Is it possible to connect 8 realsense in one PC without interference?
Anything need for it??
I want to use them with sdk for unity project(win10).
If it is possible, please notice the product and sdk.
thank you!!
Check:
Multi-camera synchronization, IR interference, and USB bandwidth questions
Are multiple cameras supported yet?
Both give as a starting point to use the R200 camera's and librealsense. In order to have a good USB3.0 throughput and minimum frame loss, you would need a very good USB3.0 controller card. This card should be a good starting point. Startech PEXUSB3S4V, buy two of them and insert them in a PCIe 2.0 slot in your pc.
Then it's probably needed/wise to program 8 separate threads, so each Realsense gets it's own thread. So for processing power you would like to have something like a 6 core processor, able to handle up to 12 threads.
Keep in mind I haven't tested this. But if you want to build such a system, I would start in this way.
Related
I am new to ESP8266 and started just building basic devices using it. However I am using USB 5V wall adapter as nodeMCU has USB UART converter to 3.3V.
If I want to make it battery powered what is simple , small ( in volume so that it can fit along with nodemcu and sensors in a small case) and economical approach that keeps my nodemcu still safe?
-One option I can think of is to connect a Li-ion battery of 3.7V to VIN.
-Another one is to use bigger voltage and use a converter to convert it down to around 5V and then use that to connect to VIN.
Please let me know if this works ? else if there is any better option please do suggest. Also if you are referring to any items/products please help give the exact model numbers so that I can search on internet to consider buying them.
Lastly I am not much aware of electric circuits & terminology yet ( learning them), so please help explain me in basic terms possible.
Ps: this question was seen on stackoverflow some times but I couldnt find one single consolidated answer and am confused by it. Appreciate your understanding.
Thanks,
Sridhar.
This really would be better suited for the electronics sister site or a esp8266.com forum but for what it's wort here's my input.
IMHO the most convenient option you have is to buy a devkit with a LiPo connector. I recommend a WeMOS D1 mini plus a fitting battery shield. An alternative is the Adafruit Feather HUZZAH.
It can sometimes be a bit of a challenge to find the right connectors for those boards. Gotcha! different revisions of those boards might use different connectors. Currently the WeMOS battery shield uses a 2 pin JST PH 2.0mm.
No, you cannot power a NodeMCU using a 3.7v li-ion battery directly. A fully charged Li-ion battery outputs a voltage of 4.2v. The NodeMCU board has a (5v and above) vin slot along with two 3.6v slots. If you directly connect the battery to the 3.6v, it may fry the NodeMCU board. So typically, there are 3 ways you can connect the battery without frying your board in this scenario:
You can use a boost converter to convert the 4.2v output to 5v. Then connect it to vin. This will draw more current and battery discharges quickly (eg: MT3608 step up boost converter).
You can use a buck converter to convert the 4.2v to a steady 3.6v (eg: LM2596 step down converter).
Finally, the most efficient way is to connect a 3.3v LDO in middle. The difference between using a buck and LDO is, buck provides a constant and steady 3.6v output, where as LDO's output depends on the input voltage from battery (eg: S111733PI).
I live in a building where the laundry machine is a bit far away from my suite. There is only one machine there so only one person can use it at a time. Quite often I take my laundry there just to realize that the machine is in use so I have to go back defeated and try again later. I want to build a doodad that can detect when the machine is in use and broadcast that information throughout the building so that I know that the machine will be available before I go there.
This question is not about how to build the detector. I am planning on using a raspberry pi somehow. This question is about what do I do when I detect that the machine is in use. How do I broadcast that information mainly to myself or potentially to anyone in the building?
I need a cheap solution (< $100). It has to be wireless. The signal has to travel approximately 30 meters in one direction. The broadcast should be readable on any laptop or cell phone (not a requirement but nice to have).
I was considering making an android app using WiFi direct. I'm sure others in the building would be interested in this app and I can use them as peers to extend the range of the broadcast. But I don't like this solution because I know that wifi direct doesn't work with iOS devices. Also this solution will require others to side-load an apk which they might not know how to do.
Please let me know if you can come up with something a bit less reliant on p2p and more platform independent.
I'd like to have an iPhone and an Arduino-based device talk to each other. Here are the requirements:
I want to fully rely on iPhone's built-in components without any peripherals (for example, HiJack).
The less configuration before the two can communicate, the better. This means a WiFi-based is not desirable, because we'll need to set up Wi-Fi credentials for the Arduino beforehand.
Bitrate is not important. Only a few bytes are exchanged.
As cheap as possible.
I see that Bluetooth 4.0 LE (for example, Stack Overflow question iPhone - Any examples of communicating with an Arduino board using Bluetooth?) meets my requirements, but are there any cheaper solutions?
One thing that came into my mind is sound - the way Chirp used to share data between two iOS devices, but I don't know if is feasible on Arduino and, if it is, how much it would be. Any other solutions?
I can think of a few options:
Bluetooth, you can get a cheap one from eBay for about $10
Wi-Fi using Electric Imp (cost around $30), which is very easy to setup using the brilliant BlinkUp technique. See the project ElectricImp, control central heating via iPhone for an example.
Chirp is a brilliant idea as well. From a hardware prospective I see it is feasible to do in Arduino; you just need a MIC circuit ($8) and speaker.
However, the real challenge is the software side, i.e., the algorithm that you will use to encode data as sound and vice versa. If such algorithm requires intensive calculation, you might not be able to do it in Arduino, and you can consider using an ARM-based microcontroller.
I want to port a good OpenCV code on an embedded platform. Earlier such stuffs were very difficult to perform but now TI has come up with nice embedded platforms which are comparatively hassle free as they say.
I want to know following things:
Given that :
The OpenCV code is already running on PC smoothly. (obviously)
Need to determine these before purchasing the device.
Can't put the code here in stackoverflow. :P
To chose from Texas Instruments: C6000.
Questions:
How to make it sure that the porting will be done?
What steps to be taken to make it sure that after porting the code, will run (at least).
to determine whether the code might require some changes to make its run smooth.
The point 3 above is optional.
I need info which will at least give me some start up in this regard.
What I thought I should do?
I am to list the inbuilt functions down.
Then to find available online bench marking for those functions for the particular device like as shown towards the end of this doc.
...
Need to know how to proceed further?
However C6-Integra™ DSP+ARM Processor seems the best.
The best you can do is to try a device simulator (if it is available), but what you'll see there is far from perfect.
Actually, nothing can tell you how fast and how well the app will run on the embedded device before running you specific app on that specific device.
So:
Step 1 Buy it
Step 2 Try it
Things to consider:
embedded CPU architecture: Your app needs a big cache? how big is the embedded cache?
algorithm: do you use a lot of floating point operations? how good is the device at floating point ops?
do you have memory transfers? data bus on a PC is waaay faster than on embedded
hardware support: do you use a lot of double-precision calculations? they are emulated on ARMs. They are gonna kill your app (from millisecons on a PC it can go to seconds on a ARM)
Acceleration. Do your functions use SSE? (many OpenCV funcs are SSEd, even if you don't know). Do you have the NEON counterpart? (OpenCV does not have much support for that). The difference can be orders of magnitude from x86 SSE to embedded without NEON.
and many, many others.
So, again: no one can tell you how it will work. Just the combination between the specific app and the real device tells the truth.
even a run on a similar device is not relevant. It can run smoothly on a given processor, and with another, with similar freq or listed memory, it will slow down too much
This is an interesting question but run is a very generic word in this context, therefore I feel the need to break it down to other 2 questions:
Will it compile in an embedded device?
Will it run as fast/smooth as in a PC?
I've used OpenCV in a lot of different devices, including ARM, SH4, MIPS and I found out that sometimes the manufacturer of the device itself provides a compiled version of OpenCV (for my surprise), which is great. That's something you can look into, maybe the manufacturer of your device provide OpenCV binaries.
There's no way to know for sure how smooth your OpenCV application will be on the target device unless you are able to find some benchmark of OpenCV running in there. PCs have far better processing power than embedded devices, so you can expect less performance from the target device.
There are 3rd party applications like opencv-performance, that you can use to test/benchmark the environment once you get your hands on it. And if performance is such a big deal in this project, you might also be interested in this nice article which explain some timing tests done on couple of OpenCV features comparing implementations using the C and C++ interfaces of OpenCV.
My and my fellow students are deciding on a choosing a simple microcontroller to do very basic image processing. We are basically trying to implement template matching to find a set of objects in specific portions of the image. We'd like to use a connect a webcam to the microcontroller to do the job take the pictures and look for the objects. We also require basic wireless communication (e.g. bluetooth or wifi).
I don't think we will have the luxury of using state-of-the-art microcontroller, but something thats been around for a while (due to budget and stuff). Could anyone please advise on which specs of the microcontrolelr would be the most relevant for the above task (e.g. CPU, MIPS, etc).
Thanks a lot!
For this kind of a task, I would say the amount of RAM is the most relevant spec.
A microcontroller with an external memory interface allows you to extend the data space with additional SRAM to hold your image data.
Also note, that memory is needed for any protocol stacks you need to implement (Bluetooth, TCP/IP even more so).
You probably want to have total RAM in tens of kilobytes, preferably 100+ kB.
It is also nice to have plenty of program memory available when learning and experimenting. Later on you can try to optimize and squeeze your code into a more confined device.
As for the architecture, choose something you can easily find development tools and examples for.ARM, AVR and PIC are all good candidates among others.
Also find out what interfaces you need to use to
control the camera (e.g. I2C or SPI)
read pixel data (e.g. parallel or analog)
Connecting directly to a webcam's USB interface would not be a straightforward task, as the microcontroller would need to act as a USB host.
Good luck with your project!
You may need a microcontroller with following features:
USB 2.0 Host controller
1.2MB of memory for buffer 640*480*2(bytes per pixel)*2(double buffer)
(you may use lower resolution if there are not enough memory)
Wifi controller
CPU power strong enough for your task
Ready open source code
It seems that broadcom controllers may be useful here.
Also, you can by off-the-shell Wifi router with usb port and use it for your project
(i.e. Linksys E3000 )