I need advice on setting up a web server on a Raspberry Pi that can communicate with the serial port.
Im leaning towards doing this i php/python/nodejs or c if necessary.
Requirements:
1. incoming data on serial port => update webpage through web sockets
2. some event on webpage => send data to serial port
A continuous loop to check for serial data will be heavy on the cpu. Is there any way to get an event on incoming serial data and then read it? Found https://github.com/voodootikigod/node-serialport that has an on data event. Is that a good option?
Can the serial communication be handled by the web server or will i have to create a service?
Best approach for me was to use node.js and https://github.com/voodootikigod/node-serialport in combination with socker.io. That gives men an event when serial data received that can be communicated via socket.
Related
I'm building a project where I use 2 ESP8266 and 1 ESP32 devices, where I collect data with sensors on ESP8266's and send those gathered data to ESP32. Then, this ESP32 device sends an HTTP request (w/ HTTPClient) to my NodeJS Web Server, with the data received, which will eventually be processed there and saved to the database.
I'm having a problem though; when I use some mock data, and use only ESP32 without ESP-NOW and any other connection with other devices, I get status code 200, which indicates that my HTTP Request is sent succesfully. And when I use ESP-NOW to establish conenction between ESP devices, and not send any HTTP Request, I can successfully send and receive data.
However, when I use ESP-NOW to send and receive data, and send the data using HTTPClient request to my Web server on ESP32, I get status code -1 (refused connection). I couldn't find any other issues regarding this topic, so I figured I might ask for some help.
I have also used painlessmesh library to send/receive data between ESP devices, but that gave me the same exact issue. I'm using Wifi mode STA on my ESP32 device, which I connect it to my router to connect to the internet.
Thanks in advance for any help and support.
You cannot use ESP-NOW and WiFi in parallel at the same time; it's either-or. Exception: if you use the same channel for both (may not be possible)!
Option 1
You can alternate between the two protocols. So, as soon as the ESP-NOW transmissions from node 1 has completed (data fully received) you turn off ESP-NOW, connect to WiFi, publish via MQTT and then reverse. Needless to say that while your ESP32 is on WiFi you cannot receive data via ESP-NOW from either node 1 or node 2.
Option 2
Use some sort of gateway between ESP-NOW and WiFi. This product for example contains two ESP32 (connected over UART), one for ESP-NOW, one for WiFi: https://thingpulse.com/product/espgateway/. Disclaimer: I am a ThingPulse co-founder.
It is possible to run a web server and esp_now in the same esp32. Check my code here https://github.com/Servayejc/esp_now_web_server for the server
https://github.com/Servayejc/esp_now_web_server for the sender
This code make also automatic pairing of the nodes of esp_now.
This code is based on randomnerdtutorial…
how the bellow connection can be done , what the protocol that must be used to send bytes from computer through it's serial WiFi and receive the bytes in Arduino using ESP8266-01 WiFi Serial Transceiver Module.
computer AND esp8266 WITH arduino
It depends on what you want to accomplish, and what roles you want the computer and the arduino/esp combi to play. You can put the ESP in station or access point mode (or mixed), and have it talk to the arduino via the serial interface. The communication with the PC will indeed go via wifi/tcp protocol, but depending on your specific requirements you will have to decide one the roles. Then you can make the ESP a web client or a web server, mainly depending on the direction of the flow of information.
I assume you want to query the Arduino from the PC, in which you can send a HTTP/GET request from the PC to a simple web server on the ESP.
There are various examples in the Arduino examples that do just that to give you a start, available when you install the ESP library in the Arduino IDE, see: https://github.com/esp8266/Arduino
HTH
I am trying to send sensor data from an Arduino UNO to my server running on a local wifi network. My server is an HTTP server run on NodeJS.
I need the Arduino to send data to the server as fast as possible as fast as a request every 100~250ms. The code from the WiFiClientRepeating example sends data to the server properly every second or so. If I reduce the frequency to something lower or equal to 500ms, the server does not seem to receive anything.
Are there any limitations to how many requests there can be done in a set period of time?
EDIT: I am using the official Arduino WiFi Shield.
I have the following scenario.
I have a LAN and more than one GSM modems are connected to a server. I want to receive incoming call on GSM modem and transfer this call to other PC on the network. Is it possible? Can anyone give me an idea to achieve this?
You cannot 'transfer the call'.
You will have to receive the calls from each modem on the server only, then you can implement something like a VOIP/sound streaming system by which you can simply send and receive the audio between server and client(s).
I've been trying to do TCP communication using my Wavecom Fastrack modem. What I want to achieve is make the modem connect to a specified TCP server port to enable me to transfer data to and from the server. I found some information on than in the user's guide.
Basing on the information you can find on page 66 I created an application that opens the serial port to which the modem is connected and writes the following AT commands:
AT+WIPCFG=1 //start IP stack
AT+WIPBR=1,6 //open GPRS bearer
AT+WIPBR=2,6,11,"APN" //set APN of GPRS bearer
AT+WIPBR=2,6,0 //username
AT+WIPBR=2,6,1 //password
AT+WIPBR=4,6,0 //start GPRS bearer
AT+WIPCREATE=2,1,"server_ip_address",server_port //create a TCP client on port "server_port"
AT+WIPDATA=2,1,1 //switch do data exchange mode
This is exactly what the user's guide says. After the last command is sent to the modem, the device switches to data exchange mode and from then on everything what is written to the serial port opened by my application should be received by the server and everything the server sends should appear in the input buffer of that port.
The thing is that I did not manage to maintain stable bidirectional communication between the server and my modem. When I write some data to the serial port (only a few bytes), it takes a lot of time before the data appears on the server's side and in many cases the data does not reach the server at all.
I performed a few tests writing about 100 bytes to the serial port at once. Logging the data received by my server application I noticed that the first piece of data (8-35 bytes) is received after a second or two. The rest of the data appears in 2-5 seconds (either as a whole or in pieces of the said size) or does not appear at all.
I do not know where to look for the reason of that behaviour. Did I use wrong AT commands to switch the modem to TCP client mode? I can't believe the communication may be so slow and unstable.
Any advice will be appreciated. Thank you in advance.
what OS are you running? Windows does a pretty good job of hiding the messy details of communicating with the GPRS modem, all you have to do is create a new dial-up connection. To establish the connection you can make a call to the Win32 RasDial function. Once connected, you can use standard sockets to transfer data on a TCP port.
i have been using wavecomm modem for 2 years now.As far as i know from my experience is that if you are able to send some of the data then you can send all of the data.
the problem might be in the listening application which receives the data on the server side.
It could be that it is unable to deal with the amount of data that you are trying to send.
try sending the same data in smaller busts
with some delay in between them,then you might receive all data intact.