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by Metz
Mon Sep 09, 2013 4:51 pm
Forum: Media centres
Topic: XBMC -> MySql with database on NAS drive
Replies: 3
Views: 4933

Re: XBMC -> MySql with database on NAS drive

Thanks for that....atleast it means I'm not wasting my time :)
by Metz
Mon Sep 09, 2013 11:20 am
Forum: Media centres
Topic: XBMC -> MySql with database on NAS drive
Replies: 3
Views: 4933

XBMC -> MySql with database on NAS drive

Hi, I run 3 PIs at home (amongst many others) that operate as XBMC media players. I would like to move to a centralised library using MySQL. The plan is to have another Raspi operating as the MySQL server, permanently on. The key is that I would like the Pi to host the server software, but with the ...
by Metz
Tue May 28, 2013 11:28 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Cheap I/O Expansion chips
Replies: 16
Views: 10562

Re: Cheap Expansion chips

Shift registers allow you to send through an 8-bit pattern into the chip, and then 'latch' that pattern over to the output pins. So, sending through 0xAA would give you b10101010, meaning pins 2,4,6 and 8 would be high (Vcc), with the others being low (GND).
by Metz
Tue May 28, 2013 11:22 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Cheap I/O Expansion chips
Replies: 16
Views: 10562

Re: Cheap Expansion chips

I've quite succesfully used a set of 15 74HC595s from 3 wires on the Raspi. All daisy chained together, those 15 chips control 240 LEDs. These are only good for output, though, not input. They draw very little current, and I can run those 240 LEDs off a 5v 1A charger, including running the Pi. If yo...
by Metz
Tue May 28, 2013 9:56 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Raspi +ATMega328 + I2C - problem with serial monitor
Replies: 0
Views: 548

Raspi +ATMega328 + I2C - problem with serial monitor

I'm trying to control an ATMega328 from my Pi. I using the WiringPi library in 'C', and the Wire library on the Arduino. I have setup a level-shifter using a couple of 2n7000s on the SDA & SCL lines, which appears to work fine. The ATMega is connected to a USB serial programmer, which also works fin...
by Metz
Tue Feb 26, 2013 10:39 am
Forum: Automation, sensing and robotics
Topic: Circuit Design Software
Replies: 9
Views: 4130

Re: Circuit Design Software

Am I right in saying that the OP never stipulated that this had to run on the Pi? Another vote here for KiCad. I've been using it for a while, and although the interface is quite archaic, it does the job. There is no testing in the 'simulation' front, but it will perform limited validation...ensurin...
by Metz
Sat Feb 09, 2013 11:15 am
Forum: Automation, sensing and robotics
Topic: Single power supply for both 12v and 5v
Replies: 11
Views: 26230

Re: Single power supply for both 12v and 5v

And here it is...all seem fairly stable. http://instagram.com/p/VggB1IOxNw/ So, 12v 1500ma wall wart from Maplin (£18, I think). Supply splits into the 4.3" monitor from Ebay (£19), and the 12v-5v converter found inside a car charger included in the Sony PSP charger kit from the poundshop...for...yo...
by Metz
Sat Feb 09, 2013 10:13 am
Forum: Automation, sensing and robotics
Topic: Single power supply for both 12v and 5v
Replies: 11
Views: 26230

Re: Single power supply for both 12v and 5v

So....minor yet interesting development. Another visit to the poundshop yesterday. These places really are a treasure trove of goodness for cheap Pi accesories ;) Latest find is... "Competition Pro - Charge Pack - car adapter and ac power adaptor for Sony PSP" I've never found genuine 5v USB wall wa...
by Metz
Fri Feb 08, 2013 2:49 pm
Forum: Automation, sensing and robotics
Topic: Single power supply for both 12v and 5v
Replies: 11
Views: 26230

Re: Single power supply for both 12v and 5v

Thanks aframe, thats the perfect solution, right there :)
by Metz
Fri Feb 08, 2013 12:51 pm
Forum: Automation, sensing and robotics
Topic: Single power supply for both 12v and 5v
Replies: 11
Views: 26230

Re: Single power supply for both 12v and 5v

Thanks guys...much appreciated. I was aware that I could buy a UBEC to do the job, but the point is to make this myself, and make it from cheap, readily available components. In this case, size does indeed matter, as does weight. I have a handfull of voltage regulators (both 7805 and 317s) so I figu...
by Metz
Fri Feb 08, 2013 12:25 pm
Forum: Automation, sensing and robotics
Topic: Single power supply for both 12v and 5v
Replies: 11
Views: 26230

Single power supply for both 12v and 5v

I have a requirement for a project of mine that involves powering the Raspberry Pi and a screen, and potentially, a 4-port USB hub. Obviously, the Pi and the Hub want a 5v input, but the screen needs 12v. Is there a way I can use a single wall-wart supply to provide the source for all the devices? I...
by Metz
Mon Jan 07, 2013 11:29 am
Forum: Automation, sensing and robotics
Topic: Battery power
Replies: 20
Views: 11348

Re: Battery power

I've discovered that the poundshop is your friend in this instance :) I'm sure someone will tell me its a bad idea, but I bought an 'emergency phone charger' for the princely sum of £1....put four AAA batteries in it (20 for....you guessed it....£1). It has a micro-USB connector on it...and I just p...
by Metz
Mon Jan 07, 2013 11:19 am
Forum: Automation, sensing and robotics
Topic: Hardware recycling - Power Supplies
Replies: 3
Views: 965

Re: Hardware recycling - Power Supplies

Doh...fuse, of course :)

Yup, there's a fuse on the board (infact...on both of the boards that I recovered). Should be a simple matter of checking the rating on that :D

<palmface>

Thanks!!
by Metz
Mon Jan 07, 2013 10:20 am
Forum: Automation, sensing and robotics
Topic: Hardware recycling - Power Supplies
Replies: 3
Views: 965

Hardware recycling - Power Supplies

I an effort to tidy up after myself...and declutter, I decided last week to by some plastic containters and start organising and sorting out a lot of the useless junk I've kept over the years. Whilst on a trip to the loft, I came across some old hardware....an old dvd player, and two old set-top box...
by Metz
Sun Dec 30, 2012 10:21 am
Forum: Networking and servers
Topic: What can I do with a bramble?
Replies: 3
Views: 2569

Re: What can I do with a bramble?

Distributed rendering? Aka....a render farm for something like Blender. This is something I'm going to attempt soon-ish :)
by Metz
Tue Oct 16, 2012 1:06 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: GPIO performance
Replies: 7
Views: 2756

Re: GPIO performance

Thanks Mike, much appreciated :) The reason for the only have a single LED lit per cell in a single pass is purely to control power demand. So...if I were top change that to 2 LEDs, for example, is that simply adding up the Max Continuous Foward Current specified for the LEDs? The link is very usefu...
by Metz
Tue Oct 16, 2012 9:47 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: GPIO performance
Replies: 7
Views: 2756

GPIO performance

Looking for ways to improve the performance of my code. I'm working on a project that controls a large matrix of LEDs through a series of shift-registers (74HC595s). I initially started with python, but that was nowhere near fast enough. I switched to C, using the bcm2835 library by Mike McCauley, w...
by Metz
Thu Jul 12, 2012 10:55 am
Forum: Troubleshooting
Topic: Single GPIO pin failure
Replies: 8
Views: 1404

Re: Single GPIO pin failure

Thanks for your help everyone. +1 Karma all round. I'll try your suggestions, but it's looking more and more like I've damaged something. Hey ho :)
by Metz
Thu Jul 12, 2012 8:11 am
Forum: Troubleshooting
Topic: Single GPIO pin failure
Replies: 8
Views: 1404

Re: Single GPIO pin failure

Addendum:- There are 1k resistors between each GPIO pin and the base of the NPNs.
by Metz
Thu Jul 12, 2012 8:09 am
Forum: Troubleshooting
Topic: Single GPIO pin failure
Replies: 8
Views: 1404

Re: Single GPIO pin failure

Sorry, you're quite right, I was a little light on information.... so :- All pins are output only, connected to breadboard, and driving a 74HC595 shift register. The pins are isolated from a 5v 700mA power source through individual NPN transistors. I'm only using pins 1-4 (7,11,13,15) and GND. The s...
by Metz
Wed Jul 11, 2012 9:32 pm
Forum: Troubleshooting
Topic: Single GPIO pin failure
Replies: 8
Views: 1404

Single GPIO pin failure

I appear to have a single pin failing on my Pi. Gpio 22 (pin 15) is simply not working. Is there anything I can do ? It was working just fine, but appears to have simply stopped, mid stream.

Any ideas?
by Metz
Tue Jul 03, 2012 5:22 pm
Forum: HATs and other add-ons
Topic: Isolating GPIOs and using alternate power source
Replies: 20
Views: 13161

Re: Isolating GPIOs and using alternate power source

Thanks guys. Karma+1 :)
by Metz
Tue Jul 03, 2012 4:14 pm
Forum: HATs and other add-ons
Topic: Isolating GPIOs and using alternate power source
Replies: 20
Views: 13161

Re: Isolating GPIOs and using alternate power source

Thanks exartemarte. How about if I want to do it myself, for just one gpio pin? Two transistor....and make up my own Darlington pair? The bit I don't understand is where the ground goes? Doesn't the ground need to be common? If so, do I just connect the GND pin on my Pi to the ground of the alternat...
by Metz
Tue Jul 03, 2012 9:43 am
Forum: HATs and other add-ons
Topic: Isolating GPIOs and using alternate power source
Replies: 20
Views: 13161

Isolating GPIOs and using alternate power source

I've no idea if this is the right forum, but I can't find another hardware related one. I'll move the post if needed. What I am attempting to do is use the GPIO pins to act as the signal on the base of a transistor, but have a seperate source for the power runing through collector->emitter and onto ...
by Metz
Thu Jan 12, 2012 4:27 pm
Forum: General discussion
Topic: The official "Are they nearly here yet?" thread.
Replies: 33
Views: 6705

Re: The official "Are they nearly here yet?" thread.

so.....

Are they nearly here yet?!

Seriously...I've got ideas coming out of me like sweat...at this rate, I'll drown before I get one

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