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by pksato
Tue May 03, 2016 8:18 pm
Forum: General discussion
Topic: How to compute voltage?
Replies: 7
Views: 1162

Re: How to compute voltage?

Hi,
Voltage divider coefficient make more sense.
I forgot it to analyze from voltage divider perspective.
Now, on my equation, is not times 2, is times 2.048. :)
by pksato
Tue May 03, 2016 7:55 pm
Forum: General discussion
Topic: RPi-Windows File Transfer via USB Stick
Replies: 12
Views: 3101

Re: RPi-Windows File Transfer via USB Stick

Hi, Linux writing to NTFS is not recommended. Even using NTFS-3G , file system become "unclear". In this case, when plug on windows, It ask to run check disk. On raspberry pi, before mount, open a terminal and run. sudo ntfsfix /dev/sda1 If not have a critical error report, remove and plug on window...
by pksato
Mon May 02, 2016 12:57 pm
Forum: General discussion
Topic: How to compute voltage?
Replies: 7
Views: 1162

Re: How to compute voltage?

Hi, UniPi documentation not mention how read voltage. Have a text to read resistance, but need to know voltage. From MCP3422 documentation. At 16bits, and VI- connected to GND (positive reading), and 1x gain. Vread=(Vmax/32767)*read (10/326767)*9504=2.900V 12% of error. What is the coefficient store...
by pksato
Sat Apr 30, 2016 11:45 am
Forum: Português
Topic: SMS Raspberry Pi 3
Replies: 5
Views: 1727

Re: SMS Raspberry Pi 3

Veja o gammu eo wammu http://pt-br.wammu.eu/ Basta instalar o gammu-smsd apt-get install gammu-smsd E ler a documentação para realizar a conexão com o modulo GSM. Antes veja a compatibilidade com o modulo GSM em uso. Ou, se tiver acesso a internet, pode configurar um alerta via sms no gmail (e outro...
by pksato
Sat Apr 30, 2016 11:33 am
Forum: General discussion
Topic: Linear power supply for Pi3 and Hifiberry Digi+
Replies: 1
Views: 1537

Re: Linear power supply for Pi3 and Hifiberry Digi+

Hi,
Digi+ is a S/PDIF audio output "hat".
And have option with full galvanic isolation of the electrical coax output.
And a optical output.

Since it is a pure digital output, noise from power supply or other noise source not affect audio quality.
by pksato
Tue Apr 26, 2016 4:50 pm
Forum: General discussion
Topic: Analogue PAL TV on Raspberry Pi
Replies: 10
Views: 3011

Re: Analogue PAL TV on Raspberry Pi

Hi, OP can be asking about SDR (Software Defined Radio) solution to watch analog TV (or even digital). http://www.rtl-sdr.com/analogue-tv-with-rtl-sdr/ For correct demodulation need a SDR hardware capable to sample at 10Mbps. And lots of processing. And a RF front end to tune VHF and UHF bands. If w...
by pksato
Thu Apr 21, 2016 3:25 pm
Forum: General discussion
Topic: RPi 3 composite does not work
Replies: 11
Views: 3291

Re: RPi 3 composite does not work

The screen does turn on however and i get a flickering screen of all colors with a very faint image of part of the desktop and the image is just going wild. Can someone please help me out. Can be a wrong cable. Not all cable works, need a correct 4 section pin plug and wiring. Check you cable wirin...
by pksato
Fri Apr 01, 2016 12:10 pm
Forum: General discussion
Topic: How to prevent Raspberry Pi to shutdown using watchdog?
Replies: 3
Views: 1135

Re: How to prevent Raspberry Pi to shutdown using watchdog?

Hi, Shutdown process disable watchdog. Its is not a system fault, is a legitimate system of. I suggest to disable stop of watchdog daemon of shutdown process. I don't sure (check documentation of distribution in use), but this command remove watchdog from runlevel 0 (halt) update-rc.d watchdog stop ...
by pksato
Thu Mar 31, 2016 3:06 pm
Forum: General discussion
Topic: transfer file from pi to pc automatic help
Replies: 6
Views: 2791

Re: transfer file from pi to pc automatic help

Can use rsync. install rsync and start the daemon. install some rsync client on windows. Suggestion: http://www.aboutmyip.com/AboutMyXApp/DeltaCopy.jsp To install sync on raspbian: sudo install rsync sudo nano /etc/default/rsync change RSYNC_ENABLE=false to RSYNC_ENABLE=true save file. start rsync s...
by pksato
Thu Mar 31, 2016 2:57 pm
Forum: General discussion
Topic: barcode scanner Help!!
Replies: 9
Views: 1592

Re: barcode scanner Help!!

Hi,
We need more details about this barcode reader.

But, most SOHO barcode reader emulate a keyboard. Not need any special driver. Any system that support USB HID can work.
If is this case, it work on raspberry pi.

Industrial barcode can have rs232, rs485, i2c, isp or other interface bus.
by pksato
Wed Mar 30, 2016 8:08 pm
Forum: General discussion
Topic: What to do when you have a prototype ready?
Replies: 7
Views: 1447

Re: What to do when you have a prototype ready?

Hi, It is for you use only? Transfer to a veroboard, stripboard or other type/name of standard pcb board. Or, make a hand draw pcb. (For a simple circuit) If want to sell, design a PCB board that flow PCB industry specifications. Have a lots of free, foss and commercial electronic computer aid desig...
by pksato
Fri Mar 25, 2016 5:59 pm
Forum: Beginners
Topic: CONCERN? 115 Volt vs UK 240V
Replies: 7
Views: 916

Re: CONCERN? 115 Volt vs UK 240V

Do I need to be concerned with 115 Volt USA, vs UK United Kingdom 240V. I am in USA. Also, you need to concern about ac mains frequency, 60Hz on USA and 50Hz on UK. If is about power supply, if it use a switching, most work on large range of voltage and frequency. Just check label on unit. Please, ...
by pksato
Fri Mar 25, 2016 5:15 pm
Forum: General discussion
Topic: autoredirect all pages on rpi ap
Replies: 6
Views: 1285

Re: autoredirect all pages on rpi ap

Hi, correct answer to this question is captive portal. Captive portal is a system that intercept connection and display some advertising, and request identification to continue accessing internet. But, today captive portal have a trouble, most web access is done using https. And intercepting https b...
by pksato
Fri Mar 25, 2016 4:36 pm
Forum: General discussion
Topic: php error 500
Replies: 2
Views: 1792

Re: php error 500

i have set up a apache2 web server on my pi and install php5 and all. i places a simple php in the server and when i run it, it says, <pi-ip-address> page isn’t working <pi-ip-address> is currently unable to handle this request. 500 how do i fix this ? Hi, Sorry. I don't know how fix it. I don't kn...
by pksato
Fri Mar 18, 2016 12:31 pm
Forum: Português
Topic: Ligar reles com Raspberry Pi
Replies: 11
Views: 8959

Re: Ligar reles com Raspberry Pi

Olá Pessoal, Obrigado pelas vossas publicações, decidi fazer conta para esclarecer algumas dúvidas, 1) Alguém pode disponibilizar a ficha técnica da placa de 8 reles, preciso de saber a frequencia máxima de sinal, tenho um sistema que imite sinais a 3000 até 5000HZ, precisava saber se a placa de re...
by pksato
Sat Feb 27, 2016 12:28 pm
Forum: General discussion
Topic: Need Help. What size screen does Pi B Support?
Replies: 5
Views: 1079

Re: Need Help. What size screen does Pi B Support?

Hi, Hi, I'm looking to set up a Pi Wall using 6 HDTV's. I want to use 32"-42" screens. I was wondering, would the raspberry pi model b support a 42" screen? If not, would it support a 32" screen, and if so, what resolution? I will be using HDMI cables and I have read the instructions on setting up t...
by pksato
Fri Feb 26, 2016 6:23 pm
Forum: Beginners
Topic: Audio Selector
Replies: 1
Views: 340

Re: Audio Selector

HI, You not need a raspberry pi to do it. Its is very simple task. Can do using a analog circuity or some µC (8pin AVR or PIC) with ADC. Raspberry Pi don't have ADC, need a external module. Analog or µC circuity consume few µA (on stand-by), RPi need hundreds of mA. Both, Analog and µC have same bas...
by pksato
Fri Feb 26, 2016 12:26 pm
Forum: General discussion
Topic: How to connect a 10v dc fan to the raspberry pi 2
Replies: 11
Views: 1742

Re: How to connect a 10v dc fan to the raspberry pi 2

Hi Scott, So i've been thinking, based on the GPIO layout that is used on the pi 2, I can see that there are 2 5v outputs and one ground. Is there a way that I could connect one of those larger 10v DC fans to the raspberry pi instead of this small and noisy 5v fans?. Voltage is a electric potential ...
by pksato
Mon Feb 22, 2016 1:13 pm
Forum: Beginners
Topic: Touch capable through composite??
Replies: 3
Views: 517

Re: Touch capable through composite??

Hi,
display panel and touch panel are separated device.
If you can make touch panel to work, not need to sit on from of monitor.
You can not use touch on working AVH-x4700BS.
Removed panel can be work if use some standard protocol, sw and hw. And proper wiring.
by pksato
Mon Feb 22, 2016 11:35 am
Forum: General discussion
Topic: Grounding static electricity.
Replies: 7
Views: 1904

Re: Grounding static electricity.

Normally I ground myself on a radiator pipe before handling my pi, so as not to static shock it, but someone mention touching the outer casing of the pi's usb connector because its connected to the pi's ground. If I touch the usb connector or a ground pin will it do for static electricity? Hi, You ...
by pksato
Sat Feb 20, 2016 1:01 pm
Forum: General discussion
Topic: clock to 7 segment display
Replies: 18
Views: 2570

Re: clock to 7 segment display

Hi, This is a 5MHz quartz crystal. Can be uses a filter, as oscillator to generate pulses to drive some digital circuity (clock pulses). As clock generator, it pulses at 5 million times per second. To get 1 pulse per second, need to divide per 5 million. Two 74HC4060 can be used as divide, with extr...
by pksato
Fri Feb 19, 2016 7:28 pm
Forum: General discussion
Topic: OPENVPN
Replies: 3
Views: 804

Re: OPENVPN

Hi,
If openvpn client not have fixed ip, install and configure fail2ban.
knockd also is a option to control access.
by pksato
Fri Feb 19, 2016 6:11 pm
Forum: General discussion
Topic: Transparent bridge firewall with iptables
Replies: 6
Views: 4607

Re: Transparent bridge firewall with iptables

Hi, A long time ago, I implement similar bridge function (not on rpi), information below can be outdated. Enable ip forward echo "1" > /proc/sys/net/ipv4/ip_forward (or use sysctl) iptables need to address physical interface, like on this examples. iptables -I FORWARD -m physdev --physdev-is-bridged...
by pksato
Thu Feb 18, 2016 5:02 pm
Forum: General discussion
Topic: Pi to Pi Communication
Replies: 3
Views: 564

Re: Pi to Pi Communication

Hi RPi is a computer. :) A small one, but is a computer. To send a file, you can use scp or sftp, with pre shared key. Or via http post, using curl (or other) on sender side, and a cgi application on receiver (server). cgi or commom gateway interface can be write in java, php, node.js, python, etc. ...
by pksato
Thu Feb 18, 2016 4:48 pm
Forum: General discussion
Topic: Remote access
Replies: 5
Views: 824

Re: Remote access

Hi, I not sure, but, I think that mac only see rpi or other if have some service to access. Service like, a file sharing using samba (nfs, ftp), printer, etc. You need to access RPi from mac to do what? To access shell via ssh not need to finder find rpi, only need current rpi ip or name assigned to...

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