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by azerty
Thu Mar 05, 2015 10:17 pm
Forum: General discussion
Topic: Hiss coming from Pi2
Replies: 25
Views: 4681

Re: Hiss coming from Pi2

It could be piezoelectric effect affecting the ceramic input capacitors of the Pi's onboard switching power supplies. Audible noise means the wallwart has a low switching frequency (kilohertz range), which means it would also have relatively large voltage ripple, which is doubly bad in terms of audi...
by azerty
Wed Jun 26, 2013 8:45 pm
Forum: General discussion
Topic: I2C LCD not detected
Replies: 30
Views: 17222

Re: I2C LCD not detected

It could be a logic threshold issue. I2C to LCD typically uses a PCF8574 or similar. With VCC = 5V, logic high is 0.7*VCC = 3.5V which is higher than the Pi's 3.3V I2C bus. You can try powering VCC from 3.3V, if i2cdetect picks up the I2C LCD then that's likely the problem. Unfortunately, many LCDs ...
by azerty
Sat Aug 11, 2012 1:49 am
Forum: General discussion
Topic: Monitoring battery levels
Replies: 7
Views: 5523

Re: Monitoring battery levels

If you end up going with a Li or LiPO battery this could be what you're looking for:
https://www.sparkfun.com/products/10617
by azerty
Thu Jul 26, 2012 6:04 am
Forum: General discussion
Topic: Switching regulators for Raspberry Pi
Replies: 39
Views: 26026

Re: Switching regulators for Raspberry Pi

http://i.imgur.com/J2XVx.jpg Hmm...not great, but I think you can get a better idea of what the module looks like. ...and what ones did you buy [link for the lazy] I should have made it more clear, but there are no switching regulators in the same package as the linear regulators available on the m...
by azerty
Wed Jul 25, 2012 8:33 am
Forum: General discussion
Topic: Switching regulators for Raspberry Pi
Replies: 39
Views: 26026

Switching regulators for Raspberry Pi

There's been some discussion on the topic of replacing the Raspberry Pi's linear regulators with higher efficiency switching regulators. godFather89 has a nifty solution for his Lapdock project, but I wanted to try making more of a drop-in replacement. http://i.imgur.com/dQAkY.jpg As you can see, RG...
by azerty
Wed Jul 11, 2012 3:42 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Nexus 7 DSI
Replies: 6
Views: 10769

Re: Nexus 7 DSI

The panel in the Nexus 7 uses a LVDS interface. There's a TI SN75LVDS83B parallel to LVDS transmitter in step 17 of the ifixit teardown.
by azerty
Wed Jul 11, 2012 3:27 am
Forum: General discussion
Topic: RasPi power usage measurements ALL Models
Replies: 156
Views: 278489

Re: RasPi power usage measurements ~2 watts at idle

Looks like the LAN chip is still drawing quite a bit of current. Thanks for this. I believe the LAN chip is held in reset which I would expect to minimise power. Any suggestions? In the LAN9512 datasheet it says that the default USB suspend state reduces current down to 4.2 mA typical, so my first ...
by azerty
Tue Jul 10, 2012 2:45 am
Forum: General discussion
Topic: RasPi power usage measurements ALL Models
Replies: 156
Views: 278489

Re: RasPi power usage measurements ~2 watts at idle

With the new firmware I measured 0.107 A after shutdown -h now.
Then I waited 15 for the temperature to re-equilibriate and took this picture:
Image
Looks like the LAN chip is still drawing quite a bit of current.
by azerty
Sat Jul 07, 2012 6:46 pm
Forum: HATs and other add-ons
Topic: SD card sticking out ? Use RSMMC
Replies: 56
Views: 30199

Re: SD card sticking out ? Use RSMMC

That does indeed look VERY interesting! Is it a proprietary device, or a purpose made 'one off'... or just a clever bit of 'Photoshopping'? ;) Please tell us more! I made this to go with an add-on board I'm making that has IO connectors hanging off the edge, which prevent the use of a full sized SD...
by azerty
Sat Jul 07, 2012 3:22 am
Forum: HATs and other add-ons
Topic: SD card sticking out ? Use RSMMC
Replies: 56
Views: 30199

Re: SD card sticking out ? Use RSMMC

Dilligaf wrote:Someone needs to manufacture and sell a "MicroSD Pidaper", basically a half height micro sd adapter, then a micro sd would sit flush.
Something like this, maybe?
Image

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