We are going to talk about radio. Go over the basics of radio transmission.
Blinking lights in the xport. When you plugin and you don’t get any cable connected. No link, no lights.
Cold solder is the one that metal is cold and solder is hot, make sure the connection is solid and heat the metal not the solder and hold the solder to the joint and resolder it. High resistor pull ups and pull downs and doesn’t harm the board so if there is not many things you can hook up one. Kati’s problem might be resetting pin is resetting itself so putting a resistor from the switch might help. It could be pc’s usb current is too much and it is resetting the board.
When we are dealing with radio communication there is a lot different things. Bluetooth, zigbee, serial radios.
FM, AM, PWM. Frequency modulation we are changing the frequency, and amplitude modulation we are changing the amplitude. if you are 88.1mhz, it means you are between 88.0-88.3 mhz. you are in a band. Audio is added to waves and called carrier waves and you get the data through that. AM waves are longer than FM. Longer waves mean lower frequency. You can carry less information on them, you cannot carry. In terms of digital it is important, one thing every
ISP cares about is bandwidth. bits per second. with digital data we are sending digital waves on our radio waves. if we got low frequency long wave what;s the maximum frequency we can get on that? Higher the frequency higher the power of the waves.
* The electromagnetic spectrum. Intensity of any wave is proportional to the square of the distance. (logarithmic).
* We are sending all those bits, it is radio. How do we regulate those bits? Ethernet, everyone is picking up other’s bits. switch and hub difference. With the help of the addresser, wifi the same. A header.
RF radios intercepting the wifi connection. IF you are all sharing a same bandwidth you need to structure.
There is way to diffierentiate digital waves, through timing.
radio transmmitters three classes you are dealing trnasmitters receivers and transreceivers. you have to consider this when buying things. transmitter and receiver in pair could be cheaper because you don’t have to regulate them you can separate them. We are setting serial data over radio.
FSK shifting frequency , ASK, OOK. When we are sending data these relate how we put our data on the radio wave. OOK is cheaper because it is on and off.
With the RF radios , you pair them normally, you can send serial over the air only when you plugit off you start to get garbage because receiver still looks for data and interprets some of the air waves so it becomes garbage. He has a processing application to get rid of those. Those are straight serial radios. Write a network stack to handle the network. You cannot do a meshup of networks. You cannot change the frequency. Basic rf pairs. I tend not to use it anymore.
Step up to the next level.
Bluetooth, promi, parallax sell bluetooth radios too. BLueradios os the major vendor. Both of these has network stack on them, just likely to internet. They come with them. They have different levels but same. Bluetooth we have the ability to control not only the serial data, but high data transfer. In the network stack of bluetooth and USB as well, physical layer radio, datalink layer we need something to define bluetooth, ... session layer on.off, presentation appluication layer. it might be as serial port. SERIAL, OBEX, AUDIO. each of those has a different profile. Serial Port Profile. A service Discovery layer, when they connect high, I am bluetooth this is my service I am offering you. Even without knowing what you connected to you know what it is offering you. In the bluetooth proerties there is device services menu. You don’t have to write code for those, they already come with those. He then connected bluesmirf and devices only listed serial. COM0.
Dano is doing a class called rest of you where you deal with bluetooth and java and that could be powerful as well. Bluetooth radio transmits audio, maybe an application where you send audio over bluetooth.
command mode you give commands and data mode you can send data. AT commands used in certain devices. It tends to get reused everywhere. AT in the serial window. You can get different different radios listing through those comands, you can pair with any of those. This could be handy, maybe Faludi made his application likewise too. Sending AT commands and getting data. Bluetooth address.
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ATMD
shifts back to data mode.
Pairing is different from connection, you can dis-pair two devices as well. You can set them up that they connect to certain address. The radio was always in data mode. Blueradios don’t connect directly to Mac, first pair it with your computer and then try to open a port from the bluesmirf.
He doesn’t recommend wireless ethernet embed devices. They are high powered.
