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by Tarcas
Fri Jul 18, 2014 8:30 pm
Forum: Automation, sensing and robotics
Topic: Programmable thermostat
Replies: 6
Views: 2836

Re: Programmable thermostat

What do you plan on using as a per-room controller? You could simplify things by installing a separate Pi in each room connected to wifi, a DHT11 (Digital Humidity and Temperature sensor) and a relay board. Alternately, a small arduino could read the sensor and trigger the relay on its own, and coul...
by Tarcas
Fri Jul 18, 2014 8:14 pm
Forum: Automation, sensing and robotics
Topic: use existing door hardware for smart lock
Replies: 3
Views: 2092

Re: use existing door hardware for smart lock

I'd recommend an electronic strikeplate. This replaces the strikeplate (and often a small portion of the wall around it) and allows the bolt to slip through when a current is applied. It uses an electromagnet to release, and stays locked in the case of a power failure. The method you proposed, of us...
by Tarcas
Tue Jul 08, 2014 1:16 pm
Forum: HATs and other add-ons
Topic: Powered USB hub that charge my Pi
Replies: 6
Views: 2658

Re: Powered USB hub that charge my Pi

BackPowering is against the USB specification, but many cheaper Mains Powered Hubs do so, I had a backpowering hub and it was not stable. I bought a quality 4 port hub so could power the Pi via the Micro USb, leaving 3 ports free, feel safer knowing that I have a stable and fuse protected power sup...
by Tarcas
Sun May 25, 2014 2:38 pm
Forum: Advanced users
Topic: protection
Replies: 13
Views: 4063

Re: protection

i have an new device i want to make using the PI as the base .. once i setup all the software on the SD card, how can i prevent someone from just copying the SD card and using it on another PI? ... can i encrypt and lock the SD card for use only with one specific PI? ... how can i protect the IP in...
by Tarcas
Sun May 25, 2014 1:37 pm
Forum: Automation, sensing and robotics
Topic: Piston component?
Replies: 4
Views: 3974

Re: Piston component?

Much easier way than the motor-based suggestions above, just use a solenoid. It's an electromagnet with a piston inside, which the electromagnet then moves in a linear motion. For a ping-pong ball, this would probably be sufficient, given a sufficiently-sized solenoid. You'd connect it to the Pi in ...
by Tarcas
Sun May 25, 2014 1:15 pm
Forum: Raspberry Pi OS
Topic: apt-get update problem
Replies: 45
Views: 109820

Re: apt-get update problem

The following is the error I am receiving in running the "sudo apt-get update" command. Err http://mirrordirector.raspbian.org wheezy Release.gpg Could not connect to mirrordirector.raspbian.org:80 (5.153.225.207). - connect (111: Connection refused) Err http://archive.raspberrypi.org wheezy Releas...
by Tarcas
Tue May 20, 2014 2:47 pm
Forum: Raspberry Pi OS
Topic: cannot boot X after adding user
Replies: 9
Views: 1520

Re: cannot boot X after adding user

rPioneer wrote:While I'm in /home/bob/ ? And do you want me to write out all I find, or just if there's an error?
After you run that, look at the output. If it says the files are owned by pi with group pi, you'll need to chown and chgrp them to bob.
by Tarcas
Tue May 20, 2014 2:34 pm
Forum: Raspberry Pi OS
Topic: Automatically restart app after crash in its previous state
Replies: 3
Views: 1941

Re: Automatically restart app after crash in its previous st

I'm not at all familiar with that program, but to do it you'd need a way to read what PDF is open and store that file name so that you can restore it if it crashes. Would grepping the ps list yield that file name? If so, do that every minute or so and save it as a variable that you can use when you ...
by Tarcas
Tue May 20, 2014 1:34 am
Forum: Beginners
Topic: Due to arrive in the next two hours
Replies: 12
Views: 2336

Re: Due to arrive in the next two hours

Video (HDMI and VGA) connectors on laptops are usually OUTPUTS. You can't simply assume that they will also function as INPUTS: this is unlikely to work... I never assume ...but with 3x USB ports they are outputs to my arduino and also inputs, so why not to a Pi. if I can up load to my browser from...
by Tarcas
Tue May 20, 2014 1:00 am
Forum: Beginners
Topic: Need help with turning my raspberry pi into a PID temp cntrl
Replies: 4
Views: 1598

Re: Need help with turning my raspberry pi into a PID temp c

Not sure what thermometer you'd use for 1000 degrees F, but if you can find equipment that works on 3.3v, you can use it with the Pi. Even 5v sensors and devices can work fine using a logic level converter. As for the 1.8" display, Adafruit has a tutorial: https://learn.adafruit.com/1-8-tft-display ...
by Tarcas
Mon May 19, 2014 3:29 pm
Forum: Advanced users
Topic: Controlling 32 lights with the Raspberry Pi
Replies: 9
Views: 4901

Re: Controlling 32 lights with the Raspberry Pi

No, you can't daisy chain a relay board, but what you can use is a GPIO port expander. These can be daisy chained if necessary. I don't know about 32-relay boards, but 4 8-relay or 2 16-relay boards would work just as well. I also don't know about finding a solution prebuilt, but seeing your "ignore...
by Tarcas
Mon May 19, 2014 5:11 am
Forum: Beginners
Topic: Static Ip Problem
Replies: 7
Views: 1363

Re: Static Ip Problem

You have to bring the interface down and back up before it uses the changes in that file: sudo ifdown eth0; sudo ifup eth0 (I'm in the habit of running those two commands on one line after using the former to take down the internal interface of a headless Linux-based router, which was my only method...
by Tarcas
Mon May 19, 2014 4:23 am
Forum: Advanced users
Topic: USBRelay on RaspberryPI
Replies: 15
Views: 8879

Re: USBRelay on RaspberryPI

My first questions is... do you really have a file at usbrelay/usbrelay/.usbrelay? Not a problem if you do, but it causes me to raise an eyebrow, so it might be worth verifying that that's what you meant. Sorry, I'm not sure I have understood. Should I create a usbrelay/usbrelay/.usbrelay directory...
by Tarcas
Mon May 19, 2014 4:13 am
Forum: Automation, sensing and robotics
Topic: Lofty Pi Project with PiFace
Replies: 2
Views: 857

Re: Lofty Pi Project with PiFace

Sorry, I'm not familiar with the Piface, but unless I'm mistaken anything that's not voltage or ground will go to a GPIO pin. Which one depends on software. If you're writing the software yourself, you will define which pin controls what function. Typically you would define these as constants at the...
by Tarcas
Mon May 19, 2014 4:03 am
Forum: Automation, sensing and robotics
Topic: Project to control a 1.6 kW engine
Replies: 3
Views: 880

Re: Project to control a 1.6 kW engine

Is this an electric motor, or a gasoline engine? Engine generally refers to something that burns a fuel and motor refers to something that runs on electricity. If the former, the last post is on target. You'll probably want an H-bridge if you need direction control, and PWM to regulate speed. Is it ...
by Tarcas
Mon May 19, 2014 3:56 am
Forum: Automation, sensing and robotics
Topic: Connect to power socket remote
Replies: 9
Views: 1589

Re: Connect to power socket remote

Sorry, I've just re-read your first post and I see what you mean now. So a solution would be to connect a transistor across button 3 to mimic a button press. I will give that a go... That could work if you tie the grounds together. I'd recommend an optocoupler instead though. That way you can keep ...
by Tarcas
Sun May 18, 2014 10:56 pm
Forum: Advanced users
Topic: USBRelay on RaspberryPI
Replies: 15
Views: 8879

Re: USBRelay on RaspberryPI

My first questions is... do you really have a file at usbrelay/usbrelay/.usbrelay? Not a problem if you do, but it causes me to raise an eyebrow, so it might be worth verifying that that's what you meant. Also I noticed that you're running make install before you run gcc. I'm not familiar with this ...
by Tarcas
Sun May 18, 2014 3:42 am
Forum: Automation, sensing and robotics
Topic: Connect to power socket remote
Replies: 9
Views: 1589

Re: Connect to power socket remote

No problem. Before you watch either of the next videos that I'm going to link you to, you should probably learn about the transistor, but that would be my last choice for hooking this up. Here's part 1 of a 2-part transistor series, which focuses on the Raspberry Pi. Go ahead and watch them both. Ne...
by Tarcas
Sun May 18, 2014 3:31 am
Forum: Automation, sensing and robotics
Topic: use Raspberry as a USB Keyboard
Replies: 13
Views: 4956

Re: use Raspberry as a USB Keyboard

USB would require 2 pins, so no problem at all. Also it is surely possible to emulate USB through GPIO, hence the name general purpose i/o. I see two possible problems: The PI can only pull up to 3V instead of 5V. Also you might run into timing issue when using an operating system. Instead of a Ard...
by Tarcas
Sat May 17, 2014 2:17 pm
Forum: Automation, sensing and robotics
Topic: Automated cat deterrent?
Replies: 3
Views: 2094

Re: Automated cat deterrent?

suicidal_orange wrote: The other ideas would be more fun to make though, just be wary of what will be getting wet if he works out the path of the water and gets out of the way if you go that route.
...or what will get wet and/or knocked over when he DOESN'T get out of the way. :-D
by Tarcas
Sat May 17, 2014 2:14 pm
Forum: Automation, sensing and robotics
Topic: Connect to power socket remote
Replies: 9
Views: 1589

Re: Connect to power socket remote

You'll want to use something like a transistor, relay, or optoisolator to allow the Pi to bridge the connections for the various buttons. You don't want to hook the GPIO directly to the board; you need one of those to act as a switch instead.
by Tarcas
Sat May 17, 2014 3:13 am
Forum: Advanced users
Topic: Using Additional GPIO Pins
Replies: 4
Views: 1107

Re: Using Additional GPIO Pins

You can use any of the 17 green GPIO pins. Also if you solder on the P5 header you can add 4 more (plus another 3.3v, 5v, and 2 GND pins)
by Tarcas
Sat May 17, 2014 3:10 am
Forum: Advanced users
Topic: renaming your username
Replies: 5
Views: 1442

Re: renaming your username

I haven't tried usermod, but you could always useradd a new user and copy over your home directory to that of the new user.
by Tarcas
Fri May 16, 2014 11:39 pm
Forum: Beginners
Topic: Dual-boot making Pi slow
Replies: 6
Views: 1299

Re: Dual-boot making Pi slow

It shouldn't be slower. Each OS should ignore the other.

If you want more space, you could either give each OS its own card, or add a thumb drive to store your files on.
by Tarcas
Fri May 16, 2014 8:56 pm
Forum: Raspberry Pi OS
Topic: Problem with apt-get
Replies: 2
Views: 785

Re: Problem with apt-get

what's in /etc/apt/sources.list

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