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Nurse call system use RF

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letrongdtk4

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Hi all,

i need designed a nurse call system.
Ex: 5 room, 21 bed
- Nurse station : 01
- Nurse present : 01
- Corridor light : 05
- Bed head: 21

(1) I wanted use RF Technologies. But i don't know choose band: 2.4G, 900MHz, 433MHz, .....
(2) I have not solution for the battery

Thanks,
 

The lower the frequency the less "line of sight" is an issue which can be an issue in buildings, especially if they have steel framing. Unfortunately the antenna gets longer the lower the frequency. In the ISM bands the best compromise is typically the 900MHz band. It works well enough in most buildings and the antenna is still compact.

In a multistory building with dense walls (brick, concrete) or steel 158MHz is sometimes used.
 

You will find you need to have different versions for different countries unless you use an international standard like 2.4GHz. However, as has been said, lower frequencies may be more reliable in you application. I believe some portions of the 868MHz band in Europe allow higher power but you will need variants such as 915MHz for other countries such as USA. Also look at the 458MHz ISM band.

Keith
 

Selecting frequency for transmission depends on roughly what range you need to communicate. More the frequency, smaller the antenna and more the range it covers. You may use any battery provided you make suitable circuits to charge it. Backup will highly depend on the circuits consumption and type of battery used.
Cheers
 

Thanks of all,

if i use 433MHz or 915MHz band.
can my system affect other equipment in hospital?
 

Some kid can turn on some low-medium quality Toki-Voki device and block your patient urgent calls.

Buildings such as hospitals, postal offices, police stations,.... should have shielded wired infrastructure.



Best regards,
Peter
 

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