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by shortcircuit
Wed Oct 24, 2012 4:48 pm
Forum: General discussion
Topic: Big open news!
Replies: 58
Views: 9059

Re: Big open news!

That is indeed a big step in the right direction, thank you !
by shortcircuit
Fri Oct 19, 2012 4:03 pm
Forum: General discussion
Topic: Raspberry Pi with 512mb RAM in the Wild and Element14...
Replies: 213
Views: 50368

Re: Raspberry Pi with 512mb RAM in the Wild and Element14...

Dweeber wrote:Did you do this yet?

sudo apt-get upgrade
sudo apt-get update
Those should be done in the opposite order:
sudo apt-get update
sudo apt-get upgrade
The first updates the local copy of the list of available packages and the second does the actual fetching and installing.
by shortcircuit
Fri Sep 28, 2012 6:55 pm
Forum: HATs and other add-ons
Topic: Is 3V3 GPIO HIGH voltage enough to fully turn on ULN2803a?
Replies: 7
Views: 4484

Re: Is 3V3 GPIO HIGH voltage enough to fully turn on ULN2803

You are advised to choose the darlingtons load resistance so that the 500mA absolute maximum limit is not exceeded. A late reply but hopefully not too late: You should never ever go near the absolute maximum ratings for any component ! Doing it is begging for trouble :) Read the fine print slightly...
by shortcircuit
Mon Sep 17, 2012 5:14 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Injecting 12v on to the GPIO 5 volt pin to power RPi - don't
Replies: 16
Views: 3336

Re: Injecting 5v on to the GPIO 5 volt pin to power RPi - do

Mind you, it is possible that something else is blown (I think the SOC, while primarily operating from 3.3V, does have some 5V feeds also), but maybe worth risking a 60p spare part to find out? Ah yes, apparently it does. I'm a bit surprised since it shouldn't really need 5V for anything. That mean...
by shortcircuit
Sun Sep 16, 2012 11:45 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Injecting 12v on to the GPIO 5 volt pin to power RPi - don't
Replies: 16
Views: 3336

Re: Injecting 5v on to the GPIO 5 volt pin to power RPi - do

So you probably killed RG2, but the other parts may still be intact. A good candidate for conversion to using a switched regulator if all the other parts look ok. :)
by shortcircuit
Mon Sep 03, 2012 5:29 pm
Forum: Troubleshooting
Topic: using vnc to connect to a Linux computer?
Replies: 1
Views: 887

Re: using vnc to connect to a Linux computer?

If you haven't done it already you first need to start the server on the pi. The first time you do it you'll have to pick a password for the vnc connection: pi@raspberrypi ~ $ vncserver -geometry 1024x768 You will require a password to access your desktops. Password: Verify: Would you like to enter ...
by shortcircuit
Sat Sep 01, 2012 11:52 am
Forum: General discussion
Topic: Switching regulators for Raspberry Pi
Replies: 39
Views: 26220

Re: Switching regulators for Raspberry Pi

Do you any better data on this chip as the pdf files found seems very small and limit in details. Unfortunately I don't have any better specs. I did a little load testing of a VMP3111 configured to put out 1.86 V today. The sweet spot seems to be somewhere near 700 mA which is more than we'll see o...
by shortcircuit
Fri Aug 31, 2012 10:15 pm
Forum: General discussion
Topic: Switching regulators for Raspberry Pi
Replies: 39
Views: 26220

Re: Switching regulators for Raspberry Pi

The 5v line Bench PSU -> Fluke 8846A(mA mode) -> RPI board GPIO pin The 3.3 line Bench PSU -> switchmodeboard -> 1 ohm shunt-> RPI board GPIO pin (The 1 ohm shunt is used with the Fluke scopemeter in mA mode) The 1.8 line Bench PSU -> switchmodeboard -> Fluke 287(in mA mode) -> RPI board GPIO pin T...
by shortcircuit
Fri Aug 31, 2012 8:51 pm
Forum: General discussion
Topic: Switching regulators for Raspberry Pi
Replies: 39
Views: 26220

Re: Switching regulators for Raspberry Pi

it can be that i have an error but i have tryed to do the best i can to verify and make sure the values are correct. you can see all the test details in the blog so if you can spot where the error is then i can try recheck things. Where did you have the current meters connected in test 5 and 6 ? Th...
by shortcircuit
Fri Aug 31, 2012 8:20 pm
Forum: General discussion
Topic: Switching regulators for Raspberry Pi
Replies: 39
Views: 26220

Re: Switching regulators for Raspberry Pi

Here is my blog post about it http://www.tooms.dk/Tblog/Showblog1.asp?BlogID=201208292042561198 Hmm... the results look very strange. The total current in test 5 should have been close to the current in test 3 but your result in test 5 is over 200 mA lower. That has to be either due to a faulty RG2...
by shortcircuit
Fri Aug 31, 2012 5:55 pm
Forum: General discussion
Topic: Switching regulators for Raspberry Pi
Replies: 39
Views: 26220

Re: Switching regulators for Raspberry Pi

Hi Do you any better data on this chip as the pdf files found seems very small and limit in details. I think you will be able to get the power lower then this by finding an good converter there is having the 95% eff. at the right point. I have tryed to test how much the RPI is using without the RG1...
by shortcircuit
Fri Aug 31, 2012 5:18 pm
Forum: General discussion
Topic: Switching regulators for Raspberry Pi
Replies: 39
Views: 26220

Re: Switching regulators for Raspberry Pi

I opted for DC-DC converter modules with the inductors built in. The VMP3111 seems to work well for this purpose. It is a bit overkill (rated to 2 amps) but easy to solder since the package uses the same 2.54 mm pitch as through-hole mount components even though it is a surface-mount part. I first r...
by shortcircuit
Thu Aug 16, 2012 7:17 pm
Forum: General programming discussion
Topic: Lightweight continuous integration on the PI
Replies: 1
Views: 3478

Lightweight continuous integration on the PI

Buildbot is available a package for Raspbian but it might be a bit heavy for some use cases (even though it is much lighter than java-based systems like Jenkins). I decided to try installing SCIT http://code.google.com/p/scit/ on my PI. To my surprise it worked without any tweaking if you follow the...
by shortcircuit
Sat Aug 04, 2012 5:33 pm
Forum: Automation, sensing and robotics
Topic: wireless solar nature/security camera
Replies: 9
Views: 6595

Re: wireless solar nature/security camera

Nice project but if you want it to run 24/7 you need way more solar power, even in the summer. The panels produce much less on a cloudy day. A 50W panel might be enough in a good location in summer, for winter time operation I'd go with something even bigger. Luckily the panel prices have come down ...

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