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by dentex
Mon Sep 19, 2016 12:26 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Debugging a I2C 20x4 LCD [SOLVED - hardware issue]
Replies: 27
Views: 5401

Re: Debugging a I2C 20x4 LCD

Thanks for the additional information. Unfortunately I didn't have time to check again this LCD...
Do you think there's anything on the LCD IC itself that is worth looking at? (To identify IC packages, etc...)

Thanks.
by dentex
Fri Sep 16, 2016 9:25 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Debugging a I2C 20x4 LCD [SOLVED - hardware issue]
Replies: 27
Views: 5401

Re: Debugging a I2C 20x4 LCD

My example at http://abyz.co.uk/rpi/pigpio/examples.html#Python_i2c_lcd_py defaults to address 0x27 so may be compatible with your backpack. Thanks Joan, I'll try your library tomorrow and I'll let you know how it goes. W.r.t. a blank display - did you also try tweaking the contrast pot on the back...
by dentex
Fri Sep 16, 2016 5:46 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Debugging a I2C 20x4 LCD [SOLVED - hardware issue]
Replies: 27
Views: 5401

Debugging a I2C 20x4 LCD [SOLVED - hardware issue]

Hello! I have this 20x4 LCD. I know they are not all the same: in fact many libraries I tried had the address 0x03 or 0x3f, but my LCD returns: $ i2cdetect -y 1 0 1 2 3 4 5 6 7 8 9 a b c d e f 00: -- -- -- -- -- -- -- -- -- -- -- -- -- 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 20: -- -- --...
by dentex
Mon Sep 12, 2016 12:29 pm
Forum: Graphics, sound and multimedia
Topic: Bluetooth audio streaming
Replies: 131
Views: 348946

Re: Bluetooth audio streaming

Is there anything in /var/log/syslog regarding PulseAudio? My BT is really jittery and the syslog is full of messages saying PulseAudio has skipped playback Right... syslog... Never looked at it. The fact is also that attempting to obtain the connection between the smartphone and the RPi it's a rea...
by dentex
Mon Sep 12, 2016 10:35 am
Forum: Graphics, sound and multimedia
Topic: Bluetooth audio streaming
Replies: 131
Views: 348946

Re: Bluetooth audio streaming

Well, I'm quite stubborn; I want this stuff fixed. :evil: (incidentally, "pactl load-module module-bluetooth-discover" doesn't work probably because the module is already loaded). I have the android phone connected and the RPi is recognized as an audio bluetooth device. It seems that I have the thin...
by dentex
Sun Sep 11, 2016 6:09 pm
Forum: Graphics, sound and multimedia
Topic: Bluetooth audio streaming
Replies: 131
Views: 348946

Re: Bluetooth audio streaming

I always load modules by adding the following lines to /etc/pulse/system.pa or default.pa, depending on whether you're running PA in system-wide mode or not. Both places won't hurt. load-module module-bluetooth-discover load-module module-bluetooth-policy I'm not sure what you mean about bluetoothc...
by dentex
Sun Sep 11, 2016 4:51 pm
Forum: Graphics, sound and multimedia
Topic: Bluetooth audio streaming
Replies: 131
Views: 348946

Re: Bluetooth audio streaming

I tried to figure out this stuff for the whole day... and now I'm kinda frustrated... I'm at the point that I have the android phone paired and connected, so the bluetooth part should be OK... But with pulseaudio, that's another story. It seems I really can't do the part: pactl load-module module-bl...
by dentex
Sun Sep 11, 2016 7:27 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Does i2c need pullups (resistors, not diapers!)
Replies: 25
Views: 12467

Re: Does i2c need pullups (resistors, not diapers!)

most of the issues occur when the I2C device expects a logic high that is higher than 3.3V. For example many 5V logic devices expect a minimum high level of 70% of their VCC, that is for a 5V powered device 5.0 * 0.7 = 3.5V. Does that mean that no harm will come to the RPi if I hook up an I2C devic...
by dentex
Sat Sep 10, 2016 8:52 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: I2C and 5V - Definitive answer?
Replies: 28
Views: 7638

Re: I2C and 5V - Definitive answer?

... It's zero. :shock: When measured between Pi ground and backpack SDA/SCL when powered from Pi ground and Pi 5V? That's fortunate. Apparently it's not like many of the backpacks which have their own pull-ups to VCC. That should be fine to use on the Pi. Indeed... (the noob of me, sorry): it's 4V ...
by dentex
Sat Sep 10, 2016 8:34 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: I2C and 5V - Definitive answer?
Replies: 28
Views: 7638

Re: I2C and 5V - Definitive answer?

joan wrote:Power the backpack from a Pi 5V and ground pin.

Then measure the voltage on the backpack's SDA and SCL pins.

If it's 5V then nobody is going to assure you it is safe.
It's zero. :shock:
by dentex
Fri Sep 09, 2016 8:20 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: I2C and 5V - Definitive answer?
Replies: 28
Views: 7638

Re: I2C and 5V - Definitive answer?

joan wrote:Power the backpack from a Pi 5V and ground pin.

Then measure the voltage on the backpack's SDA and SCL pins.

If it's 5V then nobody is going to assure you it is safe.
Thanks for this "practical" answer. Will be the 1st thing I'll do tomorrow when I'll go back home.
by dentex
Fri Sep 09, 2016 8:11 pm
Forum: Automation, sensing and robotics
Topic: DS18B20 5V external power with 3V3 dataline
Replies: 9
Views: 5345

Re: DS18B20 5V external power with 3V3 dataline

No problema! Good luck, please keep us posted.. Thanks mate! Much appreciated. At this point, sorry if I dare ask... but I was trying to understand once and for all the relationship between 3v3 and 5v on the RPi... and I came to the problem of having, i.e., an I2C-LCD screen powered with 5V and an ...
by dentex
Fri Sep 09, 2016 7:58 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: I2C and 5V - Definitive answer?
Replies: 28
Views: 7638

Re: I2C and 5V - Definitive answer?

Hello! I'm reviving this post because I was searching for a "Definitive answer" on this matter, too. I'm sorry to say that probably the thread in the end went more on the "good circuit design" topic; as a result, it's not perfectly clear to me if it's safe or not to use a I2C device, with the RPi, a...
by dentex
Fri Sep 09, 2016 6:49 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Advice on GPIO configuration
Replies: 2
Views: 756

Re: Advice on GPIO configuration

... Yes. The valve have "end-stops" so leaving the switch in one position, won't make the valve to draw current, once it set up for position. [...] I think I don't need to mention, that you have to use some circuit wit transistors to drive relays from GPIOs (I assume that by looking at your post co...
by dentex
Fri Sep 09, 2016 5:54 pm
Forum: Automation, sensing and robotics
Topic: DS18B20 5V external power with 3V3 dataline
Replies: 9
Views: 5345

Re: DS18B20 5V external power with 3V3 dataline

Hi, I used to have my DS18B20 operating with my RasPi continuously about a year and half gathering the ambient temp in the room while was installed my RasPi, with any glitches. My line between the RasPi ant the temp sensor was about 30 ~ 40 cms, twisted wire, BTW be sure to use good quality twisted...
by dentex
Thu Jul 21, 2016 6:15 pm
Forum: Troubleshooting
Topic: nfs-kernel-server not starting anymore since few days/weeks
Replies: 15
Views: 9347

Re: nfs-kernel-server not starting anymore since few days/we

moreins wrote: nfs-re-restart
Thanks for this solution! Works OK for me :)

A question: is the initial "sleep 45" necessary?
by dentex
Thu Jul 14, 2016 5:25 pm
Forum: Italiano
Topic: Cerco RaspberryPi modello B+
Replies: 0
Views: 353

Cerco RaspberryPi modello B+

Ciao a tutti.
[chiedo scusa ai mod se questa non è la sezione giusta - spostate o cancellate pure]

Come da titolo, cerco il B+ ...

Se qualcuno che è passato al modello 2 o 3, vuole vendersi il suddetto modello, eccomi. ;)
Pagamento solo con PayPal.

Grazie.
by dentex
Tue Jul 12, 2016 4:50 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Small circuit review: 2N2222A as a switch
Replies: 6
Views: 2113

Re: Small circuit review: 2N2222A as a switch

Cool... thanks again.

And the label on the fans says "brushless. :)
by dentex
Tue Jul 12, 2016 4:29 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Small circuit review: 2N2222A as a switch
Replies: 6
Views: 2113

Re: Small circuit review: 2N2222A as a switch

Burngate wrote:...

The TIP122 is a Darlington - two transistors in series - so it's got a far higher gain.
Far better for the job!
Thanks Burngate for the answer!

What do you think about the diode? Is it necessary? And how I know what to use?
by dentex
Tue Jul 12, 2016 3:44 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Small circuit review: 2N2222A as a switch
Replies: 6
Views: 2113

Re: Small circuit review: 2N2222A as a switch

well, I suppose the answer is NO.
With one fan is OK, but with two of them the transistor became really hot in a few seconds, so I disconnected it.
Trying now with a TIP122 and it's barely warm.
by dentex
Tue Jul 12, 2016 3:35 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: TIP122 and LED strip, ON/OFF is OK, not PWM [SOLVED/WORKS]
Replies: 5
Views: 2124

Re: TIP122 and LED strip, ON/OFF is OK, not PWM [SOLVED/WORK

Hello! ...me again.
Quick question: considering a load of 30 LEDs of the 5630 smd type (1 meter long strip, 10 module with 3 LEDs each), would the above circuit work with just a 2N2222A transistor?
by dentex
Tue Jul 12, 2016 3:24 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Small circuit review: 2N2222A as a switch
Replies: 6
Views: 2113

Small circuit review: 2N2222A as a switch

Hello! I would love if someone may want to take a look at what I thought to do to switch ON and OFF a couple of PC fans with a GPIO pin. I actually tried and it works; but, is it safe? Do I need something else (a diode)? 2N2222A_as_fan_switch.jpg The fans run at 12V and 150mA. For a LED strip I used...
by dentex
Sat Jul 09, 2016 3:31 pm
Forum: Troubleshooting
Topic: DS18B20 reading high
Replies: 9
Views: 1555

Re: DS18B20 reading high

Ok thanks.
by dentex
Sat Jul 09, 2016 3:15 pm
Forum: Troubleshooting
Topic: DS18B20 reading high
Replies: 9
Views: 1555

Re: DS18B20 reading high

Ok. So it's not a DS18B20 probe, right?

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