Need to receive CAN Signals on AOSP emulator which are created virtually.
Not found any way to send or rercive CAN Signals virtually
You will need to create an abstraction that allows you to "inject" virtual CAN signals into your event processing queue.
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I'm researching and trying to building a RC car that can be controlled by the internet. I've started looking into how communication over the web works, but I seem to be going nowhere. My goal for the project is straight forward:
The RC car has an on-board camera and 4g wifi router that enables communication (driving commands, video streaming) over the internet. A Raspberry Pi will serve as the on-board computer.
I will be able to control the car with my PC even across the globe, as long as I'm connected.
I want to preferably do as much by myself as possible without relying too much on other people's code.
So here are my questions:
How does an application communicate over the internet? What is the interface between the application's logic (e.g pressing "w" to go forward), and transmitting/receiving that command over the internet?
How is video data stream handled?
I've looked into WebRTC and WebSockets for communication, but they are aimed at providing real time communication to web browsers and mobile, not something like a raspberry pi, and I'm still in the blind as for exactly what technology should I use, and in general the overview and architecture of real time communication.
All I've achieved so far was an app that sends text messages between devices through a server on my network, with very primitive reading/writing using java Socket.
In short, what does messenger/skype/zoom do in the background when you send a message or video call?
Any guidance would be greatly appreciated.
First things first. You cannot do real-time control over Internet, period. There is absolutely no way to guarantee the delivery latency. Your control commands can arrive with a delay from milliseconds to seconds, or never. No way around it.
Now, you can still do a number of reasonable steps to absorb that unpredictable latency as much as possible and safe-guard your remote robot from the consequences of the unreliable communication.
For example, instead of sending the drive commands directly - as in, acceleration, deceleration, turn angle, etc., you can send a projected trajectory that is calculated from your drive commands locally on a model. Your RC car must be sufficiently smart to do some form of localisation - at the very least, wheel odometry, and with a good enough time sync between the sender and the RC car you'll be able to control the behaviour remotely without nasty consequences of drive commands executed at an unpredictable delay.
You can add a heart-beat to your protocol, to monitor the quality of the communication line, and if hear-beat is delayed or missing, initiate emergency stop.
Also, don't bother with TCP, use UDP only and maintain your own sequence counter to monitor missing packets. Same applies to the telemetry stream, not just command channel.
I want to read the CAN bus and get the data from a specific device on the CAN bus. I have implemented this previously using the Socket communication api that is available in the user space (sys/socket).
I now have a similar requirement but this time working on device drivers which work in the kernel space. The same socket communication is i suppose not available in the kernel space which is why i guess i am not able to compile the kernel module with #include .
An approach i have come up to is to create a device driver for device creation and a supporting user-space program to interact it and provide CAN data by using socket communication. If there is any better approach please suggest me.
Can a device connected to main processor can initiate a i2c communication.
For example, FAN connected using i2c bus, is it possible for a FAN to send a feedback to main processor.
Common solution to a problem like this is to have a separate interrupt line.
I3C supports in-band interrupts, if you're not set on I2C yet.
I've got a guitar amp with a midi interface. I'm planning to see what's possible with the device that hasn't been built-in by the manufacturer. Since I have no experience with MIDI I'd like to know if it's possible to ruin a MIDI device by sending wrong data.
I'm not sure what data I'd like to send, and the device is basically a black box without documentation, so I can't give much more details. But one thing I'd like to attempt is overwriting the built-in effects.
MIDI commands are parsed and executed by the device's firmware.
Whatever effect(s) a command has is determined by what the firmware is programmed to do when it receives that command.
Typically, unknown commands are ignored, so it should not be possible to ruin a device by sending random data.
Most devices do no have any permanent state.
However, some devices allow upgrading their firmware through MIDI, so if you use the correct SysEx command, and manage to get any checksums correct, it would be possible to replace the original firmware with your own code (or some non-code that prevents it from working).
I have an external device that we manufacture that basically monitors 4 voltages, converts them to a 16 bit digital number then streams this info back to a PC every 100mS or so, using a serial over USB style chip. Basically a data logging system.
We would now like to collect this information on an iPhone and I am wondering what is the best way to get the data into the iPhone?
I am assuming there is no way we can physically connect directly to the iPhone dock connector as the protocol to do this is not available to iOS developers?
Obviously we could do it over a WiFi network but there will not always be one and we want to keep the external hardware fairly simple, i.e. no need for a computer or Wireless router etc.
If we add Bluetooth connectivity to our hardware would this work? I read that only 'Made for iPod' type Bluetooth devices will connect, in which case how can we achieve 'made for iPod' status? It would be relatively easy to add the necessary Bluetooth chips to get the system up and running.
In an ideal world we would like to do this without having to use a 3rd party interface.
I have been thinking about trying to digitise data as an audio signal – like a modem, and send it into the line input jack, but I don’t think it will be fast enough – this would be new territory for me.
Anyway all suggestions gratefully received!
Thanks!