Go to advanced search

by Hoagie
Thu Apr 17, 2014 11:57 am
Forum: Automation, sensing and robotics
Topic: Extreme Low-Cost 3D Printer
Replies: 10
Views: 8795

Re: Extreme Low-Cost 3D Printer

Type L298N into the ebay search box and it will come up with lots of modules that should drive your stepper motors. I've controlled one of these directly from the Pi GPIO lines and found it works. If you have plenty of time to wait for delivery, they are very cheap directly from China.
by Hoagie
Thu Jan 09, 2014 12:46 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Amplify IR signal
Replies: 11
Views: 3375

Re: Amplify IR signal

My first thought is that transistor is only good for 100mA. IR LEDs need more than that.
by Hoagie
Tue Nov 05, 2013 1:08 pm
Forum: Automation, sensing and robotics
Topic: Control Relay Switches via Android using a Raspberry Pi
Replies: 165
Views: 90683

Re: Control Relay Switches via Android using a Raspberry Pi

If you have Apache installed, can;t you do this as a web page. That way any device with a browser can control it. I control my TV with an iPhone or android tablet using the page in the attached picture.
remote.jpg
remote.jpg (27.92 KiB) Viewed 46983 times
by Hoagie
Tue Nov 05, 2013 12:59 pm
Forum: Automation, sensing and robotics
Topic: Some basic info to get me started please
Replies: 4
Views: 1200

Re: Some basic info to get me started please

To drive a relay with an open collector output, connect the relay between the positive supply and the output. BUT always put a diode in parallel to the relay to conduct from the output to the supply. Normally, the diode won't conduct as the voltage across it is the wrong way, but as the relay is swi...
by Hoagie
Tue Oct 08, 2013 11:59 am
Forum: Automation, sensing and robotics
Topic: What to buildm out of the Pi with a low budget?
Replies: 1
Views: 824

Re: What to buildm out of the Pi with a low budget?

I always fancied writing something to fetch information I like to see from various bits of the web and stick it all on one iPhone friendly web page. Hardware cost is roughly 0 if you already have a wireless internet router, which I expect you do as you were able to post on here. You can expand on it...
by Hoagie
Tue Oct 08, 2013 11:48 am
Forum: Automation, sensing and robotics
Topic: Could use advice - remote controlled vehicle
Replies: 2
Views: 1243

Re: Could use advice - remote controlled vehicle

Hi, I had a manually controlled rover roving a round a few months ago using the a lego mindstorms set. I used nxt-python-2.2.2 to talk to the nxt brain brick and had a usb web cam for streaming pictures back. The whole thing was run from a web page with big arrow buttons on it. I hooked the mousedow...
by Hoagie
Tue Oct 08, 2013 11:35 am
Forum: Automation, sensing and robotics
Topic: NXT
Replies: 1
Views: 525

Re: NXT

Yes. I used nxt-python-2.2.2 and had a little rover trundling around my kitchen a few months ago. I can't dig much more info out from where I am at the moment though.
by Hoagie
Mon Oct 07, 2013 11:39 am
Forum: Automation, sensing and robotics
Topic: Network stereo alarm
Replies: 2
Views: 1151

Re: Network stereo alarm

Personally, I'd use a HTML interface to the web browser on the phone and keep the alarm side of it entirely on the Pi. Then it's cross platform, Android, IOS etc. Check out cron for running things on a schedule. The command crontab -e allows you to control it. You'll probably want to add a crontab e...
by Hoagie
Sat Oct 05, 2013 10:14 am
Forum: Automation, sensing and robotics
Topic: Controlling my central heating
Replies: 16
Views: 7291

Re: Controlling my central heating

Just a quick mention. Use the room thermostat input, it's the one designed for this kjnd of control.
by Hoagie
Sat Oct 05, 2013 10:02 am
Forum: Automation, sensing and robotics
Topic: splitting voltage to < 3v3 after sensor
Replies: 5
Views: 1138

Re: splitting voltage to < 3v3 after sensor

It sounds like your sensor has an analogue output. The pi doesn't gave analog inputs so you'll probably need an ADC (analig to digital converter) i expect there's plenty of info on them litterdd around the forum.
by Hoagie
Fri Aug 30, 2013 11:55 am
Forum: Automation, sensing and robotics
Topic: Raspberry Pi Keypad Door Lock
Replies: 2
Views: 6560

Re: Raspberry Pi Keypad Door Lock

Do a quick search for Keypads on here, there's a few articles on how to wire them. I have a USB numeric keypad connected to my Pi, but it stops working if anyone presses the Num Lock key on it.

I don't know much about the availability of the actual locking mechanisms though.
by Hoagie
Fri Aug 30, 2013 11:49 am
Forum: Automation, sensing and robotics
Topic: Help with infrared sensor switch
Replies: 7
Views: 3671

Re: Help with infrared sensor switch

A resistor divider is pretty simple. To shift 5V down to 3.3, you'll need something like this... |---------------Sensor Output | | 22kOhm resistor |------------ Pi input | | 33kOhm resistor |------------ Gnd This will give a little under 3.3V for safety, but plenty of voltage to flip the Pi inputs. ...
by Hoagie
Sun Aug 18, 2013 12:52 am
Forum: Automation, sensing and robotics
Topic: ArduinoCommand - Raspberry PI --> Arduino
Replies: 24
Views: 20817

Re: ArduinoCommand - Raspberry PI --> Arduino

Hi,

Those look just like the ones I used. The transmitter is great, but the receiver is not very sensitive.

I found any gpip pin can works fine with these modules, but I worked with custom softwate.

Regards,
Geoff
by Hoagie
Thu Jul 25, 2013 11:47 am
Forum: Automation, sensing and robotics
Topic: Home Automation, live webpage data and backend
Replies: 1
Views: 1344

Re: Home Automation, live webpage data and backend

Hi, I don't know much Python, but it sounds like you may need a separate thread just reading the serial port. then that one could get locked up waiting for data without upsetting the rest of your code. As for the web thing. I'd go for a simple web server that supports CGI. A CGI is any executable pr...
by Hoagie
Tue Jul 23, 2013 11:53 am
Forum: Automation, sensing and robotics
Topic: Home alarm system?
Replies: 6
Views: 4509

Re: Home alarm system?

They seem a bit unusual. Honeywell seem to be about the only people using them.

Is there any way you can connect the Pi into the alarm control panel? I guess you'd need outputs indicating it's armed, and it's triggered.
by Hoagie
Mon Jul 22, 2013 11:50 am
Forum: Automation, sensing and robotics
Topic: Decoding 433.92Mhz
Replies: 17
Views: 11976

Re: Decoding 433.92Mhz

There are a few transmission standards, but the most common one I've seen is compatible with the PT2262 IC. There area a couple of manufacturers, so searching for just 2262 is probably best.
by Hoagie
Mon Jul 22, 2013 11:39 am
Forum: Automation, sensing and robotics
Topic: Home alarm system?
Replies: 6
Views: 4509

Re: Home alarm system?

Hi, Check out this thread... http://www.raspberrypi.org/phpBB3/viewtopic.php?f=37&t=34855&p=296165#p296165 there's an answer for most of your queries in there. And here's a link to some source code to receive the wireless signals, if it looks like you'll be able to. http://www.raspberrypi.org/phpBB3...
by Hoagie
Fri Jul 19, 2013 12:27 pm
Forum: Automation, sensing and robotics
Topic: Decoding 433.92Mhz
Replies: 17
Views: 11976

Re: Decoding 433.92Mhz

I think i got there with a little luck and some trial and error, i assume its due to the timing of my transmitter and the code im using, for every 12bits in my working code, i found 10 bits in the same timescale on the non working code. I had to change, this line of code: sleeptime.tv_nsec = 222000...
by Hoagie
Mon Jul 15, 2013 11:40 am
Forum: Automation, sensing and robotics
Topic: Alarm clock
Replies: 5
Views: 6665

Re: Alarm clock

Check out the crontab command. crontab -e will open an editor with a sample file that allows you to schedule commands. There are command line MP3 player programs available that could be triggered from crontab. The next problem would be how do you switch it off / snooze it. I'm sure you'll be able to...
by Hoagie
Mon Jul 15, 2013 11:32 am
Forum: Automation, sensing and robotics
Topic: IR Transmitter
Replies: 12
Views: 49996

Re: IR Transmitter

I've done some of what you want, so have a little experience here. Driving an IR LED isn't as simple as a normal LED. You'll need a transistor driving the LED as the Pi can't handle that much current. Then there's the issue of software. I'm not familiar with irsend, so I don't know what it can and c...
by Hoagie
Tue Jun 25, 2013 11:53 am
Forum: Media centres
Topic: Convert Mpeg2 to Mpeg4/h.264 [SOLVED]
Replies: 7
Views: 3604

Re: Convert Mpeg2 to Mpeg4/h.264

There are a number of options: HandbrakeCLI - uses ffmpeg internally. Easy to use with a useful range of presets. ffmpeg - ultimate flexibility. Expect to waste the rest of your life figuring out the constantly changing command line syntax and range of options. Produces very good results. mencoder ...
by Hoagie
Mon Jun 17, 2013 11:56 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: 38kHz modulation with GPIO output??
Replies: 6
Views: 4206

Re: 38kHz modulation with GPIO output??

Hi, I've got IR transmitting working - on a revision 2 Pi only though. I use the PCM output, which can send a data stream at much higher frequencies than 38 kHz. I also record the signals using the PCM input. I'm in the process of writing up the project and will post a link when I've finished. Geoff.
by Hoagie
Tue Apr 16, 2013 12:12 pm
Forum: Automation, sensing and robotics
Topic: How to read and store 200 digital inputs
Replies: 18
Views: 3890

Re: How to read and store 200 digital inputs

Got to keep this brief. Should have time to elaborate later. One of these 74154 (4 to 16 line decoder) to enable the outputs of 16 banks of these 74561 (dual 4 bit counters) Feed just the MSB of the counter to a pin on your Pi, giving 16 banks of 16 counters = 256 inputs. At 30 pulses per second, ea...
by Hoagie
Mon Apr 15, 2013 11:28 am
Forum: Automation, sensing and robotics
Topic: 3D printer with radial arms
Replies: 2
Views: 4559

Re: 3D printer with radial arms

Could a turntable as the work platform make this even simpler from a hardware perspective, at the expense of more complex software?
by Hoagie
Mon Apr 15, 2013 11:19 am
Forum: Automation, sensing and robotics
Topic: Automating button presses on a circuit board
Replies: 12
Views: 2391

Re: Automating button presses on a circuit board

Go for

A to Pi GND
B,C,D,E through 10k resistors to Pi GPIO outputs.

Go to advanced search