Short range remote. 1

[itsmoked]

I'm considering a product that would need to be completely cordless. It needs to be controllable over a distance of about 30ft. Bi-directional info would be preferred but not absolutely required. Low data rates. Perhaps 300baud would be plenty.

The control unit would be like a typical TV remote. Perhaps smaller.

I really don't want to 'scratch build' the rf stuff nor do the full FCC Monty.

What tech and frequency should I be contemplating?

ISM no doubt, but which.

Got any favorites?



Keith Cress
kcress -

http://www.flaminsystems.com

 

[VEBill]

Instinct might suggest that you just need a very simple transceiver set, but these days it might be better, faster and cheaper to just 'go with the flow' and use something like Bluetooth - in spite of it being massive overkill.

 

[geekEE]

I've used the Nordic Semiconductor (

http://www.nordicsemi.com/)

parts for this. They operate in the 2.4GHz ISM band, which is good for stuff that ships to many other countries. If you're just looking at products for the US, then I think there are other bands that would work.

Glenn

 

[MacGyverS2000]

I'm not really sure how you can get away from the FCC crapola if it's a commercial wireless product. They need to stay in power somehow...

Dan - Owner

http://www.Hi-TecDesigns.com

 

[itsmoked]

Yeah. No I recognize the test requirements what I was meaning was the OTS solutions that have their certs already.

VE1BLL; Yes that might make more sense.

geekEE; Thanks for the link. Looks interesting. It could go international but I'm not sure. I'm a little concerned the 2.4 region is way crowded and could result in issues with phones, et al.


Keith Cress
kcress -

http://www.flaminsystems.com

 

[geekEE]

If it could go international, then I think 2.4GHz might be your best bet. Here's an app note from TI that discusses the various ISM bands and worldwide compliance.

http://focus.ti.com.cn/cn/lit/an/swra048/swra048.pdf

I think the worldwide compliance is one reason that Bluetooth is in that band.

I haven't seen any issues with the Nordic part behaving badly with other 2.4GHz devices. It does some sort of frequency hopping to avoid this. And also, since it's bidirectional communication, you can have ACKs coming back to have a pretty bulletproof comm link.

Glenn

 

[itsmoked]

Thanks for the link geek.

Any experience with how 2.4GHz will punch thru perhaps a wall, ceiling, and a roof?

Keith Cress
kcress -

http://www.flaminsystems.com

 

[benta]

itsmoked, a consortium with some of the major consumer electronic players has been formed to address wireless remote control. Some big semiconductor manufacturers are in there too.
It's based on IEEE 802.15.4 radio tech. (the ZigBee radio part):

http://www.rf4ce.org

Might be an opportunity for you to get a standard product?

Benta.

 

[benta]

Forgot to mention:
Freescale is a player in RF4CE and has offered their protocol for this use.
Go to Freescale's website and search for "Synkro".

Benta.

 

[VEBill]

"Any experience with how 2.4GHz will punch thru perhaps a wall, ceiling, and a roof?"

2.4 GHz is used with BlueTooth and WiFi, so your hands-on experience with these sorts of commercial products will indicate the range and performance you can expect. Obviously the antennas are a huge influence. But 30-feet should be easy, even with built-in sub-optimal antennas and a wall or two.

One thing to watch for is the requirement for leaving the link turned on (as opposed to instant on) and the effect of battery life and/or response time. But a BlueTooth headset for a mobile phone can last for days on a AAA battery.

 

[benta]

Bluetooth is not a good choice, as it takes 3...8 seconds to synchronize to the network after being in sleep mode.
You remark is correct for the headset, but that's because it is running at extremely low power (=short range). The OP wants up to 30 m, which is a different story altogether.

An 802.15.4 radio is much better, it is synchronized within few tens of milliseconds after sleep, which is what you need in a remote control.

Benta.

 

[geekEE]

My experience with the Nordic part is in a remote control for some consumer electronics. It seems to go through walls without a problem. We even tried putting the receiver in a metal filing cabinet and it still worked. I guess the gaps in the cabinet were pretty large for a 2.4GHz wave. We didn't try through a ceiling or roof, although I expect that would work depending on the type of construction.

Glenn

 

[controlsdude]

Sick already invented this device

Sick ISD-300 is an infrared bi directional comm device that communicates over 600 ft. used these on cranes

I have used Ethernet access points in transfer cars and cranes and this has been out for years. This would be an off the shelf access point that communicates to a wireless switch in the ceiling.

Are you reinventing the wheel? What is your niche market?

Reverse engineer other peoples stuff to get an idea and focus on an issue that has not been addressed.

wireless radio website these can get through steel easier than ethernet access points.

http://www.data-linc.com/srmfamily/srm6000.htm

 

[itsmoked]

Thanks controlsdude, but that that stuff looks way too industrial. This is for a $300-ish product.

Keith Cress
kcress -

http://www.flaminsystems.com