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61  Using Arduino / Networking, Protocols, and Devices / Re: 315mhz RF to turn on buzzer on: June 28, 2014, 02:46:39 am
Can you explain more in detail what you want.
How is the location of the cat related to the buzzer, or is the buzzer somehow going to be attached to the cat?
62  Using Arduino / Networking, Protocols, and Devices / Re: RF 434Mhz receiver doesn't detect remote on: June 27, 2014, 03:45:47 am
For hacking unknown types of remotes, you really need a scope of some sort, and you need to pull apart the transmitter
to gain access to the data pin of the 433 Mhz transmitting module in the transmitter.
By looking at the data pattern, its sometimes possible to work out the data format, but its usually a time consuming process.
63  Topics / Home Automation and Networked Objects / Re: Arduino Micro & RF Receiver problems on: June 26, 2014, 07:23:38 pm
From the Vellaman Web Site it says
The Transmitter is claimed to be compatable with the following devices.


You will need one of those to correctly decode the transmitters signal, or you will need to hack
the code format the transmitter uses, if you want the Arduino to be able to decode it.
It sounds like the transmitting module is using some kind of proprietary data format.
64  Using Arduino / Networking, Protocols, and Devices / Re: RF 434Mhz receiver doesn't detect remote on: June 26, 2014, 07:10:46 pm
The RC Switch library relies on the transmitting end and the receiving end using a SC2262 / SC2272 data format.
Most remote controlled power points and lights have these chips in them.
If the device you are using doesnt use this data format then the RC Switch library wont work.
65  Using Arduino / Sensors / Re: Improving ADC resolution with Instrumentation Amplifier on: June 24, 2014, 09:08:45 pm
There are opamps which are designed specifically for applications like this.
Have a look at
Its a selectable gain single ended opamp with gain blocks of 10 or 100 , and supports common mode voltages up to 50V
with a 5V supply .
66  Using Arduino / Project Guidance / Re: Capture raw RF 433Mhz signals without sound card on: June 23, 2014, 06:30:24 pm
Its quite common for garage door openers to use 433.92 Mhz , but most of the openers are rolling code transmitters
which means that you cant easily learn the code, as it changes everytime you push the button on the opener.
Making a universal 433 Mhz receiver is pretty impossible as theres no standard as to how the manufacturers of the transmitters  have to encode the data so no way to figure out where the data stream starts and stops.
67  Using Arduino / General Electronics / Re: 433 MHz garage door opener --> hackable? on: June 23, 2014, 07:55:52 am
Many garage door openers use a rolling code transmitter to provide extra security.
if yours does, they arnt hackable.
68  Using Arduino / Motors, Mechanics, and Power / Re: My simple Ni-mh battery discharger mah calculator Arduino project on: June 20, 2014, 05:32:23 pm
Battery capacity is normally specced at the C/10 rate, which means the battery needs to be discharged at a current which is equal
to its mah rating / 10 , so a 200 mah battery would be discharged at 20 ma.
Also , discharging a battery into a resistor wont give a constant current discharge rate , so the result will be slightly incorrect, depending on the resistor value.
69  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.
70  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.
71  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.
72  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.
73  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.
74  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.

75  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,.
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