Hello Dennis, Seth here, again. Thank you again for all this info. I will look into it. It may take me a while to reply next time. I need to order some POTs and try the task at hand.
Seth P.S. I could have burnt it out a while back on the TMP36. I will try a different pin too. I should be able to get back to you on the different pin soon. On Sunday, July 9, 2017 at 10:21:36 AM UTC-5, Dennis Lee Bieber wrote: > > On Sat, 8 Jul 2017 18:22:41 -0700 (PDT), Mala Dies > <[email protected] <javascript:>> declaimed the following: > > >Hello Dennis, > > > >Seth here. Thank you for all that info. I will look further into the > >specification sheet on this particular product. Now, I know this is not > >your issue but here goes... > > > > Mostly I ran through all those equations to confirm what might be > happening; I'm not certain I even own a TMP36 in the back corner (my > apartment is a mess and I have to dig just to get to the > BBB/RPi/Arduino/TIVA/etc. stuff). > > There was also that matter where someone recommended that factor > of > 4096 was needed -- but I have trouble believing two books, both using the > same sensor and bonescript, could overlook such a factor. > > Compounding that, is an old report > https://github.com/jadonk/bonescript/issues/39 that says the version of > bonescript on the old Angstrom OS already scaled the analog reading into > the 1.8V (well, 1800mV) range -- so the multiplication by 1.8 (or 1800) > wouldn't be needed for them. Yet the documentation at > http://beagleboard.org/Support/BoneScript/analogRead/ (which of about the > same time frame as the other report) states it returns a float between 0 > and 1, where 1 => 1.8V, hence the scaling factor IS needed here. > > I'm tempted to ask you to try > > http://www.toptechboy.com/tutorial/beaglebone-black-lesson-9-reading-analog-inputs-from-python/ > > (which is using a simple potentiometer to set values, and does not use > node.js weird [to me] "everything is an asynchronous callback"). I believe > recent builds of the Debian OS already include Adafruit_BBIO, but if not > it > isn't difficult to fetch. > > Maybe also try using a different Analog input pin. The advantage > to > trying with the potentiometer is that you can easily sweep through the > entire range from 0.0 to 1.8V. If you still keep getting 0.0, then either > you are wired to the wrong pins, the pins are configured for digital (GPIO > 0/1), or you have a faulty ADC [burned out from overload with >1.8V at > some > time -- but without killing the rest of the BBB]. > > Note that the Python version of the TMP36 exercise is on page 102 > of > [Chavan]; [Monk} is only bonescript, so no help > > >I try to finish each book I get, i.e. no matter the changes in the > kernel, > >image, and/or software I use. It is just a hobby for me as of now. I get > >the V and mV difference. I get basic math but I was unaware of the > offset. > >The book, Programming the BeagleBone Black (Monk), stated something > >different. I was not expecting to see my readings as similar values. I > >understand a little more now. > > > > The main problem is that you aren't getting /valid/ readings; and > the > invalid readings are noise close to the point where Celsius and Fahrenheit > scales manage to cross over (-40 is the same temperature in both, but +40 > is a cold day in Fahrenheit, and a deadly heat wave in Celsius). > > Try with a potentiometer (you could even use the same program, > just > pretend the setting is a temperature)... [Use a fixed pitch font to view > diagram] > > > 1.8V ---+ > | > $--- ADC > | > GND ---+ > > (where $ is the potentiometer). With the pot all the way down you should > get "temps" of -50degC, and turned all the way up should get 130degC, > half-way should give 40degC. > -- > Wulfraed Dennis Lee Bieber AF6VN > [email protected] <javascript:> HTTP://wlfraed.home.netcom.com/ > > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/546f57f8-23cf-448f-bf34-c56ef9ed0655%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
