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46  Using Arduino / Networking, Protocols, and Devices / Re: Creating a broad 433mhz "Sniffer" on: June 20, 2014, 05:52:48 am
The transceiver you have is an FSK radio, which means that it will only demodulate data from other similar FSK radios.
There are no particular standards which define how manufacturers transmit their data, so trying to make some kind of universal
decoder is pretty well impossible.
47  Using Arduino / Project Guidance / Re: how to use the arduino uno for controlling light switches on: June 18, 2014, 07:58:52 pm
Another possibility is something like this.
Many of these RC light sockets use a SC2272 or clone decoder, of which there are Arduino libraries to generate
the data format needed.
All you then need is a cheap 433 Mhz ASK Transmitter.
48  Using Arduino / Networking, Protocols, and Devices / Re: 433 MHZ (XD-FST and receiver): Can I use the receiver as a simple on/off switch? on: June 17, 2014, 11:19:55 pm
Use a pair of encoder / decoder chips like SC2262 / SC2272 designed to do exactly what you need.
49  Using Arduino / Project Guidance / Re: 433Mhz transmitter/receiver for Arduino to Arduino communication (1km range)? on: June 15, 2014, 06:30:29 pm
The range of 433 Mhz transmitters is heavily dependant on the terrain between the Transmitter and Receiver, and how much obstruction there is.
Most of the information related to range assumes line of sight conditions , ie nothing in the way .
Going to higher power helps a bit , but not much if the terrain is obstructed.
50  Using Arduino / Networking, Protocols, and Devices / Re: RF transmitter AM or FM on: June 13, 2014, 05:27:49 am
The range of any wireless module is totally dependant on the terrain and the obstructions present between the
The choice of modulation will make little differance.
51  Using Arduino / General Electronics / Re: what is electrical noise? on: June 12, 2014, 01:08:22 am
Impedance is a term which describes what current flows in a reactive load  when its fed with an AC voltage.
A reactive load is one which contains a mixture of capacitance , inductance and  resistance.
Its only applicable in AC circuits, as only in AC circuits can the voltage and the current be out of phase.
Electrical noise is always AC.
There are 3 types of electrical noise.
1/ Thermal noise which exists everywhere and cannot be gotten rid of , unless you own a refrigerator that can achieve temperatures of 0K.
You normally only need to worry about this if you are  building low noise RF amplifiers.
2/ Man Made noise which can be sometimes be reduced or avoided, using filters, shielding etc.
Note, not all man made noise is noise , as to some people its useful data, but to others its noise.
3/ Natural noise, such as caused by natural events such as  lighting bolts ,solar flares etc , cant do much about this.

52  Using Arduino / Networking, Protocols, and Devices / Re: Getting crazy with 434mhz receiver - won't receive... on: June 11, 2014, 06:45:49 pm
Wheres the transmitting code, and the transmitting setup.
You need 2 Arduinos to use Virtualwire,.
53  Using Arduino / Networking, Protocols, and Devices / Re: rf longer antenne on: June 09, 2014, 06:15:54 pm
Antennas need to be resonant at the frequency they are used at , which means the length needs to be 1/4 wavelength long, or an odd multiple of that length.
So an antenna 3/4 wavelength will also work, but wont be any better than a 1/4  wavelength.
Any other lengths will be worse.
17 cm is the optimum length for a 433 Mhz transmitter.
54  Using Arduino / Project Guidance / Re: Confused by softserial on: June 08, 2014, 05:26:32 am
Software Serial disables interrupts when its running, so sending from the hardware serial port to the Software Serial Port will work
but the reverse wont , as the hardware port needs interrupts to be enabled to receive data.
55  Using Arduino / General Electronics / Re: Rechargeable Battery Overheating on: June 07, 2014, 06:21:25 pm
Heres a crude method of achieving what you want.
Connect a 5.6V 3 watt or bigger Zener diode, across the battery terminals, so that the Zener starts to conduct
when the battery voltage get to 5.6 V.
NimH cells can be charged to 1.4 V per cell without them overheating. and 1.4 V is a fair approximation of the battery
fully charged.
4 cells in series = 1.4 X 4 = 5.6 V.
The Zener diode will get warm so you will nead a heatsink of some kind.
56  Using Arduino / General Electronics / Re: Project Battery Drains Quickly on: June 06, 2014, 01:16:08 am
What does the project do?
Without knowing what the power demands are , its impossible to determine how big a battery you will need to last 6 months without recharging.
57  Using Arduino / Project Guidance / Re: Need opinions / suggestions on circuit design on: May 30, 2014, 11:10:36 pm
Your biggest problem will be the design of the switching regulator.
To cover a wide output voltage range at high current such as 10 A is a very hard ask.
The biggest problem is the magnetics and getting the regulator to work properly at a low output voltage
with a high current.
Its these conditions which will cause very high peak currents to flow in the magnetics, and that involves you making sure
that saturation doesnt occurr.
Id start by forgetting the Arduino entirely, and try and design a switching regulator that will do what you want.
58  Using Arduino / Networking, Protocols, and Devices / Re: Apc 220 Wireless module don't working on: May 24, 2014, 07:26:52 pm
Im a bit lost here.
Where is the other radio module.
You need 2 , one to transmit from and the 2nd to receive .
Those modules are 1/2 duplex, they can send or receive , but not do both at the same time.
59  Using Arduino / Motors, Mechanics, and Power / Re: Arduino control mains device on: May 23, 2014, 02:14:40 am
What kind of electric water heater is involved?
If its a hot water system, then the heating elements in these heaters are usually 3600 watts, so you will need
a relay with a 15A rating.
60  Using Arduino / Project Guidance / Re: how to interface RF433mhz modules to arduino on: May 22, 2014, 09:40:36 pm
Simplest way is to use an SC2262 encoder at the transmitting end and a SC2272 decoder at the receiving end.
Just connect the encoder to the transmitter, and the decoder to the receiver, and connect the Arduino to the 4 data output pins of the decoder.
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