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by rgrbic
Wed Aug 06, 2014 12:53 pm
Forum: Troubleshooting
Topic: power relay external
Replies: 4
Views: 1027

Re: power relay external

You have to put transistors between board and RPi since GPIO cant provide 50 mA
by rgrbic
Wed Aug 06, 2014 7:52 am
Forum: Automation, sensing and robotics
Topic: Oil Tank Monitor Project
Replies: 9
Views: 6239

Re: Oil Tank Monitor Project

Cool project. Maybe pressure sensor can help you in volume determination but this requires closed tank.
by rgrbic
Wed Aug 06, 2014 12:49 am
Forum: General discussion
Topic: Newbie wondering if Pi is right for me
Replies: 21
Views: 2925

Re: Newbie wondering if Pi is right for me

Less components, less likely to go something wrong :)

A microcontroller have ADC built in (you will need it) and do not need sd card to operate in comparison with RPi.
You can connect TFT with touch screen but some Lcd with few buttons can do the work.
by rgrbic
Tue Aug 05, 2014 11:40 pm
Forum: Troubleshooting
Topic: Inteface problem
Replies: 4
Views: 594

Re: Inteface problem

How did you connect your RPi to the display?
by rgrbic
Tue Aug 05, 2014 11:36 pm
Forum: Other projects
Topic: Case Fan - will this work (link in post)?
Replies: 5
Views: 2603

Re: Case Fan - will this work (link in post)?

Yes, you have to use transistor. Third wire on fan is output from speed sensor so you can disregard it. See here how to interface transistor and relays.
by rgrbic
Tue Aug 05, 2014 8:57 pm
Forum: General discussion
Topic: Newbie wondering if Pi is right for me
Replies: 21
Views: 2925

Re: Newbie wondering if Pi is right for me

I suggest you to use microcontroller system, maybe you can start with some arduino board.
by rgrbic
Tue Aug 05, 2014 8:48 pm
Forum: Beginners
Topic: Temp sensor web readout
Replies: 5
Views: 1305

Re: Temp sensor web readout

Maybe this link can help you. In this project sensor readings are periodically sent to the webpage using websockets.
by rgrbic
Tue Aug 05, 2014 8:22 pm
Forum: HATs and other add-ons
Topic: Can RaspPi power Arduino? (yes)
Replies: 19
Views: 22568

Re: Can RaspPi power Arduino?

I am thinking of using Arduino Uno. I found in the past (with a now defunct Raspberry Pi power supply) with my Arduino that it needed a powered hub or it would pull too much current from the RPi and would run right on the limit. (That may be different with a B+). I powered my Uno from RPi without a...
by rgrbic
Tue Aug 05, 2014 7:50 pm
Forum: Automation, sensing and robotics
Topic: Debugging Connected Phidgets Magnetic Field Sensor
Replies: 3
Views: 1031

Re: Debugging Connected Phidgets Magnetic Field Sensor

MCP3008 is SPI ADC, so you should connect it with RPi with 6 wires (MISO, MOSI, CLK, SS, 3.3V, GND)
or I am missing something
by rgrbic
Tue Aug 05, 2014 7:44 pm
Forum: HATs and other add-ons
Topic: Can RaspPi power Arduino? (yes)
Replies: 19
Views: 22568

Re: Can RaspPi power Arduino?

What board are you talking about? You can power it via usb to serial. If you plug an Uno (or Nano, not got any others) into a Pi via USB (like you would a PC if programming it), not only will it power it, the Uno will appears as a serial device in /dev as it has a serial - USB chip onboard. Yes, Un...
by rgrbic
Tue Aug 05, 2014 6:30 pm
Forum: Beginners
Topic: PWM for DRV8825
Replies: 17
Views: 4637

Re: PWM for DRV8825

Or use 555 timer :)
by rgrbic
Tue Aug 05, 2014 6:27 pm
Forum: HATs and other add-ons
Topic: Can RaspPi power Arduino? (yes)
Replies: 19
Views: 22568

Re: Can RaspPi power Arduino?

What board are you talking about? You can power it via usb to serial.
by rgrbic
Sun Aug 03, 2014 9:59 am
Forum: Other projects
Topic: Shutdown Button
Replies: 1
Views: 690

Re: Shutdown Button

This is very useful. Here you can find similar code and schematic. Short button press resets RPi, longer (more than 3 sec) press shutdowns RPi.
by rgrbic
Sat Aug 02, 2014 5:05 pm
Forum: Troubleshooting
Topic: power relay external
Replies: 4
Views: 1027

Re: power relay external

Can you provide more information about the board?
by rgrbic
Sat Aug 02, 2014 5:02 pm
Forum: Beginners
Topic: Rasberry pi port forwarding security
Replies: 27
Views: 7508

Re: Rasberry pi port forwarding security

I guess that with some coding this might be achieved also with F2B (what might not be their planned use case), but then I have doubts if F2B makes sense - instead of taking base building blocks and implement something by using them, I'd add another layer and then try to find various custom paths th...
by rgrbic
Sat Aug 02, 2014 10:03 am
Forum: Beginners
Topic: Rasberry pi port forwarding security
Replies: 27
Views: 7508

Re: Rasberry pi port forwarding security

Hi, Let me mention what I mean with just one simple example. There is a page where the visitor can gain 20-minutes exclusive access to a model train control and observe it via web cam ( http://www.flyfish-tech.com/scratch/ ). This is implemented with ipchains + ipset, the visitor's IP is added in t...
by rgrbic
Fri Aug 01, 2014 7:06 pm
Forum: Beginners
Topic: Rasberry pi port forwarding security
Replies: 27
Views: 7508

Re: Rasberry pi port forwarding security

If you are running ssh, use key based authentication and disable password authentication. Permanently ban ip addresses after unsucessfull login.
by rgrbic
Fri Aug 01, 2014 6:18 am
Forum: Beginners
Topic: Changing permissions for all folders?
Replies: 3
Views: 1205

Re: Changing permissions for all folders?

Use chmod -R
by rgrbic
Thu Jul 31, 2014 8:21 pm
Forum: Other projects
Topic: Security Concerns for a CONNECTED Raspberry Pi
Replies: 3
Views: 1226

Re: Security Concerns for a CONNECTED Raspberry Pi

here is how I tried to improve security of my RPi
by rgrbic
Wed Jul 30, 2014 9:37 am
Forum: Advanced users
Topic: How to control water flow meter via RPi?
Replies: 6
Views: 4459

Re: How to control water flow meter via RPi?

This sensor outputs pulses which should be counted (for example count number of pulses in one second and then use formula to obtain flow).
I think there were some threads on forum about counting with RPi, search for it.
by rgrbic
Wed Jul 30, 2014 7:34 am
Forum: Automation, sensing and robotics
Topic: Boardcomputer for a Motorcycle
Replies: 7
Views: 2478

Re: Boardcomputer for a Motorcycle

Well,you can do it with the following components: - some microcontroller (like atmega328) with additional circuitry (switch, crystal, step down converter, ...) - bluetooth module which connects via UART to microcontroller and is used for communication with mobile phone - circuitry for sensor signal ...
by rgrbic
Tue Jul 29, 2014 6:28 pm
Forum: Automation, sensing and robotics
Topic: Boardcomputer for a Motorcycle
Replies: 7
Views: 2478

Re: Boardcomputer for a Motorcycle

Sounds like interesting projects.
Since you will have different signals (several require ADC, there will be pulse counting, different on/off signals) I suggest you to make additional board with some microcontroller which will sample all necessary signals and send the readings to the Raspberry Pi.
by rgrbic
Tue Jul 29, 2014 6:10 pm
Forum: General discussion
Topic: LED help please
Replies: 91
Views: 11005

Re: LED help please

If you are building aquarium for plants, here are some tips. At first, around 30-50 lumens per litre is considered high luminosity. So, according to the LED datasheet and your aquarium volume you can calculate how much LEDs do you need. For example, some 3W LED gives 250 lumens. For aquarium of 100 ...
by rgrbic
Mon Jul 28, 2014 2:49 pm
Forum: Automation, sensing and robotics
Topic: Stepper motors with external Power Supply?
Replies: 14
Views: 5417

Re: Stepper motors with external Power Supply?

Well I said that the rest of the wiring wasn't important. This image is just something that I found quickly on google. The only part that I'm interested in is if hooking up a power supply in a similar manner will fry the RPi. Since you people are so keen on pointing out every single irrelevant thin...
by rgrbic
Mon Jul 28, 2014 10:37 am
Forum: Automation, sensing and robotics
Topic: Pulse counting / outputing
Replies: 7
Views: 1414

Re: Pulse counting / outputing

You can do it with lm331. Something like:
frequency to voltage ->multiplier ->voltage to frequency

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