Questions tagged [communication]

Exchange of information between devices. Communication can be wired or wireless.

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4
votes
2answers
5k views

Digital input to mobile phone headset port?

This seems to be a common smartphone project, but I haven't seen circuit diagrams with explanations. What filter network (or resistor network, or other buffering circuitry) should be used to connect ...
1
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2answers
787 views

Cheapest way to communicate with a Fez Panda II (or Arduino board)?

I have an application where I will have 30 Fez Panda II boards connected together. They will be spread out over an area of about 100' x 150'. I prefer TCP/IP communciation, but adding a FEZ Connect ...
40
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2answers
12k views

Why are USB devices slower than 480 MBit/s

Motivation With a signaling rate of 480 MBit/s USB 2.0 devices should be able to transmit data with up to 60 MB/s. However today's devices seem to be limited to 30-42 MB/s while reading [Wiki:USB]. ...
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2answers
4k views

What is speed of email? [closed]

I want to know how can we calculate speed of email. I guess that won't be same as speed of electricity or baud rate. I think it gets more complicated considering data doesn't travel in just one ...
8
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3answers
9k views

Using a LED to transmit data

I am curious about the possibilities offered by LEDs to transmit data over a short range (2 or 3 meters), and what maximum data transmission rate can be expected from carefully chosen, but consumer-...
1
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2answers
613 views

Cheapest way to do an IR re-transmitter (IR protocol agnostic, dumb device is good enough)

Looking out for ways to retransmit IR, bi-directionally, like this: ...
0
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1answer
528 views

Communication between modules over USB using a uC

I have a module (say A) which sends data serially to me at 5 Mbps. I want to transfer this data to another module (say B). For B, I have a few choices for links: USB, UART, PCI/E, etc. I am not sure ...
3
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2answers
1k views

Microchip PIC24F & Android device: Which can be host device?

I work on a project where I want to connect PIC24F (Accessory Development Kit for Android www.microchip.com/android) and Samsung Galaxy S2 that I updated from android 2.3.3 to android version 2.3.4. I ...
4
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4answers
617 views

Differential Binary PSK (Phase Shift Keying) based UWB (Ultra wideband) communication

I am trying to create a circuit which can perform wireless communication over short ranges (less than 10 metres) at a very high data rate (approx 10 Mbps) and low power (in the range of 10-20 mW). ...
3
votes
3answers
2k views

Data over power line in a car

I am trying to build a communications system for a car, for turning gadgets on or off. One idea was to parasite on power lines, but what kind of components and signaling could be used for this? I am ...
5
votes
3answers
322 views

Cross-CPU Communications

So - I have a little situation. I have a MC68000 as my system's main CPU, and a 68008 as my sound CPU to interface with a YM2612 and my RGB video generator. Right now, I'm just going to stop the sub ...
4
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1answer
1k views

What is Telemetry?

What Is telemetry? I understand that telemetry is used for measuring, transmitting and receiving. I have two questions: Is my assumption correct or not. Where is telemetry used and what is its main ...
3
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2answers
14k views

I want to build a Frequency Modulation circuit

Does anyone have a simple circuit design that can implement Frequency Modulation or even Amplitude Modulation?
5
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6answers
6k views

How can I make a device that will remotely disconnect an Ethernet port?

In some environments it can be helpful to have the ability to turn off an Ethernet port remotely. One case of this is in a public building where you might have a computer kiosk using the port once a ...
9
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4answers
2k views

What is a good communicaton device among teensy and arduino besides “XBees”

I have been using XBees to communicate my teensies so far. However, as you know, XBees are really expensive and when I want multiple devices to communicate with each other, I have to pay for several ...
1
vote
1answer
505 views

What is an INTERLOCK in J1939?

Hai I'm doing the project on J1939 Periodic Group Broadcast (PGB) protocol. I had an document where it mentions the word "INTERLOCK". I didnt get what is an INTERLOCK,First INTERLOCK,Second INTERLOCK ...
0
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1answer
415 views

Which device amplifies the optical signal in fiber optics?

My teacher ask me one question. How the optical signal or information was transfered in fiber optics communication? Then i explained it and use the word optical amplifier then teacher ask me what is ...
186
votes
8answers
31k views

Why does USB have 4 lines instead of 3?

USB specifies 4 pins: 1. VBUS +5V 2. D- Data- 3. D+ Data+ 4. GND Ground Why is this not 3? Could the Data and Power not share a common ...
3
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5answers
525 views

How does Near Field Communication protect from unwanted long-distance communication?

According to Wikipedia Near Field Communication is intended for short-distance communication - something like less than a meter. I wonder how could this limitation be enforced? Usually there're these ...
7
votes
3answers
785 views

Information content of amplitude modulation versus single-sideband transmission

An amplitude-modulated radio signal with carrier frequency C, which includes frequencies from 0 to F, will use output frequencies in the range C-F to C+F, or a total bandwidth of 2F. A modulation ...
12
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4answers
7k views

Implementing a CAN protocol layer in software

Background I'm developing a project which will require the modest microcontroller specs of: 8 12-bit, 10kHz ADCs 1kB of RAM 48-QFN or smaller footprint 20kbps daisy-chainable noise-resistant and ...
2
votes
1answer
383 views

Shifting Complex Baseband Signal with Pilot Tone

I am trying to shift a complex baseband signal. To do that, I am multiplying by \$e^{(j \times 2 \times \pi \times f_c \times t)}\$, where \$f_c\$ represents the shift amount. The baseband signal has ...
1
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2answers
1k views

Arduino(Nano) Low hertz communication (sound)

I'm thinking about having two arduino's(nano) communicating with eachother, but I'm not 100% sure how. So I was thinking about the ways that are possible: Radio Visible Light Sound Wi-Fi 3G And I ...
2
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5answers
541 views

GPS and Communication (802.11, BT, GSM/GPRS, etc.) ICs

I'm trying to do the preliminary proposals for a small, low power, low cost unit that is capable of reporting it's location to a central service. These devices will generally be in a small urban area,...
1
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4answers
2k views

Connecting LED to RO pin of RS485 Transceiver

I am using this RS485 transceiver in a circuit of mine and I'd like to place a tiny 0805 LED in series with a 1k resistor coming off of the RO (receiving) pin. I'm hoping this would result in ...
2
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5answers
2k views

Recommened chips for datacommunication over a low-voltage AC power line?

A client wants to send data (think 100 ... 10k baud) over a combined power / cable-TV coax cable, distances up to 1 km. The lower end of the spectrum (say up to a few MHz) is free, but the cable ...
15
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6answers
8k views

Wireless communication between more than two Microchip PIC microcontrollers

I would like to create wireless communication between Microchip PICs for my simple project. It's actually an one way communication but there is one server and more than one client (about 2-4, all ...
8
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3answers
903 views

Rather complicated sensor network

I was working on a project recently and it was the first one which was involved enough to make the sensor networking complicated. In the end, I think the communication was the bottleneck in terms of ...
4
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1answer
193 views

Modulation And Other Communication Terms

Could somebody explain the concept of modulating a signal? It's such a broad term I never really understood what it meant. Are phase shift, frequency modulation, and amplitude modulation all ...
1
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1answer
2k views

Arduino Serial communication troubles

I'm having problems getting my communication code to work. I enter the data 1, 0, 255, 50 and then it errors (shouldn't it wait until 8 bits have been sent?) it exits with my debug message of ...
3
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1answer
735 views

How do quarter wave antennas work?

I'm wondering how quarter wave antennas mimic half-wave antennas by using the ground plane. I haven't touched these subjects in a bit, but here are my thoughts: How does the mirrored return ...
7
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3answers
8k views

What does the “posted” mean in posted PCIE transaction?

What is the etymology of the word "posted" in "posted PCIE transaction"? I've worked with PCIE and I understand the difference between "posted" and "non-posted" PCIE transactions, but I don't ...
4
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3answers
2k views

MRF49XA Microchip Transceiver

Does anyone have any experience with the Microchip MRF49XA sub 1GHz transceiver? I have been trying to get one of these to talk to a pic16f886 over the last week or so over SPI and having no luck ...
4
votes
2answers
256 views

How can I add ECC to my packets?

I have been looking into using LDPC's in some of my projects and have had some questions come up. Currently my structure looks something like this: I am then able to have hardware wake when it sees ...
0
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2answers
608 views

Arduino Nano usage

I felt for getting a new hobby. I was thinking about controlling an Arduino through the Internet, and I'm not really sure yet how I'm supposed to do that. I was thinking about connecting it to a ...
0
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2answers
471 views

DB9 Serial communication

I am getting some strange character displays on hyper terminal, after establishing communication with my GSM modem using the appropriate baud rate. When I type "AT", it appears to get repeated or ...
4
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4answers
6k views

uart communication protocol

I'm working on a project where I have to communicate different lengths command from my PC to a microcontroller. (using usb to uart bridge) I already make a litle protocol (start byte, some data, ...
5
votes
1answer
1k views

connect my rc car controller with my computer

I am new to hardware. For my first project, I want to connect my RC car controller with my computer so I can control my RC car in my PC. What kind of things (hardware, cables, tools, as well as ...
3
votes
1answer
948 views

What are the practical implications of changing the rolloff factor of a root-raise cosine filter?

This is in regards to digital communications. I have a link I've set up using GNURadio that's sending BPSK modulated data through water via a LED. I can control the roll-off factor, $\beta$, of the ...
1
vote
2answers
636 views

Books on line codes?

Would you recommend any good book dealing with line codes (i.e. http://en.wikipedia.org/wiki/Line_code). I mean a book that goes a little bit deeper into properties of each encoding (e.g. spectrum). ...
1
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3answers
2k views

Choosing The Right IR Emitter for a Photodiode

I am working with the following IR photodiode http://www.mouser.com/catalog/specsheets/bpv22nf.pdf However, I am having some trouble figuring out what sort of IR emitter I can use with this. I am ...
3
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2answers
519 views

Recommend a Serial to USB cable/converter that works with modern OSes [closed]

I'm hacking on a board that has an RS232 interface (via a Max232 chip). My new computer doesn't have a serial port, which leaves me using USB. I actually have a Serial to USB cord already, but it ...
1
vote
3answers
2k views

Differential to single-ended conversion - transformer or instrumentation amp?

I need to convert the output of differential output DAC to single ended. It's a 2 Vpp signal with a 1 V common-mode output. The output is 100 ohms. Should I use a transformer or a instrumentation amp. ...
1
vote
1answer
472 views

How should I debug my mbed project?

I'm using an external power source to power an MBED module. I have the UART transfer and receive ports connected to a MAX232 level switcher in order to make the signals compatible with RS232. From ...
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1answer
199 views

Using a laptop to communicate with an MBED module

I'm using an external power source to power an MBED module. I have the UART transfer and receive ports connected to a MAX232 level switcher in order to make the signals compatible with RS232. From ...
3
votes
3answers
2k views

Combine a low power XBee receiver with high power XBee transmitter in a model rocket

Have got some existing low power 2mW XBee series 2 with an Explorer that I've used successfully to communicate between a PC with the XBee Explorer and a remote Arduino based project. I'd now like to ...
1
vote
1answer
299 views

Sparkfun Bluetooth modem

Got a question about the Sparkfun radio modem WRL-08495. A pair of these replace an RS-232 cable, right? simple as that? What if my neighbor also has a pair of these? Is there mutual interference ...
3
votes
3answers
646 views

Doubts on Implementing a Simple Protocol for XBee Comms

A system that I'm developing will use XBee modules for a point to point connection between a micro-controller and a PC. Data will only be sent only in one direction -Micro to PC and at 10-20fps. The ...
7
votes
3answers
1k views

Connecting two phone handsets to talk

I am hacking some old phones into my arduino project. I am currently controlling all of the ringers, dials, and hooks through my board. At a certain point, I would like to connect the two handsets ...
3
votes
1answer
321 views

A low bandwidth mesh network for RC planes

I am looking for suggestions of a low bandwidth (<1 kbps) mesh network which can be implemented between RC model planes. It should be able to communicate over distances of 500m or more, preferably ...