Wireless hopes and dreams

[russ]

Posted on August 10, 2009 at 13:58

Wireless hopes and dreams

[russ]

Posted on May 17, 2011 at 12:45

I am working on adding wireless functionality to my system. My goal is to find a single-chip rs232 to wireless device to essentially replace my rs232 cable. I know there are bluetooth-rs232 converters out there but they are in the $50 range (a bit expensive for a mass-produced solution).

It looks like most of the chips out there are SPI controlled, but what I am hoping for will use USART or rs232 signal for control and data transmission. Does anyone here have experience with wireless connectivity and transmission of serial datastreams? There is a lot of stuff out there to sort through (and believe me, I am). I am a pretty young engineer and was hoping some of you guys with more experience could point me in the right direction. Thank you. [ This message was edited by: russ1 on 23-09-2008 18:55 ]

[miles]

Posted on May 17, 2011 at 12:45

I've never used any of the ''RF Link''s on this page (scroll down), but they might work for what you want, and they are cheap:

http://www.sparkfun.com/commerce/categories.php?c=79

[russ]

Posted on May 17, 2011 at 12:45

It's funny that you mention Sparkfun. I was just checking out their selection of RF components. There is still a lot of choices. Right now I am leaning towards the Zigbee specification.

If you include Zigbee in your product do you have to pay the Zigbee Alliance Member fee? (~$3000 for the lowest level)

[16-32micros]

Posted on May 17, 2011 at 12:45

Hi ,

You can have a look at these modules from ST-NXP Wireless (now ST-Ericsson) working with Fast RS232 up to 4MHz :

http://www.st.com/stonline/products/literature/bd/14347/stlc2500d.pdf

http://www.st.com/stonline/products/families/communication/wscomm/bluetooth/bluetoothprod.htm

Cheers, STone-32

[jj]

Posted on May 17, 2011 at 12:45

Hi - my firm has used Zigbee - in our opinion it added unneeded cost & complexity.

Before writing - I searched ST site for RF transceiver - found GPS receiver - not what you're seeking. So that said - conscience now clear - check out TI's CC1101. (I am not TI agent) It is hi-performance xcvr (both tx & rx) - but as you said - requires the STM32 to ''talk'' SPI - not uart. This is NOT for hi-qual. audio - but great for instrumentation and ''driving'' the signal the last 100 or 200 feet! (and in TWO Directions - eliminating the dread of ''Send & Pray!'') Importantly demo kits are available - use them. RF is ''black art'' as well as science - we copied board design and are incorporating RF as an option in our new line of colorful, STM32 powered, HMIs. [ This message was edited by: jj.sprague on 23-09-2008 23:24 ]

[st3]

Posted on May 17, 2011 at 12:45

Quote:

I am working on adding wireless functionality to my system. My goal is to find a single-chip rs232 to wireless device to essentially replace my rs232 cable.

Your first task is to define exactly what you mean by ''wireless'' - it covers a vast spectrum of options! Literally, ''wireless'' is anything without wires - so that could include ultrasonic, optical, infrared, etc,...I guess you mean ''RF'' - but that is still a vast field. Do you just want a simple, short-range, low-speed, point-to-point link? Does it need to be standards-based for interoperability? Does it need wide coverage and connectivity - like GSM? Do you require networking - like WiFi or Zigbee? etc, etc, etc,...

[russ]

Posted on May 17, 2011 at 12:45

You are very correct st7. I should have been more specific.

I am looking at options in the realm of RF. Specifically the 2.4GHz frequency because our product is for international use. The wireless connection is point to point as opposed to mesh so ZigBee is not ideal; however, the 802.15.4 specification would be nice because of its inherent reliability and error-checking. Transmission rate: >9600 baud Range: 100m-500m line of sight No standard protocol is required No networking is required

[lanchon]

Posted on May 17, 2011 at 12:45

> Right now I am leaning towards the Zigbee specification... If you include Zigbee in your product do you have to pay the Zigbee Alliance Member fee?

you can use zigbee-capable hardware with a different protocol and software stack to simplify things and avoid costs. both microchip and TI give you such simplified stacks for free (if you use their radios I guess). I'd say most if not all zigbee radio manufacturers will give you some kind of alternative stack (but you'd be glue to them).

[andy239955_stm1]

Posted on May 17, 2011 at 12:45

you can get bluetooth down to around $25/module in volume, but I suggest you look at Nordic Semiconductor's 8051+radio parts, which are a direct competitor of the TI C1101 that someone else mentioned.

I've used bluetooth modules from Roving Networks which work fine, but I have come to hate bluetooth due to the unreliability of the PC end of the software. Module-to-module worked fine. I have used the 900Mhz band parts from nordic and they were quite easy to program for what you want. I chose them over TI because TI wasn't shipping parts when I had to make a choice :)