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by grats
Tue Aug 01, 2017 3:54 am
Forum: Advanced users
Topic: how do I read a closed circuit? 12v
Replies: 11
Views: 1790

Re: how do I read a closed circuit? 12v

I might a: float a magnet in the tank and position a reed switch on tempe glass outside or b: use am ultrasonic distance sensor (more likely for me) aiming down from the topic the tank. I *think it should bounce off of water well enough. Maybe test that before you go all in, though. I've done ultra...
by grats
Mon Jul 31, 2017 11:01 pm
Forum: Advanced users
Topic: how do I read a closed circuit? 12v
Replies: 11
Views: 1790

Re: how do I read a closed circuit? 12v

I connect the 12 volt to 1.2k resistor and then A1 and the ground to C2? (for the 12 volt only) and then 8C and 7E for the pi but I think that is wrong because the letters represent something else.. so I am lost there No, you are quite right. That package is a dual opto-isolator and you only need t...
by grats
Mon Jul 31, 2017 10:18 pm
Forum: Advanced users
Topic: how do I read a closed circuit? 12v
Replies: 11
Views: 1790

Re: how do I read a closed circuit? 12v

Hi. Doing this with 12v is probably a good idea over long distances, reading 12v inputs on the pi GPIO is do able you just need to be careful. First way is to use a potential divider circuit using using 2 resistors like this http://i.imgur.com/b58Yv4G.jpg It will work but if a resistor should fail ...
by grats
Mon Jul 31, 2017 8:58 pm
Forum: Beginners
Topic: Excute while loop while running another task concurrently without using sleep()
Replies: 5
Views: 705

Re: Excute while loop while running another task concurrently without using sleep()

Thank you for the reply. I was talking about Python3. But doesn't matter now because I took some bad advice against start a new thread. As it tuens out using a backgroung thread accomplish what I need and I can use sleep(). :) Also to my surprise, threading is not half as complicated in Pythond the...
by grats
Mon Jul 31, 2017 8:51 pm
Forum: Beginners
Topic: apt-get upgrade not working
Replies: 25
Views: 6445

Re: apt-get upgrade not working

DD. No sync. Never used 'sync' before and haven't encountered this error before. I flashed 2 cards last night with 2017-07-05-raspbian-jessie.img. Pi Zero W no errors upgrading. Pi3 outputs 'files list file for package 'raspberrypi-net-mods' is missing final newline'. Reflashing Pi3 with DD & sync ...
by grats
Mon Jul 31, 2017 8:13 pm
Forum: Advanced users
Topic: how do I read a closed circuit? 12v
Replies: 11
Views: 1790

Re: how do I read a closed circuit? 12v

Start with this. Connect two wires to the float switch. At the RPi end connect one wire to a Ground (= 0 volts) on the GPIO header. Connect the other end to the GPIO you are going to use. Connect a 1 K resistor between that GPIO and 3.3 volt pin on the GPIO header. Also connect a 100nF capacitor be...
by grats
Mon Jul 31, 2017 2:48 pm
Forum: Advanced users
Topic: how do I read a closed circuit? 12v
Replies: 11
Views: 1790

Re: how do I read a closed circuit? 12v

The internet is awash with tutorials on connecting a switch to a RPi GPIO. A float switch is just a switch, either normally open (NO) or normally closed (NC). Do NOT connect 12 volts to the switch. Unless you insert a couple of voltage divider resistors that is in the top two list of how to transfo...
by grats
Mon Jul 31, 2017 12:26 am
Forum: Advanced users
Topic: how do I read a closed circuit? 12v
Replies: 11
Views: 1790

how do I read a closed circuit? 12v

I have a raspberry pi A+ controlling 28 relays that run 24VAC solenoids for a decent sized water system over 20 acres. My 2500 gallon water tank feeds into a 1000 gallon mixing tank for nutrients automatically, with a float switch controlling a 40amp AC relay which is controlled by my 12 volts DC.. ...
by grats
Mon Jul 03, 2017 8:22 pm
Forum: Networking and servers
Topic: Wifi Multi-Band Router
Replies: 3
Views: 1339

Re: Wifi Multi-Band Router

First time poster here I know that the RPi is a very powerful little computer. My uncle has been looking at the Linksys AC5400 Tri-Band Router. It runs on the 802.011ac which allows it to do beamforming. What I'm wondering is, is it possible to take an RPi, install a full OS like pfSense or another...
by grats
Mon Jul 03, 2017 8:01 pm
Forum: Networking and servers
Topic: Running multiple pi's on a tractor
Replies: 26
Views: 4794

Re: Running multiple pi's on a tractor

Monkey wrench: Can your alternator handle the amperage? Take for example my car - it has a 110A alternator in it (which is larger than a standard alternator as I own a v8). The battery has 90 minutes 'reserve'. Essentially, if my alternator cannot supply enough current to everything in the car, my ...
by grats
Wed Feb 22, 2017 9:01 pm
Forum: Beginners
Topic: create a bootable usb linux with raspbian headless
Replies: 1
Views: 1451

create a bootable usb linux with raspbian headless

I would normally DD an ISO to a usb drive and run syslinux on it, but that doesn't exist for ARM? How can I create a bootable usb of another linux .iso using raspberry Pi? I can't seem to find any info on loading a bootloader into the first sector of a usb through the raspberry pi, nothing I've trie...
by grats
Wed Feb 01, 2017 8:24 pm
Forum: Troubleshooting
Topic: disable drive check on bootup?
Replies: 0
Views: 272

disable drive check on bootup?

I have a headless pi running for 2 years now in a remote area (not that remote but satellite internet), maybe twice a year the battery dies, when it gets power back it has to have "ctrl+d" pressed because of my /etc/fstab auto mounting an external hard drive.. Is there a way to disable that? It wasn...
by grats
Fri Mar 11, 2016 2:10 am
Forum: Compute Module
Topic: Compute Module memory size is not 4GB, what am I missing?
Replies: 4
Views: 2165

Re: Compute Module memory size is not 4GB, what am I missing

sudo dd if=/dev/zero of=/dev/sdf bs=1M count=4

I'm fairly sure that'll zero.. 4MB total. run it without count

also you're talking about storage space, not memory.. correct?

3.7 seems correct, file systems etc take space an 8GB flash drive is ~ 7.4GB a lot of the time, for example
by grats
Fri Mar 11, 2016 12:45 am
Forum: Troubleshooting
Topic: unable to use my image after expanding directory
Replies: 2
Views: 502

Re: unable to use my image after expanding directory

In the mean time, if you get completely stuck and a precompiled version of ffmpeg including a fairly recent x264, lame libfdk-aac, libaacplus might get you out of a hole, a kindly soul provided us with this last December... https://www.raspberrypi.org/forums/viewtopic.php?p=868677#p868677 Thanks it...
by grats
Thu Mar 10, 2016 10:05 pm
Forum: Troubleshooting
Topic: unable to use my image after expanding directory
Replies: 2
Views: 502

unable to use my image after expanding directory

So I have one pi I use for testing & programming whom I've used parted on to push the 7gb partition down to 2gb I image it using dd I then can boot into imaged sd card on a different pi as soon as I expand the file system I get ssh: connect to host 192.168.1.78 port 22: No route to host constantly, ...
by grats
Sun May 24, 2015 8:25 am
Forum: Python
Topic: GPIO "channel is already in use" question
Replies: 7
Views: 68475

Re: GPIO "channel is already in use" question

gordon77 wrote:
grats wrote:I'm well aware what's going on, thanks.
Just add. GPIO.setwarnings(False) to your code
So the answer to my question is "yes" this is something I'll have to just deal with

thanks
by grats
Sun May 24, 2015 7:43 am
Forum: Python
Topic: GPIO "channel is already in use" question
Replies: 7
Views: 68475

Re: GPIO "channel is already in use" question

I'm well aware what's going on, thanks.
by grats
Sun May 24, 2015 7:02 am
Forum: Python
Topic: GPIO "channel is already in use" question
Replies: 7
Views: 68475

GPIO "channel is already in use" question

So I'm doing simple turning on/off LEDs I have about 50 lights hooked to relays. Anyway I have an on and off script per relay, everything works fine.. I am wondering about the error: goff.py:5: RuntimeWarning: This channel is already in use, continuing anyway. Use GPIO.setwarnings(False) to disable ...
by grats
Mon May 18, 2015 1:43 am
Forum: Networking and servers
Topic: Host web apps on multiple pi's
Replies: 4
Views: 1515

Re: Host web apps on multiple pi's

setup nginx as a reverse proxy for all of your apps and push them each to different pages or sub domains.
open port 80 to host outside of your house, it'll just be your external ip you go to
by grats
Mon May 18, 2015 1:36 am
Forum: For sale
Topic: Waterproof case?
Replies: 31
Views: 48070

Re: Waterproof case?

capped PVC pipe with wires needed ran through a drilled hole and silicone to seal it.. works fine for me have one under a pond for 2 months
by grats
Mon May 18, 2015 1:33 am
Forum: Wanted
Topic: Pi wireless web server
Replies: 12
Views: 20325

Re: Pi wireless web server

don't use apache for anything, ever. especially the pi.. as it loads required serverside memory child process per session connected. Even when event-based it performs subpar. Use nginx or nearly any other webserver that exists and you'll get a very light event-based web server. I can handle hundreds...
by grats
Tue Mar 31, 2015 11:25 pm
Forum: Camera board
Topic: Pure Python camera interface
Replies: 462
Views: 168030

Re: Pure Python camera interface

Is there a way to have annotate_text run and update its time while the video is recording? is there a "while is_recording" or something? I couldn't find anything.. This is the first time I've used python as well. import picamera import datetime as dt #640x480 90fps #1280x720 60fps #1920x1080 30fps ...
by grats
Tue Mar 31, 2015 9:54 am
Forum: Camera board
Topic: Pure Python camera interface
Replies: 462
Views: 168030

Re: Pure Python camera interface

Is there a way to have annotate_text run and update its time while the video is recording? is there a "while is_recording" or something? I couldn't find anything.. This is the first time I've used python as well. import picamera import datetime as dt #640x480 90fps #1280x720 60fps #1920x1080 30fps v...
by grats
Tue Jun 10, 2014 11:36 pm
Forum: Camera board
Topic: Motion - MMAL camera
Replies: 472
Views: 384485

Re: Motion - MMAL camera

How to install ? Do I have just to replace the standard /usr/bin/motion executable by the one you provide ? Thanks in advance. yes apt-get update apt-get install motion apt-get install -y libjpeg62 libjpeg62-dev libavformat53 libavformat-dev libavcodec53 libavcodec-dev libavutil51 libavutil-dev lib...
by grats
Sun Jun 08, 2014 9:10 pm
Forum: Wanted
Topic: Seeking dev of RPi device for classroom
Replies: 3
Views: 1813

Re: Seeking dev of RPi device for classroom

I would say you are fine with the raspberry pi to do all of that actually the hardest thing to do there is "* Provide an interface (button push) to stop the above sound and light signals" which isn't even that difficult.. just compiling nginx and php-fpm on a pi you'd probably take like 10mb of ram ...

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