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Re: Bluetooth or Other Remote Control Link

Cross-posted to 2 groups.

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On 2/11/2015 7:09 PM, Tim Wescott wrote:
> On Wed, 11 Feb 2015 11:40:27 -0500, rickman wrote:
>
>> A friend has asked me for help with an idea he has which requires a
>> simple RF link to control a 12 volt circuit.  One end of the link would
>> need an MCU to collect the inputs and make a decision about the state of
>> the 12 volt circuit.  The RF link is used to control the 12 volt
>> circuit.  The MCU end would be battery powered and so needs to be low
>> energy.  It is only on with a very low duty cycle, less than a dozen
>> times a day for a short while each time.  There may be a need for a
>> bidirectional link to verify the serial number of the remote unit, I'm
>> not sure.  The range is single digit feet, but there may be metal in the
>> way, similar to a unit under a car hood for example.
>>
>> I was originally thinking of using Bluetooth, BLE specifically.  But I
>> have had some awkwardness with the connection in various uses.  One
>> advantage is that qualified modules are available which get around the
>> FCC certification I believe.  I found the NRF51822 Eval Kit which seems
>> to be a SOC with both Bluetooth and an ARM CM0, not bad but no certs I
>> would assume.
>>
>> If the remote unit does not need to be identified, I would think there
>> are much simpler solutions.  I expect the type of xmit and receive
>> modules used in weather stations might be adequate.
>>
>> Any recommendations for units to consider for a prototype?
>
> Is ZigBee still a viable contender for this sort of stuff?
>
> If it's really under hood, it sounds like (a) a difficult EMI environment,
> and (b) a "whyinhell not just use wired" environment.  But I'm sure he has
> constraints you haven't mentioned.

I don't automatically question all requirements.  If they ask for 
wireless, I'll give them wireless.  I didn't say this would go in a car. 
  I said there might be some level of shielding from metal similar to 
being under the hood, lots of metal, but not shielded like a PC case. 
The distance is short, so a bit of attenuation from a loose case 
shouldn't be a problem.

I don't know much about ZigBee.  I believe it is a lower data rate than 
Bluetooth which would be fine.  The one end needs to be low power and I 
think Zigbee fits that.  I'll do a little digging.  But I think that is 
what BLE is in response to, so there may not be much difference.

One nice thing about Bluetooth is there are a million ways to prototype 
and canned modules with certs are available.

-- 

Rick

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Bluetooth or Other Remote Control Link rickman <gnuarm@gmail.com> - 2015-02-11 11:40 -0500
  Re: Bluetooth or Other Remote Control Link visualforth@rocketmail.com - 2015-02-11 09:46 -0800
  Re: Bluetooth or Other Remote Control Link Paul Rubin <no.email@nospam.invalid> - 2015-02-11 11:21 -0800
  Re: Bluetooth or Other Remote Control Link Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2015-02-11 22:51 +0200
    Re: Bluetooth or Other Remote Control Link rickman <gnuarm@gmail.com> - 2015-02-11 22:12 -0500
  Re: Bluetooth or Other Remote Control Link Tim Wescott <seemywebsite@myfooter.really> - 2015-02-11 18:09 -0600
    Re: Bluetooth or Other Remote Control Link rickman <gnuarm@gmail.com> - 2015-02-11 22:07 -0500
      Re: Bluetooth or Other Remote Control Link Tim Wescott <tim@seemywebsite.com> - 2015-02-12 09:55 -0600
        Re: Bluetooth or Other Remote Control Link Raimond Dragomir <raimond.dragomir@gmail.com> - 2015-02-12 08:44 -0800
        Re: Bluetooth or Other Remote Control Link rickman <gnuarm@gmail.com> - 2015-02-12 15:04 -0500
          Re: Bluetooth or Other Remote Control Link visualforth@rocketmail.com - 2015-02-12 12:39 -0800
            Re: Bluetooth or Other Remote Control Link rickman <gnuarm@gmail.com> - 2015-02-12 17:16 -0500
          Re: Bluetooth or Other Remote Control Link Tim Wescott <seemywebsite@myfooter.really> - 2015-02-12 17:37 -0600
            Re: Bluetooth or Other Remote Control Link rickman <gnuarm@gmail.com> - 2015-02-12 22:32 -0500
              Re: Bluetooth or Other Remote Control Link Tim Wescott <tim@seemywebsite.com> - 2015-02-13 11:18 -0600
  Re: Bluetooth or Other Remote Control Link visualforth@rocketmail.com - 2015-02-13 11:22 -0800
  Re: Bluetooth or Other Remote Control Link Frnak McKenney <frnak@far.from.the.madding.crowd.com> - 2015-02-14 11:50 -0600
    Re: Bluetooth or Other Remote Control Link rickman <gnuarm@gmail.com> - 2015-02-15 21:49 -0500
  Re: Bluetooth or Other Remote Control Link o pere o <me@somewhere.net> - 2015-02-16 09:29 +0100

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