Gerben
  • Member for 8 years, 7 months
  • Last seen more than a month ago
  • Netherlands
20x4 LCD with Python - Threading because of different update intervals
1 votes

Just also update the time, while you are scrolling. s = {"text":lcd_text, "line":4} send_to_pipe(s) hour = time.strftime("%H:%M:%S") date = time.strftime("%d.%m.%Y") s = {"text":date + " " + hour, "...

View answer
ws2801 Wiring Problem?
Accepted answer
0 votes

The labeling is the same as on the left of the next chip in the strip. The red and black cable is for power. Where red is 5V, and black is ground. You can't us the 5v on the GPIO for power, as 5 ...

View answer
Power on from idle with gpio3, undocumented?
Accepted answer
4 votes

It's called "wake from halt". Some info can be found at here. This feature is implemented in the bootloader.

View answer
Mult-head micro-usb cable
3 votes

You can definitely make you own. You can either cut up and existing micro usb cable, and solder the red and black (not always though) to a central (thicker) cable. You can also buy the plugs ...

View answer
Using incrontab to read GPIO's
0 votes

You need to be root to execute those commands. You current crontab is executed as the pi user. Put the command inside the root's crontab instead by using sudo crontab -e As to the inverted input ...

View answer
Connecting RTC DS1037, Pin 5 already occupied
Accepted answer
2 votes

The RTC uses pin 5 as an output, for the SCL signal. But you want to use it as an input. This could be difficult, and could even damage the Pi (if SCL is 3.3V and you press the button you'll be ...

View answer
Interrupting a Program with a Button
2 votes

import shlex, subprocess while True: command_line = "sudo ffmpeg -i \"" + q3 + "\" -f s16le -ar 22.05k -ac 1 - | sudo ./pifm - " + str(freq) args = shlex.split(command_line) p = subprocess....

View answer
Is the RPi enough to host a web application with pictures and videos?
Accepted answer
1 votes

Yes. It's even cheaper that shared hosting. It will cost you more time to setup, and maintain though. But you might consider that a learning experience. HD-video might be pushing it a bit, but normal ...

View answer
Can I perform a total backup of my system on an image file?
2 votes

Yes you can do that. I use it to deploy a setup to multiple Pis, without have to reinstall an setup every Pi individually. When using dd I think I just swapped the if and of paths. So something like ...

View answer
Are there any GPIO pins guaranteed to stay low during startup?
1 votes

By default the pins are inputs and therefor floating (except the I2C and UART pins). Why not flip the required value? You just enable the internal pull-up on the pin on the Mega, and have it wait ...

View answer
Is it okay to operate relay boards with less than voltage specified?
Accepted answer
1 votes

The relay board in question has to power inputs, VCC and JD-VCC. The person tells it's okay to put 3.3V on VCC. But you still need 5V on JD-VCC. This 3.3V is only used to power the opto-couplers. ...

View answer
Is there any generic cheap RF module
0 votes

Most receivers require a microcontroller on the receiving end. The XBee already has a micro on board, so you can use it to directly turn on/off a pin on the xbee. If you don't want to have to ...

View answer
Raspberry Pi and Arduino communicate over RF?
5 votes

Don't buy those crap receivers and transmitter. At least pick one that has a crystal. The ones you linked to just provide the modulation of the signal. You'll have to implement a protocol yourself. ...

View answer
Raspberry Pi to Arduino protocol
1 votes

Just use serial, and add an individual Select line (similar to the CS in SPI) to every Arduino. Just make it so that the arduino ignores all serial input, and queues all output, if his Select line is ...

View answer
making serial connection to my electronic dictionary?
1 votes

You'll have to check the voltage on the TXD and RDX lines. The Pi only allows upto 3.3V. Other than that you can just connect the TX on the Pi to the RX on the dictionary, and vise versa, and the ...

View answer
SD Image won't fit on SD Card
6 votes

Indeed not all SD cards are the same exact size. You'd have to shrink the partition to make it fit on the smaller SD. I had a similar problem myself. What I did was have a separate SD with (in my case)...

View answer
I want to switch power for a led strip
2 votes

The ws2801 will indeed still use power, even when all leds are set to zero. Relay is the safest as it isolates the power of the led-strip from the pi. You'd need a very beefy transistor to switch 1A ...

View answer
Using a Pi as an EEPROM programmer
0 votes

This is a 5V device, so if you want to read from it, you'd need to convert the devices output voltages to 3.3V. Even if you don't want to read, you might have to do that. Secondly, to erase the chip, ...

View answer
Working with Raspberry Pi having only a laptop and a table (no extra monitor)
0 votes

Do you have a TV? Just plug it into the TV using either HDMI or Composite (or use a composite to scart plug).

View answer
Logic converter for relay module or extra resistors and transistors?
3 votes

You don't need any additional hardware. The board uses active low optocoupler to switch on the relay. But since the Pi is 3.3V, when the Pi put a pin high (3.3V). But if the relay board is powered ...

View answer
GPIO button to control backlight on PiTFT
3 votes

You can use something like this python script, to poll the input, and to run the toggle-backlight script when pressed. #!/usr/bin/python import RPi.GPIO as GPIO import time import subprocess GPIO....

View answer
Open Door with RPi and RITTO TwinBus Digital Door Bell System
Accepted answer
1 votes

So you want to read out the LED, and be able to simulate a button press? Safest way would be to use a light sensor to read the LED, and a relay to trigger the button press. (These units seem to be ...

View answer
More Software PWM
0 votes

The default RPi.GPIO python library already supports DMA PWM on all pins. See http://sourceforge.net/p/raspberry-gpio-python/wiki/PWM/ for documentation. edit RPi.GPIO doesn't use DMA. I just checked ...

View answer
Using the Raspberry Pi Cam at 110 degrees Celsius
1 votes

At $32,- I'd just try, and see if it works. Camera's that are designed for those kinds of conditions will probably cost into the hundreds if not thousands of dollars. You could try putting the board ...

View answer
Raspberry to power on Arduino
1 votes

Just connect the Arduino a mostfet or power-transitor, to the 9V battery. Have the Pi control whether or not the arduino gets 9V by connecting a GPIO pin to the Gate/Base of the mostfet/transitor. ...

View answer
Will the RaspberryPi Operate Correctly in a refridgerated, 60*F (15*C) Temperatures?
3 votes

That temperature shouldn't be a problem. Just watch out for humidity. Especially when you remove it from the cold environment and put it in the warm one. Water vapor in the warm air will condensate on ...

View answer
What servo motor and mechanism to move the whole Raspi, its camera and case?
0 votes

Servo's can do that, but you have to make sure it has enough range. Most won't do 360degrees. Servo's however require some addition circuitry, to make them stop moving. You don't want jerkiness, when ...

View answer
Powering external hdd exclusively from sector
3 votes

You have to use the solution that is right in the middle of both. Use the layout as per the first image, but also connect the ground to the pi. So the ground goes to both the Pi and the external ...

View answer
Using raspberry pi to take wireless signal and send it out onboard nic
1 votes

If you want to turn your Pi into a wireless accesspoint, you can follow this tutorial: http://learn.adafruit.com/setting-up-a-raspberry-pi-as-a-wifi-access-point/overview

View answer
HDMI not functioning
Accepted answer
3 votes

I think you are out of luck. A DVI cable has lines for both digital, and analog signal. The Pi will only send data over the digital lines, while you monitor (being a VGA monitor) only listens to the ...

View answer