I am building an app but I wanted to test the device before start coding.
The device that I am using is veepeak BLE OBDII. I can connect to it using other popular apps with no issue e.g. CarScanner.
When using LightBlue app (BLE testing app), I can connect & see write and notify services/chars but when sending any AT command e.g. "ATZ \r" I always get "?" response.
Related
My project includes connecting multiple esp32 boards together in server client form, Server sends data to clients, clients receive data, get some input sensor data and send it back to server device. This is performed using ESPNOW(is there a better way to do this?). while performing this operation even thought the client send data only once to the server receives the same multiple times, then connection gets interrupted and then resets back.
The second part is the server device talking to the app using BLE and the app also sends data to server device. The BLE implementation works just fine, but when i combined the two codes(espNOW and BLE) and some other codes for Loadcells, the memory on esp32 was less, so i partitioned it to "Minimal SPIFFS" which gave me enough memory to upload the code, then when i try to connect to esp32 using an app ("FastBLE") it says connection failed.
This is the output on the Serial monitor when BLE connection was attempted was:
Guru Meditation error, Core register dump, Backtrace, then says rebooting.
I would love to know how to correct these two issues(espNOW and BLE)
I thought the problem was partitioning so i uploaded the individual codes with the same partition and it works but maybe together it gets messed up? i am not sure.
I am trying to set the memory location of my phone (Nokia 2730 Classic) but I am not able to set the storage location. I have also tried with the 7 port multi sim card hub and got same issue there as well. I am using the Ubuntu system and using Minicom and Screen command to connect serial port. When I tried to send SMS from the device using AT command it is working fine but the reading of SMS is not working due to storage location is not set.
While I am trying to execute command AT+CPMS I got below results.
AT+CPMS?
+CPMS: ,,,,,,,,
OK
AT+CPMS=?
+CPMS: (),(),()
OK
And when I try to set the location of storage using below commands then getting errors.
AT+CPMS="SM","SM","SM"
ERROR
AT+CPMS="ME","ME","ME"
ERROR
AT+CPMS="MT","MT","MT"
ERROR
AT+CPMS="SM","ME","MT"
ERROR
Please let me know if you have any solution.
Thanks
I learned that PUSH NOTIFICATION service is like a persistent TCP connection.
But I don't know how maintain the connection even if the phone terminate the app.
In mobile application, if the subscription is destroyed, how we publish and deliver the message?
Should I use GCM, APNS or SMS? And wait until client subscribe the topic?
That's correct, you have to be connected with the broker (mosquitto broker in this case) to receive the push notification (you also must be subscribed to topic).
In Android I'm using paho client libray, a Service for keep connection in background, and BroadcastReceiver to start service at reboot.
For iOS you can find swift and Objetive-C MQTT-client librarys (I'm using CocoaMQTT) but you can't keep connection in background indefinitely. You have to use APNS.
I'm writing Windows Phone 8.1 application and I want to receive the push notifications from the SinglaR server. It is working, but only when the application is on the foreground.
How can I receive the notification when the application is in the background or shut down?
Does PushNotificationTrigger catches the notification from the SignalR? Or does the PushNotificationTrigger work only with WNS?
Thank you
SignalR offers realtime connection and data exchange while the application is active and connected. Once application goes to background it is effectively closed and all active connections are closed.
If you want to send push notifications, that is something OS offers and is not something you do via your own framework. If you want to receive notifications while the application is closed, you need to use the standard push functionality built into the platform. And which is completely separated from SignalR.
You can still use your website to send push notifications though.
I'm using a gsm modem itengo 3800. I'm currently doing a project that interface with a website to send/receive bulk sms, schedule sms and etc.
The problem is, i don't really know which should it be coded in. Should it be coded as a asp.net web application? or should it coded as a windows programs that interface with the web application for send/receiving sms?
Also receiving/sending multiple sms is important, so i requires queue or anything for buffer? Would be glad if sample programme is provided.
Because sending messages via gsm modem can be slow, what I'd do is have the ASP.NET app post the messages to a message queue, then have a windows service read the queue and send the messages. This allows the website to avoid any degradation issues when sending out lots of messages.
Here is a decent article that discusses using MSMQ: http://www.15seconds.com/issue/031202.htm
The ASP.NET app would:
MessageQueue queue = new MessageQueue(QUEUE_PATH);
Message msg = new Message("5555551212|message");
queue.Send(msg);
And the service would listen:
MessageQueue queue = new MessageQueue(QUEUE_PATH);
Message msg = queue.Receive();