I bought Beagle Bone Black.
I conneted Serial cable (CP2102) to beagle bone.
I am able to get log massages over minicom(console).
But I am Not able to send data (login and Password ) to Beagle Bone Black.
I get Solution Myself.
I changed minicom setting. Hardware flow control was enabled.
Solution : I disabled Hardware flow control in minicom setting.
If hardware flow control enabled. Then minicom will not able to send data to beaglebone black via serial cable. Minicom will take log maggages from beaglebone.
Related
I can't for the life of me figure out why my ESP8266s create WiFi access points.
I plug it in and send an empty sketch, and it creates an AP called "ESP_28F2F8" and here the ESP is at 192.168.4.1.
I do not want it to create a WiFi network. I just want it to connect to one.
Has anyone else run into this issue? Is this perhaps some weird OS?
That's normal operation of the underlying Espressif's SDK. It remembers some of the settings in flash, like the last created AP and last WiFi network connected.
You need to run
WiFi.softAPdisconnect(true);
so the ESP disconnects all clients currently connected to it, disables AP and remembers it to flash.
If you might also need to disable automatic connection to the last WiFi network, you need to call:
WiFi.setAutoConnect(false);
I want to understand how the AP provisioning works on a headless device, specifically for IoT applications (I'm developing on a Texas Instruments CC3200). It seems that the universally accepted method of provisioning an IoT device is for the device to act as an AP then the user connects to it in order to send the Wifi AP credentials via smartphone. I'm assuming this could be done via UDP or TCP.
Most of these IoT modules can act as an Access Point OR a Station but not both at the same time. So how does the device know that the Wifi credentials are correct? It must have to shut down the AP that it creates to try and connect to the user's Wifi, right? If the credentials are NOT correct, how does it let the user know on the smartphone side? At this point, the device's AP doesn't exists and the user would have to jump back on it again. What's really happening there?
So how does the device know that the Wifi credentials are correct ?
It have to try if using those credentials AP association is possible. For successful connection SSID, passphrase, encryption type have to be provided. All or some of those information can be already in device memory ie. application can connect only to known SSID.
It must have to shut down the AP that it creates to try and connect to the user's Wifi, right?
Yes. In case of TI CC3200 you can switch mode while application is running.
If the credentials are NOT correct, how does it let the user know on the smartphone side?
It is highly implementation depending. For example, if your IoT device cannot obtain outside world it can switch back to AP mode, what can be detected on the smartphone side. Other solution is that you can send and receive data while in AP mode so it is possible to write server application that will inform smartphone application about the connection state.
At this point, the device's AP doesn't exists and the user would have to jump back on it again. What's really happening there?
Not sure if understand this question. As I mentioned above IoT device knows the state of AP association (TI CC3200 SDK return known values for wide range of errors), if IoT device cannot connected as station using provided credentials it should rollback to AP mode.
I don't know if this is possible.
I bought a remote controlled car and now I want to send signals from my computer, rather than the remote control.
I'd like to send the signals with my wireless card (RC and WLAN Card are both 2.4 gHz). So the card needs to give me all traffic in the air. Not only WLAN signals.
Are there any wireless cards that can do that?
It doesn't matter if this is only possible on one OS.
First make sure that your remote controlled car supports WLAN interface because most of the remote controlled devices are working on either Infrared interface or Bluetooth.
If your remote controlled car supports WLAN interface then only you can send WLAN signal to your car using wireless card (RC and WLAN Card are both 2.4 gHz).
I will suggest you to check these thing first :)
BACKGROUND
We're trying to use an iOS app running on iPhone/iPad to give WiFi credentials to an embedded device (using an ARM SoC running Linux). The embedded device starts an AP (access point), we instruct the user to connect to this AP and then the user submits their WiFi credentials. After WiFi credentials are received the device drops the AP and connects to the WiFi the user gave credentials for.
Initially, we try to hit a PHP page to get the list of WiFi networks the embedded device can see.
ISSUE
We instruct the user to join XYZ network (in iOS they must background the app, go into settings and switch to our WiFi network). We listen for an app resumed from background notification, check the devices current ESSID (ensure its our AP ESSID) and try to hit a PHP page to receive the list of WiFi networks. Often, this connection fails reports "The internet connection appears to be offline" (or something of that nature).
We currently have a stop gap when this happens telling the user to toggle their WiFi off and then back on (in settings). The device will reconnect to our AP as it's the most recently connected network. This ALWAYS fixes the issue, we've never had to toggle the WiFi twice in order to reach the PHP page on the device. Please tell me any possible way we can avoid having to instruct the user to toggle WiFi and still access PHP pages on the embedded device.
Note: when we're connected to the AP (whether this bug is active or fixed) the device DOES NOT show the WiFi icon in the status bar. We assume this is because the AP doesn't have a viable connection to the internet (can only access pages served by the embedded device). We've been testing on a device that has LTE cellular access, but the error still says "Internet connection appears to be offline".
Obviously we have a DHCP server running on the embedded device.
It's looking like this was caused by an omission in our dhcpd.conf file.
This omission was causing iOS to believe the connection was unviable.
We added the following line and are getting much better results:
option domain-name-servers 10.10.10.1;
I want to sniff wifi packets with wireshark but monitor mode seems to fail. I'm using backtrack 5 and an alpha AWUS036H wifi usb card, i try to sniff my own box without encryption.
Here is what i'm doing to activate monitor mode :
root#root:~# airmon-ng start wlan0
wich seems to be working :
root#root:~# iwconfig mon0
mon0 IEEE 802.11bg Mode:Monitor Tx-Power=20 dBm
Retry long limit:7 RTS thr:off Fragment thr:off
Power Management:on
However when i start capturing on mon0 in wireshark i'm only getting broadcast packets.
In capture options the "capture packets in monitor mode" option is grayed out.
I do not understand what's going on. Any Ideas ?
What channel number is your mon0 interface set to?