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by aquarat
Wed Sep 04, 2013 8:10 pm
Forum: Automation, sensing and robotics
Topic: Hydrometer Pi
Replies: 2
Views: 2510

Re: Hydrometer Pi

I'm also interested in this... I'm home brewing beer and I'm using a Pi to control the temperature based on data from a set of 1-wire thermal probes. It could be quite interesting to parallel SG to thermal output.
by aquarat
Thu Jul 18, 2013 11:46 am
Forum: General discussion
Topic: SD corruption on power outages
Replies: 8
Views: 4145

Re: SD corruption on power outages

Thanks MattF, that's good advice. My devices can lose changes :) .
by aquarat
Thu Jul 18, 2013 9:28 am
Forum: General discussion
Topic: SD corruption on power outages
Replies: 8
Views: 4145

Re: SD corruption on power outages

I've been having this issue too... usually it's not an issue because I shut down my Pis or I put them on a battery backup, but recently I connected two of them to two LCD displays and the displays are often powered down by accident. I was thinking that making the rootfs read-only and then having a s...
by aquarat
Mon May 20, 2013 3:53 pm
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 123282

Re: NTP PPS

My Raspberry Pi running this NTP configuration has been up 250 days :D .
by aquarat
Thu Dec 06, 2012 10:21 pm
Forum: General programming discussion
Topic: How I compiled MariaDB and Phidget drivers
Replies: 7
Views: 12129

Re: How I compiled MariaDB and Phidget drivers

I just installed mysql... and so far it's working quite well for my project (Power meter reading).
by aquarat
Thu Nov 22, 2012 8:48 pm
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 123282

Re: NTP PPS

Just for those who are asking about a guide / technote / tutorial : I made a post/tutorial on how to duplicate my setup on page 5 of this thread.
by aquarat
Tue Nov 06, 2012 9:01 am
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 123282

Re: NTP PPS

Code: Select all

 11:01:29 up 53 days, 19:39,  2 users,  load average: 1.56, 1.60, 1.82
Image
It's the most accurate time server I've ever had... and it's proving to be very reliable :) .
by aquarat
Mon Oct 29, 2012 6:06 am
Forum: Networking and servers
Topic: APRS tracking mash-up
Replies: 13
Views: 6219

Re: APRS tracking mash-up

Hi Chuck

I didn't realise that, thanks for the explanation @ portA/B. The Pi's UART can only run TTL on 3.3v. It is not over-voltage tolerant, that's why I'm using a MAX232-based converter (which so far has worked very well).
by aquarat
Sun Oct 28, 2012 5:26 pm
Forum: Networking and servers
Topic: APRS tracking mash-up
Replies: 13
Views: 6219

Re: APRS tracking mash-up

Hey Exciton Ah! I honestly had no idea the TT4 had a MAX232(?) in it lol :P I would assume that you have to bypass the chip to use the TT4 with a Pi because the Pi's pins aren't over-voltage tolerant ? sending a RS232 voltage down onto a TTL-Pi pin could damage it ? I worked out what was causing the...
by aquarat
Mon Oct 08, 2012 8:58 am
Forum: Advanced users
Topic: Pool Pump and PWM/GPIO speed control
Replies: 19
Views: 12935

Re: Pool Pump and PWM/GPIO speed control

Thanks for all the advice. I haven't had a chance to work on this, hopefully I'll have time today. I found this document : Ceiling Fan Speed Control - Single-Phase Motor Speed Control Using MC9RS08KA http://i.stack.imgur.com/4s1xQ.jpg The document uses a microcontroller with a lower sampling frequen...
by aquarat
Sat Oct 06, 2012 6:39 pm
Forum: Networking and servers
Topic: APRS tracking mash-up
Replies: 13
Views: 6219

Re: APRS tracking mash-up

Haha, no worries, I'm glad I covered that point :) .
by aquarat
Sat Oct 06, 2012 6:31 pm
Forum: Networking and servers
Topic: APRS tracking mash-up
Replies: 13
Views: 6219

Re: APRS tracking mash-up

mmm... well there are three things, from my experience with the Pi that could potentially cause serial comm issues : (1) The most obvious : are you use a decent TTL -> RS232 level shifter ? http://devrat.aquarat.za.net/assets/aprsPi.jpg http://devrat.aquarat.za.net/assets/ekm/IMG_20120731_092441.jpg...
by aquarat
Sat Oct 06, 2012 5:45 pm
Forum: Networking and servers
Topic: APRS tracking mash-up
Replies: 13
Views: 6219

Re: APRS tracking mash-up

Hi My APRS Pi has been working flawlessly. Here are the major config files on my system : /etc/inittab : # /etc/inittab: init(8) configuration. # $Id: inittab,v 1.91 2002/01/25 13:35:21 miquels Exp $ # The default runlevel. id:2:initdefault: # Boot-time system configuration/initialization script. # ...
by aquarat
Tue Oct 02, 2012 9:12 pm
Forum: Advanced users
Topic: Pool Pump and PWM/GPIO speed control
Replies: 19
Views: 12935

Re: Pool Pump and PWM/GPIO speed control

Hi Gordon I found your wiringPi library when I first started looking for PWM-related stuff. I was/am specifically after hardware PWM (which is available on GPIO18?) because I hoped that 1) it'd provide higher sampling rates 2) it'd be less prone to multi-tasking related timing error and 3) it'd use ...
by aquarat
Tue Oct 02, 2012 5:36 pm
Forum: Advanced users
Topic: Pool Pump and PWM/GPIO speed control
Replies: 19
Views: 12935

Re: Pool Pump and PWM/GPIO speed control

The result of a square wave output to the audio interface : http://devrat.aquarat.za.net/assets/osc03.jpg http://devrat.aquarat.za.net/assets/osc04.jpg The core chunk of code that generated this (Java) : for (int i = 0; i < buf.length; i++) { if(i % 2 == 0) { buf[i] = (byte) 255; } else { buf[i] = (...
by aquarat
Tue Oct 02, 2012 3:18 pm
Forum: Advanced users
Topic: Pool Pump and PWM/GPIO speed control
Replies: 19
Views: 12935

Re: Pool Pump and PWM/GPIO speed control

I just found a programme I wrote 4 years ago that used the audio output as an Software Defined Radio (emulated DCF77 time signals)... gonna quickly hack it to do PWM.
by aquarat
Tue Oct 02, 2012 2:57 pm
Forum: Advanced users
Topic: Pool Pump and PWM/GPIO speed control
Replies: 19
Views: 12935

Re: Pool Pump and PWM/GPIO speed control

Here's a thought... PWM... on the audio output... ? 44.1kHz sample rate... :D :D :D
by aquarat
Tue Oct 02, 2012 11:04 am
Forum: Advanced users
Topic: Pool Pump and PWM/GPIO speed control
Replies: 19
Views: 12935

Re: Pool Pump and PWM/GPIO speed control

Hi Janek Thanks for the thought, but it would be damaging and highly inefficient to turn a pool pump (single phase, 240VAC induction motor) on and off for seconds at a time. However, you mentioned a magical word : "triac" And this has got me thinking; Triacs can turn loads on and off very quickly, t...
by aquarat
Sun Sep 30, 2012 1:29 pm
Forum: Advanced users
Topic: Pool Pump and PWM/GPIO speed control
Replies: 19
Views: 12935

Pool Pump and PWM/GPIO speed control

Hi I'm currently using a Raspberry Pi to control my pool pump (NTP means it'll always turn on at the right time... and it's easily programmable). I was wondering, would it be possible to use the Pi to control the speed of the pump ? The pump is a 750w, single phase device. It has a capacitor on it. ...
by aquarat
Tue Sep 11, 2012 4:10 pm
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 123282

Re: NTP PPS

Thanks Paul, there's no rush :) . @ peterwillcn : I have a Motorola Oncore UT+, but as yet I haven't been able to get this working with ntpd. I haven't tried very hard. The GPS I'm using uses NMEA over ttyAMA0 whereas the Motorola GPSs use the Motorola Binary protocol... NTPd does support this but I...
by aquarat
Mon Sep 10, 2012 10:43 pm
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 123282

Re: NTP PPS

Thanks bytecounter :)

I'm busy downloading the various tools/source to compile the kernel myself... but my objective is mdadm support :P .
by aquarat
Mon Sep 10, 2012 3:37 pm
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 123282

Re: NTP PPS

Hey Paul I'm currently using the custom kernel on the Raspbian distribution. I just connected an external GPS antenna to my Adafruit GPS receiver, so that might further improve the jitter (although I don't think ntpd can go below 0.002?) . If it makes a difference I run ntpd as root. The first time ...
by aquarat
Mon Sep 10, 2012 8:15 am
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 123282

Re: NTP PPS

Some hiccups, I don't know how to "elegantly" persistently link (ln) /dev/ttyAMA0 [target] to /dev/gps0 and ln /dev/pps0 to /dev/gpspps0.

At the moment I'm doing it with a cron job.
by aquarat
Mon Sep 10, 2012 7:34 am
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 123282

Re: NTP PPS

Pic : (hosted on a pi) http://41.134.20.29/gpsandpismall.jpg hey the gps module type ? plesae hardware wiring diagram, write a wizard, I also want to build a list in accordance with the practice as well as hardware. I don't really understand what you're saying peterwillcn ? But I'll probably make a...
by aquarat
Sat Sep 08, 2012 3:37 pm
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 123282

Re: NTP PPS

And a further update :
Image
You can clearly see a very large improvement between the x86/GPS-OXCO combination and the Pi/GPS-PPS solution.

The x86 system read the PPS using the DCD line on the RS232 port.

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