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by pksato
Sat Dec 05, 2015 12:34 pm
Forum: General discussion
Topic: RPi GPIO from 3v3 to 5v
Replies: 9
Views: 1577

Re: RPi GPIO from 3v3 to 5v

You need a driver.
Drivers are electronic circuit that control high power loads.
RPi, and others, have a logic level power output, just enough to activate others similar chips.
Have a lots way to make a driver, a simple mosfet transistor, resistor and bipolar transistor, dedicate chips.
by pksato
Sat Dec 05, 2015 12:06 pm
Forum: General discussion
Topic: RPi GPIO from 3v3 to 5v
Replies: 9
Views: 1577

Re: RPi GPIO from 3v3 to 5v

Hi,
for what application?
Most logic chip accept 3v3 as valid HIGH input level. Except CMOS, 40xx séries.
If need only one direction, TTL chips like 74HC245, 74HC374, etc can be used (and are cheap chips).
And other ways to shift 3v3 to 5V.
by pksato
Thu Dec 03, 2015 5:32 pm
Forum: General discussion
Topic: Controlling Microphone Audio
Replies: 2
Views: 605

Re: Controlling Microphone Audio

Hi,
The sound source is a microphone or a high level source like radio, mp3, etc?
Some microphone have a pre amplifier.

In case of high level source, need to use a impedance match network (attenuator), a potentiometer.
by pksato
Wed Nov 25, 2015 7:10 pm
Forum: Português
Topic: wifi
Replies: 3
Views: 809

Re: wifi

Parece ser problema com a fonte de alimentação, que não tem potência suficiente para alimentar o RPi e o adaptador wifi.
Se for modelo B+ (versão 1 ou 2) o led power deve piscar em casos de problemas de alimentação.
Ligue já com o adaptador conectado.
by pksato
Wed Nov 25, 2015 7:06 pm
Forum: Português
Topic: Raspberry PI (modelo B) Tem como acender LED com ele ?
Replies: 1
Views: 593

Re: Raspberry PI (modelo B) Tem como acender LED com ele ?

Ola, não compreendi a sua pergunta. A luz de LED se refere a um dos leds existente na placa, ou um led conectando em um dos pinos de GPIO? Acredito que houve uma mudança no endereço dos leds no modelo 2. Teria que adaptar o programa. Se o led esta nos pinos de GPIO, e corretamente conectado usando u...
by pksato
Mon Nov 23, 2015 1:22 pm
Forum: Raspberry Pi OS
Topic: about omx player
Replies: 17
Views: 8396

Re: about omx player

Thank u for your supports. but i need to play the videos automatically without giving commands in LXTerminal Open file manager, go to video folder, and try to open. If open fails or open with wrong application, put mouse cursor above file icon, right click, select open with, select omxplayer from l...
by pksato
Mon Nov 23, 2015 11:45 am
Forum: Raspberry Pi OS
Topic: about omx player
Replies: 17
Views: 8396

Re: about omx player

Thank u for your supports. but i need to play the videos automatically without giving commands in LXTerminal Open file manager, go to video folder, and try to open. If open fails or open with wrong application, put mouse cursor above file icon, right click, select open with, select omxplayer from l...
by pksato
Tue Nov 17, 2015 1:58 pm
Forum: General discussion
Topic: MP3 files
Replies: 19
Views: 3253

Re: MP3 files

You can split long audio file on small ones detecting silence.

Code: Select all

sox -V3 input.wav output.wav silence 1 3.0 0.1% 1 0.3 0.1% : newfile : restart
by pksato
Sat Nov 14, 2015 2:24 am
Forum: General discussion
Topic: Car speackers
Replies: 17
Views: 2137

Re: Car speackers

Hi, I want to use the raspberry to beautify my car. I thought to use the RSP for music and me is a doubt arose. It is possible to connect the car speakers to the micro-computer? I need some adapter or do you think it is impossible? Thank you Most car have a some type of audio system, a AM/FM rádio,...
by pksato
Thu Nov 12, 2015 1:17 pm
Forum: General discussion
Topic: Level Shifer
Replies: 29
Views: 5534

Re: Level Shifer

Hi, After read some text, and watch videos about voltage level shifter, and many of these text or video recommend to avoid voltage divider for high frequency, I decide to simulate some circuits to check that happens. We need some information before start design a level shifter, as operation frequenc...
by pksato
Wed Nov 11, 2015 6:58 pm
Forum: General discussion
Topic: Level Shifer
Replies: 29
Views: 5534

Re: Level Shifer

Two links about level shifters http://www.edn.com/design/analog/4318916/Don-t-pay-for-level-translators-in-systems-using-multiple-power-supply-voltages http://www.newark.com/pdfs/techarticles/microchip/3_3vto5vAnalogTipsnTricksBrchr.pdf And a video, does not take into account parasitic reactance, li...
by pksato
Mon Nov 09, 2015 8:03 pm
Forum: Português
Topic: Receptor ISDB-T
Replies: 40
Views: 28663

Re: Receptor ISDB-T

Ola, Estou pensando em tranformar um dos meus RPi (o de 256MB) em um receptor de TV Digital. Só que, precisária adquirir mais um receptor USB FullSeg. Mas, com essa alta do dolar e ser um pouco dificil achar um FullSeg nos sites chineses, acho que voi ter que dar um jeito de compartilhar o único ada...
by pksato
Mon Nov 09, 2015 5:26 pm
Forum: General discussion
Topic: Level Shifer
Replies: 29
Views: 5534

Re: Level Shifer

Voltage divider is safe, if proper connected.
Or replace R2 (GND side) for a zener diode.
Minimum voltage to RPi recognize as high is near 2V. Device to RPi not need level shifter.
If is official jtag, probable have a protection to avoid danger voltages.
by pksato
Mon Nov 09, 2015 4:57 pm
Forum: General discussion
Topic: Level Shifer
Replies: 29
Views: 5534

Re: Level Shifer

Voltage divider can work on GHz band. Just choose a low reactance packaging (SMT). Common carbon film resistor can be used above 5MHz. Just test, it cost only few cents (or free). Use high current (8mA) to maintain low RC constant. R1=82 R2=330 Oscilloscope Probe is a voltage divider, and work on hu...
by pksato
Sat Oct 24, 2015 10:42 am
Forum: General discussion
Topic: Does pulse length matter? (433mhz)
Replies: 2
Views: 1103

Re: Does pulse length matter? (433mhz)

Hi,
Not clear post.

It is a RF remote to control lights and other electric devices?
Work without connected to RPi?
Put, receiver far from other electric devices, like a PSU, and lamp ballasts.

Watch this video (only instructive information).
https://www.youtube.com/watch?v=XzwEymOslFo
by pksato
Sat Oct 24, 2015 10:23 am
Forum: Português
Topic: Problema com HUB HB-T68
Replies: 2
Views: 682

Re: Problema com HUB HB-T68

Se também não funciona no notebook, esse HUB deve estar com defeito.
Supondo que tenha feito as conexões corretamente, ou seja, ligado a fonte, e o cabo de interligação entre o RPi ou Notebook a o HUB, esse cabo vai conectado no soquete quadrado (não nos retangulares).
by pksato
Fri Oct 23, 2015 12:34 pm
Forum: General discussion
Topic: Please help. Electronics Advise Needed
Replies: 7
Views: 1266

Re: Please help. Electronics Advise Needed

Hi, As Doug sayed said, you can use optocoupler. Optocoupler or opto-isolator is device that use light to isolate two circuits. That consist of one led and a photo transistor, separate one from another with a gap. Common types are: PC817 Found on Switch Mode Power Supply. (4 pins) 4N25, 4N27 (6 pins...
by pksato
Wed Sep 09, 2015 7:59 pm
Forum: Beginners
Topic: Raspberry Pi 2 run a script
Replies: 6
Views: 973

Re: Raspberry Pi 2 run a script

HI,
If not need terminal interaction:
end script call command with &
myscript &
or
if need some dummy tty, use nohup tool.
nohup script &
nohup generate a nohup.log on current directory.
man nohup to more details.

& put command on background.
by pksato
Tue Sep 01, 2015 1:17 am
Forum: General discussion
Topic: Checking battery usage of a power bank.
Replies: 14
Views: 10422

Re: Checking battery usage of a power bank.

pksato, Almost certainly the battery bank discussed here has a built in voltage regulator and a USB socket. Oh, I miss (some translation confusion) a very important information, freebie from the bank . A money bank, not a bank of battery. A gift from a financial institution. A external USB batery p...
by pksato
Tue Sep 01, 2015 12:59 am
Forum: General discussion
Topic: Checking battery usage of a power bank.
Replies: 14
Views: 10422

Re: Checking battery usage of a power bank.

Hi, AmericanPi? You can't connect a battery bank direct to RPi. To use a battery pack to power RPi (and others) need to normalize battery output voltage. This is done by a electronic circuit called voltage regulator. Also called power supply circuit, module, unit, etc, DC to DC converter. On RC comm...
by pksato
Tue May 19, 2015 6:23 pm
Forum: General discussion
Topic: Stepper motors
Replies: 10
Views: 4033

Re: Stepper motors

Hi, complementing answer... The angle are absolute (from fixed point) or relative (from last position)? Absolute movement, like on printers, is done using a reference point, a switch on start point. Step motor have a two basic operation, a full step (one coil at time) and a half-step (two coils at t...
by pksato
Fri May 15, 2015 11:46 am
Forum: General discussion
Topic: Is Raspberry Pi 2 a good solution for my business?
Replies: 13
Views: 1988

Re: Is Raspberry Pi 2 a good solution for my business?

Hi, As cited, have lots of solutions to use RPi as digital signage device. RPi is small to put inside TV set. If correct configured, Linux is very secure, not need a external firewall. Probable, you can not have access to install location router/firewall to configure a port forward, or most rare, a ...
by pksato
Thu May 14, 2015 12:08 pm
Forum: General discussion
Topic: Type of Ethernet cable
Replies: 3
Views: 4865

Re: Type of Ethernet cable

Hi, Any standard ethernet cat5/cat6 cable can be used. Patch cords that come with routers and other similar devices can be used. If led link status is on on both devices (or software indication), cable is ok. But, need to set ip manually. On windows (mac and linux with advanced gui) easy way is to e...
by pksato
Wed May 06, 2015 11:44 am
Forum: General discussion
Topic: wvdial ATDT*99# ERROR Invalid dial command
Replies: 3
Views: 8085

Re: wvdial ATDT*99# ERROR Invalid dial command

Hi,
try this parameter on wvdial configuration

Code: Select all

Dial Command = ATD
SIM card have a pin lock set?
by pksato
Tue Apr 28, 2015 12:22 pm
Forum: Off topic discussion
Topic: Bad solder on my new RPi 2
Replies: 2
Views: 854

Bad solder on my new RPi 2

Hi, Yesterday I received my Raspberry Pi 2, on a visual inspection I noted a solder bubble. https://lh3.googleusercontent.com/-rWxeXOrh0VI/VT6L6xVQGCI/AAAAAAAAC_E/v1Nhouv-y88/s800/rpi2-ubox-13.jpg Click Is pin 19, GPIO 10 or MOSI. I make some clean up using knife before first power up. RPi2 is worki...

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