I have an ESP32 board, with Micropython installed properly, and connecting to local the internet.
Since it have to do a scheduled jobs- its clock need to be synced. After boot it get a generic date 1/1/2000.
How can Micropython updates int clock using ntp.pool.org or other?
Guy
From this post on the Micropython forum:
There is primitive NTP support in the ESP32 port (borrowed from the
ESP8266 port). In short:
import ntptime
ntptime.settime() # Synchronise the system time using NTP
Caveat: There is no timezone support so the system time will be set to
UTC.
From this discussion, you need to make sure you have an active internet connection before trying to set the time, and you should expect to get occasional timeout errors and handle these appropriately.
For reference the source of the ntptime module is here
You can get a DS3231 RTC. I’m currently using one and it works great.
Related
I'm building an small project in which I'd like to send information from a master HC-05 bluetooth module to an slave one (both of them connected to different pi pico's), I've already synced them following Bluetooth HC-05 master-slave configuration using CircuitPython tutorial, I've finished the set up and now both modules (master and slave) seem to be properly connected, now the problem is that I don't know how to send data from one to the other.
All the tutorials that I've found that imply bluetooth communication seem to do it from a mobile Android app to the slave module, but what I'd like to do is to read data from an analog joystick with one pi pico and send it to through my master HC-05 the slave module (which would be connected to another pico) and then control an electric motor with this received data.
As I understand, the configuration process was finished in CircuitPython but this DOES NOT obligate me to continue with CircuitPython, I mean, I could do my implementation with microPython for example as Circuit Python was used only for the configuration process, is this correct?
My main question is, what is the library/process I could use to send data from master module to slave module?
Pd: I know there is a Raspberry Stack Exchange site but I posted my question here for visibility and also it is related to software too!.
Summary:
I am guessing that the issue here is something to do with how Windows and Linux handle TCP connections, or sockets, but I have no idea what it is. I'm initiating a TCP connection to a piece of custom hardware that someone else has developed and I am trying to understand its behaviour. In doing so, I've created a .Net core 2.2 application; run on a Windows system, I can initiate the connection successfully, but on Linux (latest Raspbian), I cannot.
It appears that it may be because Linux systems do not try to retry/retransmit a SYN after a RST, whereas Windows ones do - and this behaviour seems key to how this peculiar piece of hardware works..
Background:
We have a black box piece of hardware that can be controlled and queried over a network, by using a manufacturer-supplied Windows application. Data is unencrypted and requires no authentication to connect to it and the application has some other issues. Ultimately, we want to be able to relay data from it to another system, so we decided to make our own application.
I've spent quite a long time trying to understand the packet format and have created a library, which targets .net core 2.2, that can be used to successfully communicate with this kit. In doing so, I discovered that the device seems to require a kind of "request to connect" command to be sent, via UDP. Straight afterwards, I am able to initiate a TCP connection on port 16000, although the first TCP attempt always results in a RST,ACK being returned - so a second attempt needs to be made.
What I've developed works absolutely fine on both Windows (x86) and Linux (Raspberry Pi/ARM) systems and I can send and receive data. However, when run on the Raspbian system, there seems to be problems when initiating the TCP connection. I could have sworn that we had it working absolutely fine on a previous build, but none of the previous commits seem to work - so it may well be a system/kernel update that has changed something.
The issue:
When initiating a TCP connection to this device, it will - straight away - reset the connection. It does this even with the manufacturer-supplied software, which itself then immediately re-attempts the connection again and it succeeds; so this kind of reset-once-then-it-works-the-second-time behaviour in itself isn't a "problem" that I have any control over.
What I am trying to understand is why a Windows system immediately re-attempts the connection through a retransmission...
..but the Linux system just gives up after one attempt (this is the end of the packet capture..)
To prove it is not an application-specific issue, I've tried using ncat/netcat on both the Windows system and the Raspbian system, as well as a Kali system on a separate laptop to prove it isn't an ARM/Raspberry issue. Since the UDP "request" hasn't been sent, the connection will never succeed anyway, but this simply demonstrates different behaviour between the OSes.
Linux versions look pretty much the same as above, whereby they send a single packet that gets reset - whereas the Windows attempt demonstrates the multiple retransmissions..
So, does anyone have any answer for this behaviour difference? I am guessing it isn't a .net core specific issue, but is there any way I can set socket options to attempt a retransmission? Or can it be set at the OS level with systemctl commands or something? I did try and see if there are any SocketOptionNames, in .net, that look like they'd control attempts/retries, as this answer had me wonder, but no luck so far.
If anyone has any suggestions as to how to better align this behaviour across platforms, or can explain the reason for this difference is at all, I would very much appreciate it!
Nice find! According to this, Windows´ TCP will retry a connection if it receives a RST/ACK from the remote host after sending a SYN:
... Upon receiving the ACK/RST client from the target host, the client determines that there is indeed no service listening there. In the Microsoft Winsock implementation of TCP, a pending connection will keep attempting to issue SYN packets until a maximum retry value is reached (set in the registry, this value defaults to 3 extra times)...
The value used to limit those retries is set in HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\TcpMaxConnectRetransmissions according to the same article. At least in Win10 Pro it doesn´t seem to be present by default.
Although this is a conveniece for Windows machines, an application still should determine its own criteria for handling a failed connect attempt IMO (i. e number of attempts, timeouts etc).
Anyhow, as I said, surprising fact! Living and learning I guess ...
Cristian.
I have a Raspberry pi with SIM900 GSM module. currently i am using ttyUSB0 as pppd but i also want to send AT commands (send/receive SMS) to SIM900 while pppd is active. I was created multiple virtual serial ports (like gsmtty1,gsmtty2 etc) but those are not working with screen/minicom.
While these virtual serial ports might work (assuming you are talking about the kernel's 07.10 multiplexing support), your first attempt should be to use the other serial device, e.g. /dev/ttyUSB1.
This is assuming the modem provides two serial endpoints, which it is not absolutely required to do, but virtual all modems that support USB does, so I would be very surprised if it really only had one.
Notice that the 07.10 multiplexing protocol requires explicit command and implementation support from the modem and is specified in a 3GPP specification which was created in the 90-ties to cater for the lack of multiplexing in the serial interfaces that were in use at that time (RS-232, IrDA, bluetooth).
But it required dedicated driver support on the operating side, and for windows there was no default drivers supplied so you had to install something additional (and I think the quality of those were not so great either) so 07.10 never got any serious momentum. Today USB's native multiple endpoint support have in many ways obsoleted the 07.10 protocol.
I am trying to connect a Temp and Humi probe Adafruit AM2315 and it seams that the only thing I need to do is to get i2c running on my Pi2. I can't seams to find the proper instructions or command line to get it config and running ? Can someone help ?
did you connect it directly to the RPi2 I2C pins, or did you use the 10KOhm resistors too..?
It seems it needs two rapid connections to wake up first, before starting to send commands, see here:
http://raspberrypihobbyist.blogspot.it/2015/02/using-am2315-temperaturehumidity-sensor.html
David
Im acquiring data from a sensor using RaspberryPi. Now the idea is to get the data streaming over an ethernet link to my Windows 7 laptop and do the monitoring and recording on the laptop. Can I get some advice on how to implement this in C/C++.
The idea is to get the signal from a sensor streamed to a Windows GUI.
You can push data from your raspberry PI to you Windows
You can have some sort of service on your Windows box and your raspberry PI can push information to your software running on your Windows.
or
you can pull data from your raspberry PI to you Windows
In this case, raspberry PI would be a passive provider and Windows would ask for data.
Hard to give you more information without more details but basically you decide who is going to the passive and active and program that way.
I personally would request data from the raspberry PI to Windows as I can have my service running and just update when I need instead of having my service running and suddenly have my data changing.
That said, it's hard to say without more details.
You need to tell what kind of programming language are you going to use.
According to your question, you need to dig into socket programming.
Recently,I linked my two Raspberry-Pi by writing a python script to establish a TCP connection between them.
and there is this protocol called "RTSP(Real Time Streaming Protocol)" to (as the name says) stream data in real-time.
(If you are to use python , there is this module called gst-python for streaming).
I think the above infos would give you where to start.