See post 22
Really really low to no power = non-active device
Sounds like something for RFID.
avr_fred:
Really really low to no power = non-active deviceSounds like something for RFID.
I know for sure that there is no rfid module or simple ic for a longer range then 5cm, i need more the 2meters
And it doesn't have to be secured or unique, the secured message is transmitted after!
I know my english is bad and i may explained it badly, ask if you didn't undersand anything!
Is it too much trouble to push a button?
jremington:
Is it too much trouble to push a button?
Yes :d
prologikus:
Yes :d
Then use reply #1.
aarg:
Then use reply #1.
Be more detalied... What module should i use? When i hear rfid i'm only thinking of RC522 module that is not what i need from any point of view, if you thought of suggesting it then you should read my post again
the receiver on my keychain can't be a simple, 433mhz module receiver, it's consuming too much power
A more complex receiver will consume more power. Receivers are power hungry.
jremington:
A more complex receiver will consume more power. Receivers are power hungry.
Ye... But there are a lot modern cars and home automation systems that did it.
I'm wondering that this does
LTC5507
I only need to detect a rf signal from 2m with a very low quiescent current so then i can send the true rf message
I'm wondering that this does
jremington:
LTC5507 Datasheet and Product Info | Analog Devices
I know but i still don't understand what it does..
Technical English...
The LTC5507 is a very insensitive, extremely broadband receiver that detects basically all radio frequency signals, from 100kHz to 1 GHz. Your local AM and FM radio stations and cell phone towers will all activate it.
Similar to a "crystal radio".
jremington:
The LTC5507 is a very insensitive, extremely broadband receiver that detects basically all radio frequency signals, from 100kHz to 1 GHz. Your local AM and FM radio stations and cell phone towers will all activate it.Similar to a "crystal radio".
But according to it's datasheet i can adjust the frequency to what i need, right?
The chip is not selective. You can approximately set a lowest frequency to be detected.
prologikus:
Ye... But there are a lot modern cars and home automation systems that did it.
Are there ?
Can you provide us with examples and the details of how much power these receivers use ?
srnet:
Are there ?Can you provide us with examples and the details of how much power these receivers use ?
Some Bmw key have it audi opel but can't find any info about their ics
jremington:
The chip is not selective. You can approximately set a lowest frequency to be detected.
What does this mean? It means that it will active whenever it receives the calculated freq or all the freq that are lower that it?
Is there any ic with a more precise freq range so i can send a random 433mhz signal and wake up the arduino from the key
All frequencies equal to or higher than the lowest selected, activate the LTC5507.
jremington:
All frequencies equal to or higher than the lowest selected, activate the LTC5507.
So for example i'll need a higher freq emitter then 2.4ghz so it won't trigger the arduino on every wifi, is this right?
(other ic)
jremington:
The LTC5507 is a very insensitive, extremely broadband receiver that detects basically all radio frequency signals, from 100kHz to 1 GHz. Your local AM and FM radio stations and cell phone towers will all activate it.Similar to a "crystal radio".
A couple of years ago I built a simple field strength meter using this device. Works on HF and VHF frequencies for me. Drives a fairly large analog meter.
Paul