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by Hoagie
Sat Sep 16, 2017 5:42 pm
Forum: Automation, sensing and robotics
Topic: how to set up multitasking
Replies: 18
Views: 742

Re: how to set up multitasking

I skip read the last few posts after reading that it wouldn't shut down anymore. This sounds like you have left the other thread running. I don't know how you can send values between threads in Python, but if your main one can set a flag in the background thread it can use this flag to exit its own ...
by Hoagie
Sun Dec 18, 2016 6:13 pm
Forum: Other projects
Topic: Festive wallboard
Replies: 0
Views: 220

Festive wallboard

Hi, In my office we have a build monitor running on a big TV so we can all see whether our software is broken. It's just running a full screen browser pointing to an internal web server. We decided to make it a bit festive and after many iterations came up with the html and images in the attached zi...
by Hoagie
Thu Nov 03, 2016 8:23 pm
Forum: Other projects
Topic: Raspberry pi to Oculus Rift
Replies: 3
Views: 838

Re: Raspberry pi to Oculus Rift

The older Rifts had HDMI connectors. If this one has, I can't see any reason that the Pi wouldn't show something on it.
by Hoagie
Thu Nov 03, 2016 8:19 pm
Forum: Other projects
Topic: Nextion screen as input for pi?
Replies: 4
Views: 762

Re: Nextion screen as input for pi?

Can you give more information on it. A link or model number etc.
by Hoagie
Thu Nov 03, 2016 8:03 pm
Forum: Other projects
Topic: Pi Zero gadget + Wi-Fi
Replies: 3
Views: 646

Re: Pi Zero gadget + Wi-Fi

I have a Pi zero setup with a WiFi dongle acting as a hotspot. Nothing special, you just need to use a micro to full size usb adaptor. Mine came with one. The wifi is the only way in to mine, nothing elseo is connected. I just tell my laptop, phone or whatever to connect to it's hotspot and access i...
by Hoagie
Sun Oct 23, 2016 12:43 pm
Forum: Other projects
Topic: [Help][First Project] Modify/replace Electric candle melter
Replies: 2
Views: 337

Re: [Help][First Project] Modify/replace Electric candle mel

Hi, I can't think of anything that would limit the temperature for you, but maybe the Pi could sense it and control the heater. You can do all kinds of control algorithms in software and keep it much more stable than a simple on off thermostat too. Some kind of mug warmer maybe the right size. I'd t...
by Hoagie
Sun Oct 23, 2016 7:28 am
Forum: General discussion
Topic: nanosecond
Replies: 30
Views: 3742

Re: nanosecond

I know this is an old thread, but if anyone is still reading it, they may be interested to see that it is actually possible.

http://www.ceirogstudios.co.uk/sol/sol.html
by Hoagie
Sat Oct 22, 2016 6:11 pm
Forum: Other projects
Topic: The Speed of Light
Replies: 6
Views: 923

Re: The Speed of Light

You might find this interesting http://codeandlife.com/2012/07/03/benchmarking-raspberry-pi-gpio-speed/ though not up to date and doesn't include pigpio http://abyz.co.uk/rpi/pigpio/index.html you might find piscope shows you some things too. Also not that the R^2 value is pretty much zero, that if...
by Hoagie
Sat Oct 22, 2016 5:51 pm
Forum: Other projects
Topic: The Speed of Light
Replies: 6
Views: 923

Re: The Speed of Light

Burngate wrote:ok, since time goes faster at the top of a mountain than at the bottom, with that result you should be able to work out your altitude.
My estimate is that you're on top of a high mountain. Very high.
I'd expect most people wouldn't try this unless they were high.
by Hoagie
Sat Oct 22, 2016 3:54 pm
Forum: Other projects
Topic: The Speed of Light
Replies: 6
Views: 923

The Speed of Light

Hi,

I recently decided to try and measure the speed of light directly using a Raspberry Pi. Here's a writeup of the project, including circuit diagrams and source code.
http://www.ceirogstudios.co.uk/sol/sol.html

Hope some of you find it interesting.

Thanks,
Geoff.
by Hoagie
Sat Oct 08, 2016 3:52 pm
Forum: Troubleshooting
Topic: WiFi ONLY works if Ethernet is plugged in
Replies: 45
Views: 18039

Re: WiFi ONLY works if Ethernet is plugged in

Thanks.

Putting the wlan0 section before eth0 sorted this for me too.
by Hoagie
Tue Oct 20, 2015 5:50 am
Forum: Recommended peripherals
Topic: wireless AP with hostapd and realtek chipset (works)
Replies: 40
Views: 88319

Re: wireless AP with hostapd and realtek chipset (works)

Hi,

Has anyone managed to get this working with Rasbian Jessie? I had no problem on Wheezy, but keep getting this on Jessie when starting hostapd.

Code: Select all

nl80211: Could not configure driver mode
nl80211 driver initialization failed.
hostapd_free_hapd_data: Interface wlan0 wasn't started
Thanks.
by Hoagie
Sat Jan 03, 2015 4:05 pm
Forum: Advanced users
Topic: make backup dd image while pi is live
Replies: 8
Views: 12374

Re: make backup dd image while pi is live

An interesting (well I like it) side effect of saving an image to a network location, is that you can mount it and read files from it, almost as if it was a real card plugged into the pi. It's easier to do if you only image the partitions and not the whole card, but it's still possible with a card i...
by Hoagie
Thu Apr 17, 2014 11:57 am
Forum: Automation, sensing and robotics
Topic: Extreme Low-Cost 3D Printer
Replies: 10
Views: 5345

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: 1898

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: 139
Views: 39201

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 28332 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: 783

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: 570

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: 949

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: 301

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: 850

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: 5009

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: 624

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: 5225

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: 2263

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. ...

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