Raspberry Pi Forums

Ferdinand

WARNING The solenoid in your link is meant for (dc) battery operated irrigation controllers (9V). It is not a ac solenoid. This solenoid should work with your mosfet without problems. I think you made a mistake how this solenoid operates. Use a H bridge to latch and unlatch your solenoid by swappin...

Ferdinand

Hi equals, Do you have an ohmmeter to measure the coil resistance? You may also measure the dc current through your relay. I except that the dc current is much higher then 0.14 amp which is an ac value. The resistance value specified is a ac impedance, dc coil resistance is much lower. That could ex...

Ferdinand

Hi Florisjan, Some remarks: The swap of high/low in line 11/16 was because I used a two way (no +/-) capacitor, allowing me to charge it and read it out with the same gpio, so a 3.3v wire is not necessary. You may use both methods with electrolytic/ceramic capacitors. One side of the capacitor is al...

Ferdinand

Hi Florisjan, I'm very sorry to say but you did not post your latest py script because this script will never run. You have made a couple of mistakes: 1) ":" is missing in line 16 2) It is try and except (you need both). Remove try statement and adjust indentation in succeeding lines, see below 3) i...

Ferdinand

frankenberry wrote: I now have a working script. Although, I do not understand why it works...

NCLAB has a very good ebook "Introduction to Python Programming"
and re(read) the excellent cronHOWTO post of RaTTus.

Ferdinand

RaTTuS wrote: crontab -e
* */4 * * * /path/to/python /path/to/script arguments >/tmp/redirection.ouput.file

It's 0 */4 * * * /path/to ...
Otherwise 60 extra lines will be made in an outputfile.
I tested it.

Ferdinand

Hi frankenberry, Use crontab -e to edit your pi crontab: @reboot /usr/bin/python /home/pi/CronJobs/testPython.py >> /home/pi/time.txt 0 */4 * * * /usr/bin/python /home/pi/CronJobs/testPython.py >> /home/pi/time.txt This will add/create a line in time.txt directly after a reboot and add a line every ...

Ferdinand

Hi radenblazed, Don't connect these level shifters directly to your relay channels, it could fry your pi! A relay channel current is 15 to 20 mA. See your sainsmart datasheet. A gpio port can sink/source about 16 mA max. If you activate more then 3 relays, 45 - 60 mA total, your are exceeding the ma...

Ferdinand

Hi fusionwerks, Try this code: #!/usr/bin/python import time import RPi.GPIO as GPIO import sys # Hex characters 0..9,A..F # x = pause hex_string="0123x456789ABCDEFxxxABC" time_delay = 0.5 time_delay_x = 0.5 relay_pin = [2,3,4,17,27,22,20,9,11,5,6,13,19,26,21,20] GPIO.setwarnings(False) GPIO.setmode...

Ferdinand

Hi bdrmachine,

Your first line in install.sh must be:
#!/bin/bash
then
chmod 700 install.sh
then
./install.sh

Ferdinand

Hi AidanTek, The coil current, in this case, is about 1.4 Amp (typical specs of L298). However, the power dissipation (L298) is about 4.6 W for 1 stepper motor. If both motors are running then the max. dissipation is 9.2 W. The conclusion is that you need to mount the L298 bridge on a well designed ...

Ferdinand

Hi AidanTek,

Which stepper motor are you using?

Perhaps this link can provide you more info:
viewtopic.php?f=63&t=157745

Ferdinand

Hi eaglehack, I did some tests. My python program runs fine after a reboot (flashing a led). A couple of options: 1) create a new account/profile with sudo rights and remove "pi" account/profile. Don't forget to make a backup of important files! or 2) Maybe your system has been corrupted for some re...

Ferdinand

Hi willbobby, I modified your program a little bit. I put a random function in it. Success with your program, nice example!!! #!/usr/bin/python # author : willbobby # raspberry pi forum : Help with Python code # date : Nov 12, 2016 import random import os import time loop = True while loop: os.syste...

Ferdinand

Graag gedaan.
Succes!

Ferdinand

Hallo fnuus, Ik heb een paar kleine aanpassingen gemaakt. De timers hebben nu een vaste tijd die je bovenaan, in het script, kan aanpassen. De namen zijn: t_aan_red = 1 en t_aan_yellow = 0.2 Verder heb ik wat commentaar toegevoegd. De rode leds knipperen met een vaste tijd van 1 sec De gele leds kni...

Ferdinand

Ha fnuus,

Ik ga ermee aan de slag.

Ferdinand

Hallo fnuus, Hoe heb jij de leds aangesloten? Manier 1) 3.3 V ----REDLED----weerstand----pin x of manier 2 pin x -----REDLED------weerstand---GND x stelt hier pin 31,33,35 of 37 voor. Ik heb in de software manier 1 gebruikt. Wanneer jij manier 2 gebruikt moet je dat in de software wijzigen. Pin 37 w...

Ferdinand

Hi fnuus, Ik heb jouw programma een beetje aangepast en gebruik gemaakt van de gegevens uit jouw eerste post. De leds heb ik verplaatst naar de pinnen 31,33,35 en37 omdat de pinnen die jij opgaf in gebruik zijn bij het os. Gebruik bij voorkeur vrije pinnen. Ik hoop dat je hier wat aan hebt en anders...

Ferdinand

Hallo Naaamgenoot, Je geeft bij de start van het programma aan flash_yellow = True Dan een if statement waarin flash_yellow wordt getest Wanneer dat waar is dan 15 x knipperen Na 15x knipperen geef je aan flash_yellow = False De gele leds knipperen dan niet meer bij de volgende doorgang. Dan: functi...

Ferdinand

Hallo fnuus, Het beste om hier functies in te zetten. Functie 1) 2 rode leds die 50 x knipperen Functie 2) Gele led aan, 10 sec. wachten en dan gele led uit Functie 3) Rode leds aan die zoveel x moeten knipperen. Is nu het programma afgelopen of draait het soms in een loop? In een functie aanroep ka...

Ferdinand

Hi,
try this command on a testimage!!!
Use the following command to edit the root crontab:
sudo crontab -e
add the following line to your crontab.

Code: Select all

@reboot sleep 60;/sbin/shutdown +120

don't forget the sleep command, otherwise you will have a login problem!!!

Ferdinand

Hi,

Follow this link:
http://pcsupport.about.com/od/commandli ... ommand.htm

Than create a script to start the shutdown command at after rebooting.
Follow the discussion on the pi-forum.

Ferdinand

Hi mojorizing,

The profile of synaptic has been corrupted for some reason.
Remove 'as root' the .synaptic file in the folder /root
The easiest way to remove this file is by using midnight commander (mc).
sudo apt-get install mc
Reboot your system after modification.

Ferdinand

Great news, next challenge!!!

Search found 236 matches

Re: Solenoid wiring (did I do it right?)

Re: Solenoid wiring (did I do it right?)

Re: LDR readout not working properly on RPI 3

Re: LDR readout not working properly on RPI 3

Re: Run Python Script at Startup

Re: Run Python Script at Startup

Re: Run Python Script at Startup

Re: GPIO not working as expected

Re: anyone willing to help me write a python script

Re: Running file

Re: Stepper Motors and the L293D

Re: Stepper Motors and the L293D

Re: command not running in rc.local but works in terminal

Re: Help with Python code

Re: Led loop maken

Re: Led loop maken

Re: Led loop maken

Re: Led loop maken

Re: Led loop maken

Re: Led loop maken

Re: Led loop maken

Re: Shutdown after set period

Re: Shutdown after set period

Re: Synaptic Package Manager - no background

Re: Raspberry Pi not running crontab script on startup