commands via the Serial Monitor to internact with the ESP-01, it is manual, and good for testing if ESP-01 is working (you type AT and press return on Serial Monitor, the ESP-01 will ack with Ok) but not practical as a real application. The minimum commands required to established an WiFi connection with ESP-01 is listed below.
AT+CIPMUX=1 - Enable single (0) or multiple connection (1) to the web server.
Multiple connection is a good option if you are repeatedly sending
out or reading data from the Internet.
AT+CWMODE=3 - Set WiFi mode: 1 is station mode (ESP8266 is client), 2 is AP mode
(ESP8266 acts like a WiFi router where your phone or PC can connect),
3 is AP+station mode (make the ESP8266 do both)
AT+CWJAP=“<your-ssid>”,”<your-pw>” - Connect to your WiFi. Provide your SSID name
and password inside the double qoutes.
AT+CIFSR - This returns the IP address of the module, indicating that it has
successfully connected to your WiFi router.
Once the WiFi connection is established, you can further communicate with the ESP-01 via the connection, like accessing a website for example:
AT+CIPSTART=0,"TCP", "www.example.com","80” - Start TCP or UDP connection. The
0 is the id of the connection.
AT+CIPSEND=0,16 - Command to tell the module data is ready to be sent. 0 is the
connection id, and 16 is the length of the data to be sent.
After this command, the ESP8266 will reply with the “>”
character to tell us that it will be waiting for the data to be
sent. If successful, the module will reply with “SEND OK”
GET / HTTP/1.1 - Send the http header, and other data, etc...
You can write your own sketch to automate those AT commands for interacting with with ESP-01 once you understand the AT commands required for establish a WiFi connection.
Here are two resources that I personally found extremely useful for doing more than connecting to WiFi.
STM32-ESP-01 Web Server - although this is for interfacing with STM32, the main difference is the pin assignment, so you should be able to port to Arduino easily.
MQTT via ESP-01
As for hardware interface, please noted that what #Ben provided is correct in principle, but you need to be aware that the ESP-01(ESP8266 to be precise) is a 3V3 MCU, so the connection is depended on what kind of host board you are using. If you are using Arduino Uno/Nano, both are having a 5V MCU, you will need a voltage divider (two resistors to drop the voltage to 3v3 before connecting to ESP-01) or a level shifter chip at least for the ESP-01 Rx pin to avoid the potential damage to the ESP-01.

Arduino & ESP8266 - strange characters in response

I'm working on an Arduino Uno + ESP8266 project.
I try to use them as a web server on Wi-Fi network to control a motor that connects to Arduino - basically a trigger system that receives signals via Wi-Fi. Currently, I've successfully connected ESP8266 to my access point by sending AT commands from Arduino. Another client on the same network can statically access ESP8266's assigned IP address.
However, when I try to catch some HTTP queries (I want to use them as conditions to control the motor) I occasionally encountered the non-ASCII characters in HTTP request. I use serial comm to debug, please look at the screenshot in the link below:
Arduino - Computer serial communication for debugging
The line ",519:POST ..." should contain a complete number following "/?", but there's some strange characters instead. So I cannot determine the input data to control motor. Once in a blue moon, the expected format of request shows up as follows:
The correct data received
There's no issue with the HTTP response part, even though I got the uninterpretable request, I can still send the JSON error message back to client.
Attempt Note:
The Arduino uses different serial ports to talk to computer and ESP8266. Since the connection can be established, and the data being sent, I believe that the baud rate is simply correct on both side. (115200 for ESP8266, 9600 for computer - also tried 115200 for both and got the same result)
I use V3.3 from Arduino as power source for ESP8266. But I also use voltage regulator to smooth out the current as many people suggest that. The problem still remains.
I'm struggled with this issue for a few days, just want to know if anybody had the similar experience, or could give some clue for the next step.
After a considerable effort to stabilize the circuit, I switched to NodeMCU and got the system working perfectly. I assume that ESP8266 alone is somehow not robust enough without other components, which I unfortunately have no knowledge on.
So I'd like to close this thread with a short recommendation for anybody struggling with the same issue to switch to NodeMCU (which would replace both Arduino and ESP8266); if that could support the requirement.

What is the cause of "stk500_getsync(): not in sync: resp=0x00" in Arduino

I was using Arduino Uno to build a robot, but suddenly this error (stk500_getsync(): not in sync: resp=0x00) occurred. I tried a lot, searched on the net, to fix this error, but no solution worked for me. At last I bough 2 new Arduinos. But each of those 2 Arduinos ran few days correctly and after a few days gave the same error.
I was, and am, unable to find what causes this error. Can anyone kindly tell what could be the mistake I may be doing?
This has happened when the COM port is not correctly selected. Determine the COM port used to communicate with Arduino and set in in the IDE, then recompile the sketch.
I just found the reason from this link
of this error.
There are a TON of pages out there on how to solve this error. The problem is none of them worked for me. The typical solutions range from not having the correct serial port or correct Arduino model board selected under the Tools menu in the Arduino software, to not having a driver (or the correct driver) loaded.
However, the frustating part for me is I KNEW I had the correct serial port and board and driver selected because I was getting output from a sketch scrolling in the Serial Monitor window via a USB connection.
The fix? DISCONNECT ANY WIRES going to pin 0 (RX) while you do the upload. The sketch upload function uses the RX pin.
NOTE: You also need to disconnect any wires going to pin 0 (RX) if you have a sketch with a Serial.read() or Serial.peek() statement, and you want to use the Serial Monitor input field (as shown using the '752' in the example below) to feed data into the running sketch. If you don't disconnect pin 0 it will appear as if your data was entered into your sketch but nothing will happen because the data never truly gets input.
It's looks like there is no connection between PC and Arduino. Possible reasons: Something wrong with USB port OR driver, USB wire, ATMega16 controller, ATMega328 UART or bootloader. First, try to check, if data from Serial Port reaches Arduino. Pull ATMEGA from socket, short-circuit pins RX and TX on Arduino board (pins 0 and 1), and send some data from PC. You should receive exactly same string, as you sent. Also you should se RX TX LED's blinking. If you can't see data back, check if serial port you are using are actually exist in device manager, try to play with it's settings (speed, port numer), try to use another USB port and cable, etc.
I was having the same issue. But for me no led was lighting up on connection and the error observed was the same as yours. I fixed this by changing jumper pin configuration from ext to usb . You can try the same settings by altering the jumper pins between power jack and usb jack.

Resources