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by abishur
Mon Dec 07, 2015 5:39 pm
Forum: Off topic discussion
Topic: Large, Inexpensive Temperature Display
Replies: 1
Views: 902

Large, Inexpensive Temperature Display

I'm working an a project using some temperature probes and need to display the data locally by the probes. Han anyone personally used a 4 or more digit display ( 2 for the whole number, a decimal point, 2 for the decimal places, plus F or C for degree type) where the characters are around 1" tall th...
by abishur
Wed Aug 26, 2015 2:14 am
Forum: Advanced users
Topic: Progamming Arudino (over USB) with Pi
Replies: 2
Views: 1223

Progamming Arudino (over USB) with Pi

I've set up a pi to program an Arduino that it's also powering over the USB port of the arduino. But I'm having a lot of problems actually getting the pi to reliably upload the program to the arduino, half the time it will error out saying the programmer is out of sync. I've gone through the steps t...
by abishur
Thu Jul 16, 2015 6:43 pm
Forum: Off topic discussion
Topic: Figuring out resistor for 7 segment display
Replies: 3
Views: 1234

Re: Figuring out resistor for 7 segment display

That sounds straightforward enough. Two LEDs in series per segment. For the normal calculations the LED forward current would be 0.015A and the LED forward voltage would be 3.4V. For a 5V supply that gives (5 - 3.4) / 0.015 = 106 Ohms. Something like a 110 or 120 Ohm resistor for each segment shoul...
by abishur
Wed Jul 01, 2015 4:30 pm
Forum: Off topic discussion
Topic: Figuring out resistor for 7 segment display
Replies: 3
Views: 1234

Figuring out resistor for 7 segment display

I'm trying to figure out something here. I've purchased some 1" 7 segment displays, that I'll be powering them off 5v. Looking up the datasheet , it shows that each LED segment is driven by 2 LEDs for a max current PER SEGMENT of 15 mA. I can easily understand that when the specs say there is 3v4 to...
by abishur
Tue Jun 30, 2015 5:29 am
Forum: Automation, sensing and robotics
Topic: Help with external ADC and thermistor
Replies: 15
Views: 6377

Re: Help with external ADC and thermistor

Aha! That did the trick... mostly in the end for some reason I had to take my Wheatstone Bridge apart and reassemble it (on a breadboard so not a whole lot of time to do so :lol: ) before I started getting a reading of almost exactly 10K off my resistors, then I swapped it out for my thermistor and ...
by abishur
Tue Jun 30, 2015 2:44 am
Forum: Automation, sensing and robotics
Topic: Help with external ADC and thermistor
Replies: 15
Views: 6377

Re: Help with external ADC and thermistor

I did chat on a post about Steinhart-Hart equation. https://www.raspberrypi.org/forums/viewtopic.php?p=491411#p491411 I have to beg forgiveness on this one, but I've been working on this for several days and my eyes are going cross looking at a giant wall of text :oops: TL;DR, what was the equation...
by abishur
Tue Jun 30, 2015 1:57 am
Forum: Automation, sensing and robotics
Topic: Help with external ADC and thermistor
Replies: 15
Views: 6377

Re: Help with external ADC and thermistor

Question 2: Zero is definitely equal to zero volts (my ground), but what is the 65535 value? Does it equal the 2v048 I'm supply to the voltage dividers or is it the 5v I'm using to supply the ADS1115? I did check the specification of the ADS115. It is 16 bits but one bit is the sign. (second comple...
by abishur
Mon Jun 29, 2015 10:00 pm
Forum: Automation, sensing and robotics
Topic: Help with external ADC and thermistor
Replies: 15
Views: 6377

Re: Help with external ADC and thermistor

Okay, that's fine and all, but once i get a reading I'll have the exact same problems. Can you answer any of the three questions i posed a couple posts back?
by abishur
Mon Jun 29, 2015 7:44 pm
Forum: Automation, sensing and robotics
Topic: Help with external ADC and thermistor
Replies: 15
Views: 6377

Re: Help with external ADC and thermistor

I'm using resistors and thermistors with +/- 0.01% accuracy not +/-0.5%
by abishur
Mon Jun 29, 2015 6:22 pm
Forum: Automation, sensing and robotics
Topic: Help with external ADC and thermistor
Replies: 15
Views: 6377

Re: Help with external ADC and thermistor

Maybe the issue is I'm not understanding how the ADC is actually working so let me try asking three other questions and we can work back to the main issue. I power the ADS1115 from the 3v3 rail. Also being powered off the 3v3 rail is an LM4040 shunt voltage reference. I give it 3v3, it gives a stead...
by abishur
Mon Jun 29, 2015 4:03 am
Forum: Automation, sensing and robotics
Topic: Help with external ADC and thermistor
Replies: 15
Views: 6377

Re: Help with external ADC and thermistor

It's a voltage divider.
by abishur
Sun Jun 28, 2015 9:37 pm
Forum: Automation, sensing and robotics
Topic: Help with external ADC and thermistor
Replies: 15
Views: 6377

Re: Help with external ADC and thermistor

I think I'm on the right track, I found the following formula Rt = (Rs)(Vin - Vout)/(Vout) Where Rt is the Resistance of the thermistor, Rs is a fixed resistor value (10K for me), Vin is the measurement of my analog input, and Vout is the voltage being supplied as my voltage reference. Can anyone co...
by abishur
Sun Jun 28, 2015 9:12 pm
Forum: Automation, sensing and robotics
Topic: Help with external ADC and thermistor
Replies: 15
Views: 6377

Help with external ADC and thermistor

Hi all, I'm trying to read a thermistor using an external ADC with 16 bit precision, the ADS1115. Accuracy is important to me so I've also employed an LM4040 to provide a very steady voltage, specifically I used the model that is supposed to take a 3v3 input and give a 2v048 output. My main issue he...
by abishur
Tue Jun 23, 2015 4:54 pm
Forum: Off topic discussion
Topic: Water proofing electronic components
Replies: 4
Views: 3173

Re: Water proofing electronic components

Search for 'potting compound', used to protect electrical devices and connections er... quite so? As I said I plan on putting on a thin layer of epoxy (potting compound if you prefer) but am looking for specific epoxies people have use and am especially interested with any thoughts on tackling the ...
by abishur
Tue Jun 23, 2015 3:57 am
Forum: Off topic discussion
Topic: Water proofing electronic components
Replies: 4
Views: 3173

Water proofing electronic components

Hi all, I'm working with some thermistors and wanted to make them safe for permanent water submersion up to 10 feet. I was going to use some adhesive shrink tubing rated for marine use on the leads, and use either direct burial ethernet or direct burial sprinkler wire to connect to them. I am going ...
by abishur
Wed Mar 18, 2015 3:32 pm
Forum: Media centres
Topic: Raspberry PI 2 Media Center
Replies: 7
Views: 4404

Re: Rasbery PI 2 Media Center

Hopefully someone with some more specific knowledge than me can fact check this, but in theory you could have both tablets open a video stream and then use VLC on the Pi to load specific videos into that stream.
by abishur
Mon Mar 16, 2015 2:54 pm
Forum: Networking and servers
Topic: Personal Cloud Server: Raspberry pi 2
Replies: 12
Views: 9739

Re: Personal Cloud Server: Raspberry pi 2

Mod Edit: Merged duplicate topics
by abishur
Thu Mar 12, 2015 7:52 pm
Forum: Off topic discussion
Topic: RIP Sir Terry Pratchett
Replies: 15
Views: 3554

Re: RIP Sir Terry Pratchett

Wow, that's quite a blow, he was one of my favorite authors.

And yes, Dougie, you should absolute read some of his books!
by abishur
Wed Mar 11, 2015 6:25 pm
Forum: Off topic discussion
Topic: Need help using Picamera on Mac
Replies: 6
Views: 3624

Re: Need help using Picamera on Mac

Mod Edit: Changed name of thread to something useful
by abishur
Wed Mar 11, 2015 6:23 pm
Forum: Media centres
Topic: Stream library to outside network
Replies: 2
Views: 1248

Re: Stream library to outside network

I think plex can do this?

check out this post, the user seams to indicate that he can stream content to his iPad while traveling

http://www.raspberrypi.org/forums/viewt ... ad#p715646
by abishur
Wed Mar 11, 2015 6:19 pm
Forum: Media centres
Topic: Logitech Harmony POWER
Replies: 1
Views: 1068

Re: Logitech Harmony POWER

Is it currently powering off your pi or is this just a general concern? Also how do you have the harmony remote sending input to the pi?
by abishur
Wed Mar 11, 2015 6:18 pm
Forum: Media centres
Topic: OSMC Rainbow Box
Replies: 8
Views: 6815

Re: OSMC Rainbow Box

I'd also suggest going with OpenElec. OSMC is very much in alpha and you're going to find more pitfalls with any alpha or beta release than you're probably wanting to deal with. OpenElec on the other hand provides just as much functionality as OSMC, which as far as I can tell is the same version of ...
by abishur
Wed Mar 11, 2015 5:14 pm
Forum: General discussion
Topic: Need help with RaspBMC
Replies: 17
Views: 3549

Re: Need help with RaspBMC

The version of Openelec is basically just a port of XMBC (Kodi) to the Raspberry Pi. If you want to watch MPEG-2 (which is the default codec for over the air broadcasts and many TV tuner cards) or VC-1 (which is a Microsoft codec?) videos then you need to swing by the pi store and purchase an MPEG-2...
by abishur
Mon Mar 09, 2015 5:39 pm
Forum: Media centres
Topic: MPEG2 Codec for multiple Pi's?
Replies: 2
Views: 1399

Re: MPEG2 Codec for multiple Pi's?

Yes, you must buy one MPEG2 license per pi, there is no way to transfer them between Pis as the key is tied in some manner to the SOC
by abishur
Mon Mar 09, 2015 4:09 am
Forum: Media centres
Topic: Pianobar not running - no TLS error just failing to load
Replies: 4
Views: 2052

Re: Pianobar not running - no TLS error just failing to load

I got pianobar working without the need for a TLS certificate in the config file. I posted the steps I took here. http://home.comcast.net/~khaas15/Pianobar.htm The most important step in your instruction was to install pianobar from this location git clone https://github.com/PromyLOPh/pianobar.git ...

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