I have a client that would like a small PIC board that plugs into a PC's USB as a dongle in HID mode. It would basically just transfer small amounts of data over RF to another device across the room.
They would like the data to come from the web. ie. user clicks a link in their browser which wakes up the PIC board and begins a download to the PIC device without the need for another application to visibly popup in front of the user.
I would think this can't be done without the setting up the browser preferences and assigning a custom application to recognize the data file. The security issues with a link initiating this kind of flow of events must be too great unless I'm missing something.
Has anyone done something like what I described above?
You could write a small piece of software that runs in the background on the PC (e.g. a Windows service), and:
Interfaces to the PIC device via USB
Provides a web interface on port 80 or probably some other port, which the browser can then connect to.
If the PIC device is network connected (e.g. has an Ethernet connection, and its own IP address on the network) then the PIC device could provide a web interface to control it. I don't know how feasible it is to fit a small web server onto a PIC though--that would be a tight fit.
Yeah that sequence of events doesn't seem too kosher. Perhaps a browser plugin or a program running on the PC that handles communication between the PIC and web would be better?
Related
we are doing a project on image processing using a camera,raspberry pi3 and a gsm module. Above mentioned things are with a flying drone. I can send a notification message to a mobile using gsm module if required object detected on the cam. But we store that image to view on a webpage or through a mobile app easily. while it's flying it can't connect to the internet. So can you suggest a solution to get those images when it is inside our home wifi range.(any how we can get the images from sd card but i need to get those as soon as possible it detected the wifi) . Thanks in advance
You could consider using "tethering", a.k.a. "Personal Hotspot" in Apple parlance, on your mobile phone.
Basically, you would enable the Personal Hotspot on your iPhone and allow your RPi to connect to it via Wifi. You would have to check your setup, but my iPhone takes IP address 172.20.10.1 for itself and dishes out IP addresses to clients which are the same but with the 1 replaced by a small number under 13.
You can see from here how to setup your RPi to automagically connect to your Hotspot whenever in range. You could also consider fixing a static IP address when on that network, so you know where the RPi will show up for sure.
You would then ensure that Apache, or maybe lighttpd which is lighter weight, is running on your RPi.
Then, your app on the RPi would store its image as image.jpg in Apache's DOCUMENT_ROOT directory, probably /var/www/html/image.jpg but check.
Now, on the iPhone, start Safari and browse to:
http://172.20.10.N/image.jpg
where N is a small number. You should see your image and be able to save it to DropBox or Photos or iCloud Drive for others to see.
Of course, once your RPi is connected to your iPhone's hotspot, it can FTP or ssh copy the image to any website or other server on the Internet it has access to itself.
I have understood your question also I have cheapest solution to build your project. you will be needing 3 modules
ESP8266 (Wifi module)
SD card logger
Camera module(go with your choice, try ESP8266(But I have not tried it))
Combining all these can get your work done. But most instructing part is When connected with wifi it should transmit video to webpage or app and when not connected should log video to SD card
Below is my try to solve your problem, if you have any doubts feel free to ask your question.
ESP8266 is an WiFi module, you can connect it with an hot-spot or an router, similar to any WiFi device's on successful connection it throws 200,OK failing will throw 404 or so. Technically just like any TCP devices it will work. You can connect, disconnect, send and receive data continuously using software(using code you write).
0-code for camera unit starts
1-try connecting WiFi && start the camera and start logging into SD card //InCase if WiFi module takes longer time than usual to connect, this will prevent data from losing
2-if connection failed - continue writing to SD card
3-else(connection made) - start streaming the data && stop the SD card logging and save the file and create a new empty file so that we can save on next connection out without wasting data.
4-check for connection status in regular interval (goto step2).
5-on any external inputs(like click an image)
most important thing: code for your camera interface should work independent from the flight controller code.
-NandhaFrost
I bought one of these:
https://www.aliexpress.com/item/Smart-finder-Key-finder-Wireless-Bluetooth-Tracker-Anti-lost-alarm-Smart-Tag-Child-Bag-Pet-GPS/32806261079.html
As far as I can tell it is a BLE (Bluetooth Low Energy) location tag.
I downloaded the app for it onto my iphone, and the app instantly recognised it and connected to it. The iPhone app seems to know how far away the tag is - it has a little map of the local area and says how many feet away. I was able to set the device name via the app, but I'm not sure if that set it locally or on the tag itself. The iPhone app also has a "find" button - when you press it, the tag beeps.
So I want to know how I can program this thing myself. I want to be able to identify it when it is nearby, connect to it and make it beep. I've searched for quite a while but not come up with much.
I'm assuming (wrongly/rightly?) that there is some general standard or approach for talking to these BLE location devices and carrying out the basic functions with them - but what is that standard - where is the documentation?
Does anyone have any idea how to program these BLE location tag devices?
BLE devices typically communicate using GATT, either using standard GATT services, or custom ones. The command to make it beep is probably implemented using a custom GATT service.
For finding out the distance to the beacon, typically the RSSI is used. This is a measure of the received power. It needs to be compared to the output power at the emitter. Usually beacons will put their output power in advertisement data, so it can be used without connecting to them. Here since the app is also able to send commands to the beacon, chances are it keeps a connection to it and has a custom GATT protocol to retrieve the output power.
Here is what I would suggest:
Read up on BLE, especially advertising and GATT. For instance read this for advertising and this for GATT. The full BLE spec is available here but should be used for reference and not introduction
Sniff the communication between your device and your phone. You can see this other answer of mine to get started
Replicate the communication protocol in you own app. For that you'll need to use your target platform's BLE libraries. For instance for iOS it is CoreBluetooth
First of all, I won't go into details, cause there are a lot of them, and I dont want to write (a too long) essay. There is TL;DR section at the end, because I have a specific question, but maybe some additional info can help.
I have a device that is made of a GRU (glass room unit) and espressif (esp8266).
GRU and esp8266 communicate via serial, with GRU as master. GRU is programmed with an internal tool, and I can monitor everything on it, including the info it gets from esp8266.
There is a test/development device, that has espressif on top of the GRU, so I can easily take it off, reprogram/reconfigure it, and put it on.
Espressif is inside of a GRU, and downloading stuff to flash is a real pain. There is whole process including a OS switch (from Win7 to Linux and back). Console output on espressif cannot be done, or at least not in the time frame I have.
For esp8266 I use non-os SDK V2.0.0_16_08_10.
Espressif can be configured with downloading a configuration to flash, or via UDP (over a network if connected, over its AP if its not connected).
Algorithm for Wifi:
1. Try to connect to a network from configuration
2. If it succeeds, raise a flag for that
3. If it fails, enter dual (STATION+AP) mode and raise a flag for that
The reason espressif is not always in dual mode is that it affects multi-cast operations.
Configuration over network is done by a Java aplication I wrote.
Scenario 1
I've configured a wifi router, configured all (x19) of the devices (espressif in devices that is) to connect to its network. When I turned them on, they would connect one by one. The ones that didn't entered dual mode and could be configured via the app.
All well.
Scenario 2
I've wanted to test the system in real world, so I reconfigured them to connect to the our firms network. Additionally when I was already going thru the whole process I've downloaded latest firmare to flash.
I expected that they would connect or enter dual mode and create their own APs. But they did not.
I tested then the code and configuration on espressif whose console output I could monitor, and everything worked.
I tested then the code and configuration on the test device, and it worked again.
I've then redownloaded the code and configuration to one device, and it didn't work.
TL;DR
I have two devices, espressif on a GRU and espressif inside of a GRU. Both connected to one network. Esp on a GRU work for another, Esp inside of a GRU doesn't work for that other network.
They have identical code and configuration, so it shouldn't be a software issue.
Does having espressif inside of a device jams its signal enough that it can't go trough? Device is not big (5x5x2cm).
UPDATE 1:
While I was writing, the espressif inside of a GRU managed to connect to network. I then restarted it so I can check that it can do it again, and it can't connect again.
It took me about 10 minutes to write the whole question.
There are two things that seem to have caused the problem.
When I removed gpio_init(), network stuff became faster, much much faster. Everything on it, connecting to AP, creating AP etc...
I've changed my config and wifi code, so that it now stores the ap and station config to flash via API.
I only check if its internal config is the same as mine from flash. If it isn't, it saves it. Now, I only control the current opmode.
Im writing application that communicate (via serial port) with electronic device which i designed myself.
When my PC application starts - it opens available COM ports one by one and it sends some string ("What are you?" for example).
My device is programmed, to reply to that "magic question" with own ID (for example: "I am evil device for supervising employees").
When my PC software receive that "magic reply" it starts working normally and its not searching other ports anymore.
Of course im not using stupid questions in data transmission, its just example.
Question is - can i send strings like on all (not busy) ports, to discover my device?
If I can - how that "question" string should look? Are there any normalized standards?
This is not first project like this on my desk, but now im developing solution for little industry and i need to pay more attention what my application is doing, because there may be other devices connected to COM ports and I do not know how they can react.
Im sorry, if i made some language mistakes, english is my third language.
Thanks in advance for replies.
After Alvin Wong confirmed my concerns I thought about it again and redesigned my device discovery functionality, because I don't want to abandon that idea.
I will send unique-complicated-ID every 1-5 seconds from device.
When my PC starts - it will try to open sequentially all available ports and will listen for that ID for few seconds.
If application receive that ID - it will be confirmation, that port number/name is correct and I my connection is established.
No, you wouldn't want to do that.
When you are using COM serial port, you have no idea what is plugged into the port. It could be nothing, your device, a modem, a mouse (though I believe nobody uses this anymore...) or whatever you can't even imagine.
Imagine if it is connected to another computer (probably a Linux/router), sending things may lead to execution of "that command", thus creating unexpected effects (though your program may not notice). Or if it is some badly-programmed device, it may trigger a bug in the firmware, thus failing the device and making it malfunction.
In short, in the worst case, you can cause a catastrophic event.
Serial (RS232 or UART I assume) communications don't have a designated transfer protocol (in contrast to USB which has one) to identify a device, so it isn't fail-safe. The user must make sure he selected the correct port. This is probably one of the reasons why hardware manufacturers choose USB, and one of the reasons why USB is so popular, even to computer idiots.
we want to route the call to ip network instead of GSM network. for that purpose first we are connecting our mobile phone to a PC through bluetooth. So we want to transfer the real time audio data to that PC over bluetooth. Could you please help..
If you can trick the mobile phone to function as a bluetooth headeset [profile] -- which I doubt any phones would support because phones are, well, the consumers of such headset devices -- then you could use it like any other "headset" device. (It would be much more feasible to just purchase a headset or plug in a microphone.)
As far as "where the real time audio data is stored?" -- well, that just won't go anywhere. The "data" (perhaps already in an encoded/delta form) is briefly (like milliseconds!) "stored" in a few small buffers / integrated circuits in the radio circuitry. This circuity will vary based upon phone/radio module used and is not accessible from a PC.
Happy doing productive things.