[Tinyos-help] Analog signal transfer

[Michael Schippling]

I'm cc'ing this to the help list to keep a record of everything...

By "digital signal" I assume you mean a single bit On/Off thing.
The lowlevel way is to use something like this:

// name an I/O pin -- e.g., port C bit 0
TOSH_ASSIGN_PIN(MOTOR1DIR, C, 0);	// PC0
// Set pin direction
TOSH_MAKE_MOTOR1DIR_OUTPUT(); // or
TOSH_MAKE_MOTOR1DIR_INPUT();
// set value
TOSH_CLR_MOTOR1DIR_PIN(); // 0
TOSH_SET_MOTOR1DIR_PIN(); // or 1
// get binary value
din = TOSH_READ_MOTOR1DIR_PIN();

But there are advanced software modules to do similar on various
platforms and TOS versions. The tmote has:  MSP430GeneralIOM
but I don't know about others.

MS

Abdullah Kadri wrote:
> Thank you very much for this wonderful information. I've already started
> reading the tutorial few weeks ago and still learning the nesC language. I
> think I need to find a way to how to get an analog signal at the second end.
> I believe that I will follow your advice in using PWM and see how it goes.
> Something else, what if I need to send an external digital signal and
> receive it at the second end? Is there an interface for this signal? 
> My questions seem silly but your answer will help me a lot.
> Best,
> 
> Abdullah Kadri, P.Eng., Ph.D. Candidate 
> The University of Western Ontario 
> Department of Electrical and Computer Engineering 
> Phone: (519) 661-2111 ext. 81271
> -----Original Message-----
> From: Michael Schippling [mailto:schip at santafe.edu] 
> Sent: Friday, November 09, 2007 1:19 PM
> To: Abdullah Kadri
> Cc: tinyos-help at Millennium.Berkeley.EDU
> Subject: Re: [Tinyos-help] Analog signal transfer
> 
> If you haven't already, start by reading though the doc/tutorial
> to get an idea what you are up against.
> 
> Then...all mote types have an Analog to Digital Converter (ADC)
> which, conveniently enough, has a range from about 0-3.3v so
> that should cover how to get the data. Look for modules named ADC.
> The Oscilloscope demo app program is, sometimes, a good example of
> collecting and sending data from one or more ADC channels.
> 
> Other examples of sending and receiving are CntToRfm, SenseToRfm,
> and RfmToLeds.
> 
> Now, if you really want an analog signal at the receiving end you
> have fewer options. The telos/tmote controller has an intriguing
> DAC (Digital to Analog Converter) but I've never looked into it.
> The other option is to use a PWM (Pulse Width Modulation) output,
> vary the pulse width relative to the digital value, and integrate
> the result with an RC network. Unfortunately I doubt that either
> the DAC or the PWM features are supported under TOS, so you will
> be doing some low-level controller programming.
> If you are using the mica motes I have some PWM code in:
>      http://www.etantdonnes.com/Motes/AVR128timers.zip
> 
> MS
> 
> 
> Abdullah Kadri wrote:
>>
>> Dear all,
>>
>> I need to send an analog signal from one node to another. I am using two 
>> micaz motes. Can any one send me a brief idea on how to do that? The 
>> analog signal is 0-3 V. Any help will be very much appreciated.
>>
>> Cheers,
>>
>>  
>>
>> Abdullah Kadri, P.Eng., Ph.D. Candidate
>> The University of Western Ontario
>> Department of Electrical and Computer Engineering
>> Phone: (519) 661-2111 ext. 81271
>>
>>  
>>
>>
>> ------------------------------------------------------------------------
>>
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