I'm a developer for different mobile and backend systems and pretty new to network and hardware stuff. I want to build a system/network with 6 cameras placed 100m away in the field, which I want to control with a web interface. I know how to build such interfaces, but I have no clue how to connect the hardware. I thought about the following:
I need 6 cameras(*infos added below) standing side by side with ca. 1.5m space between. These should be connected to a switch, so a 100m wire (USB or LAN, I prefer LAN) goes to a RPI which can setup the web interface controlling the cameras like ".../whatever/camera-slot-ip-or-number".
As I said in the introduction, I have no clue how to start, because actually webcams using USB as a std, but does they provide wake on LAN features? Or is it better to do it with 6 USB-cams and several RPIs?
I hope someone with a better hardware understanding can help me.
Thanks a lot
Specification for the cameras:
HD is not needed, but it should recognize a 0,5cm round hole in a 50x50cm area properly. The distance between camera and object is 7-10m A color image should transmitted, but there only 2 main-colors.
EDIT:
draft 2.0:
Piping USB through a 100m cable is not easily going to work.
Some models of USB cameras can be used with the Raspberry pi, but the performance (speed of taking a picture, and image quality too) are better with the 'native' raspberry pi camera.
The Pi also has a built-in H.264 video encoder, so you can stream live video with relative ease if you want to. A quick and brute way of doing that is to pipe the output from the built-in raspivid application to your own application that then handles flow control and pipes the data further to a socket.
If wifi does nto work for you, then you could pick some other raspberry pi model with an ethernet interface and go that way.
Also, the cost of additional Raspberry Pis (especially the zero w) is so low that the easiest and most cost efficient thing might just be to one raspberry pi camera on 6 raspberry pi's. If connecting them with Wifi works in your application, you can use the Zero W model and then you just need to feed power to them via cable.
Thank you for the updated information. I am pretty much in agreement, I think, with Sami's answer but wanted to add a few more details that are a bit big and unwieldy for a comment.
If you look across the top of your diagram, you have 6 stations at 1.5m intervals, so the width of your diagram is 7.5m. That is easily within wifi range so I am thinking a wifi access point on any of the 6 stations and a 100m Cat 6 Ethernet cable down the length of your diagram to the front-end.
As your processing doesn't sound too involved, you can likely get away with just a Raspberry Pi Zero W and a v2 camera at each station and save a fair bit of money vis-à-vis Raspberry Pi 3B+.
One thing that does concern me is looking for 0.5cm from 7-10m. The lens on the Raspberry Pi camera is pretty wide angle and a 0.5cm hole is going to be awfully small at 10m in a wide angle shot unless at very high resolution. I haven't done the maths, but I think you will be looking for a telephoto lens if such a thing exists... the maths now follows.
The horizontal field of view (FOV) of v2 camera is 62 degrees, so half that is 31 degrees and the camera is 1000cm away. So:
tan(31 degrees) = half the FOV width / 1000
So, at 10m you will get 1200cm of stuff across your image and that will be imaged by 3,280 pixels on the sensor if you shoot at the very highest resolution. So, each pixel in your image will correspond to an area 0.3cm wide whereas you are looking for holes 0.5cm wide - so it will be pretty marginal as to whether you can make it out... maths is subject to revision after a glass of wine later.
Related
I'm working at the mine on the drill machines. I've been given a project to find a communication system that can interface magnetic pickup sensor (MSP6744) with a redlion conveter (IFMA0035). It has to be a wireless transmitter and receiver. We are measuring speed of the rotating rod (rpm) on the gear teeth of the powerhead or gearbox by magnetic pick up. The sensor produce small voltage and max frequency of 1850Hz. This will be converted to 0-5volts then is send to control system.
I've been searching on google and contacting many companies but no luck.
I did my research and found one of the possible solution is to design it using ESP32 but i need lot of guidelines on this one.
Magnetic Pickup Description: A magnetic pickup is installed over a gear and as the gear turns the pickup will create an electric pulse for each tooth on the gear. These pulses are then read by the instrument which interprets it to indicate the correct RPMs or speed.The signal from the magnetic speed Sensor, teeth per second(HZ), is directly proportional to rotation speed.
First I want to point out that I'm very new to Raspberry Pis. I have bought a Raspberry Pi Zero for my project, because Arduino did not have enough horsepower.
My Project involves an I2C sensor and audio output (I2S). The audio is generated on the Raspberry and that is why I need the computational power.
Now I'd like to know what would be a good choice for the operating system. I don't really need anything else but the I2C and I2S and some math to generate the sound. The project is going to have the Raspberry embedded in the system and is battery powered, so it should be able to survive sudden power loss.
I found something relating to Real Time Operating systems, but I'm not sure if I need it to be exactly real time since I can buffer the generated sound data. But I do need the system to be fast, and as light as possible as the sound generation is rather heavy process.
I understand this is sort of vague question and I'm happy with any information I can get and if you could just point me in the right direction, that would be appreciated.
I am wondering if someone have an idea about the range of the wi-pi usb wireless adapter, while I am using it with Raspberry Pi and its transmission power is 20 dBm and working in 802.11b.
thanks!
Highly depends on the environment. In open area with line-of-sight it goes to 100m or even further. In indoor environment, WiFi signal may penetrate only a few brick walls.
My experience with the wi-pi is that it is a pile of junk. I have trouble getting 10m range through one brick wall that other adapters have no problem with. It regularly stops working and requires replugging. Completely unusable.
Imagine I'm standing in a large room that has a router in the corner. Now I'm holding my iPhone and I start moving around in the room.
Is there a way I can track my movement inside that room using as static reference that router?
Imagine I take one or two steps to the left. Will such a small change in location be captured accurately under such conditions?
Do I need more than one hotspots in order to find my precise location inside the room?
Can the tracking be precise since we're talking about movement inside a room and not out on the streets?
If you're interested in tracking physical movement of the phone using a single wireless router as a point of reference, no, it's not going to work. It's defiantly not going to give you a foot or two of resolution, either.
You'd be using the wireless signal strength as a position indicator. However, you'd need two signals (two static points) minimum to give any sort of triangulation. Furthermore, signal-strength triangulation is really, really imprecise - the Wikipedia article gives a network-based tracking a resolution of around 50m. Handset based tracking uses both GPS and signal strength to give a better resolution, but it's still not within a foot or two.
To get good position tracking, a signal is timed between the source and receiver, then triangulated. This gives quite good resolution - Wikipedia articles on "Trilateration", "Time-Of-Flight", and "Multilateration" would give a decent overview of that kind of system.
Long story short? No, you can't get a physical position using a single static router as a point of reference with any degree of accuracy, or precision.
I think you're misunderstanding how Wi-Fi based location tracking works. I'm not sure about the exact process but if I'm right, it involves your IP address assigned by the hotspot you're connected to. And the accuracy of Wi-Fi based location is not as accurate as the degree (a couple of feet to the left or right) you're referring to.
No matter where you are in that room, or even in the same building connected to that same hotspot, your location is going to be reported as the same place.
So to answer your question, NO, the tracking cannot be precise. If you're using you're using the GPS component of your device, that's a totally different story.
Being a bit more specific: I would like to know whether there's a Smartphone that can detect an RFID tag from few feet away using its original HW (no external devices) and OS capabilities.
Any comment/direction to reading material will be highly appreciated.
I think the answer depends on your use of the word "RFID Tag". In the classic sense, a read-only transponder, equivalent to a bar code, the answer is not yet. There are proposals for 2.4 GHz RFID that could use existing WIFI chipsets to identify nearby objects. Nothing standard or accepted is available.
However, based on the application you describe. One potential answer may be to flip how you are thinking of setting this up. If you just need to know if a certian, unique, person is near a spot in the mall, maybe instead of their phone looking for an RFID tag you need a low cost bluetooth sniffer (connected to a low cost computing board) looking for their phone, via bluetooth MAC addresses, within say 5m. As long as the customer has bluetooth enabled, has signed up for your service and your read points are connected to the internet this approach should cover your use case.
Basically the possibility is very low.
Near field refers the the property of RF fields with very close proximity between the devices. In the case of NFC as it applies here the devices are even closer, in what is termed the "Reactive near-field". Moving further away these properties are lost.
From Wikipedia: "Theoretical working distance with compact standard antennas: up to 20 cm (practical working distance of about 4 centimeters)"
I just found this solution:
http://www.ugrokit.com/
I don't have any experience with it.
Any android device with NFC chip and antenna embedded is capable enough to read RFID tags.