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by ghp
Sun Dec 01, 2019 9:08 am
Forum: Python
Topic: MCP3204 does not give any lecture of temp measurements with lm35, it worked before i actualized
Replies: 1
Views: 64

Re: MCP3204 does not give any lecture of temp measurements with lm35, it worked before i actualized

Difficult to follow your code as the indendation is lost. See https://www.raspberrypi.org/forums/view ... 32&t=84477
What did you change ? "it worked before i actualized".
by ghp
Mon Nov 18, 2019 8:23 pm
Forum: Python
Topic: How to get LED's to turn off immediately?
Replies: 1
Views: 136

Re: How to get LED's to turn off immediately?

Without the use of threads, there is no very simple implementation. Here a proposal to use something like a time-slot-solution. In a loop, time ticks are propagated to a LED class which keeps start- and end times. As the loop runs quite fast a button press almost immediately stops the loop. The code...
by ghp
Tue Nov 05, 2019 10:19 pm
Forum: Python
Topic: Voltage divider false event detect
Replies: 9
Views: 1022

Re: Voltage divider false event detect

for switching my lights i'm using a 24v signal circuit which triggers a relay at the mainboard If there is a relay in the 24V-circuit in parallel to the voltage divider, then there might be a problem with high voltage spikes when the relay is switched off. Do you use a diode protection "flyback" ci...
by ghp
Sat Nov 02, 2019 3:02 pm
Forum: Python
Topic: 8 IR receivers on 8 GPIO pins
Replies: 6
Views: 1305

Re: 8 IR receivers on 8 GPIO pins

I once used aluminum foil where a sheet of paper was transmitting too much of IR light. To prevent electricl shortcuts, I glued it between two sheets of paper.
by ghp
Tue Oct 29, 2019 8:08 pm
Forum: Python
Topic: Python script at boot can't find pytz
Replies: 2
Views: 280

Re: Python script at boot can't find pytz

Possibly the path wrong ?
ExecStart=usr/bin/python3 should be ExecStart=/usr/bin/python3 ??
by ghp
Sun Oct 27, 2019 8:46 am
Forum: Python
Topic: [Solved] DCT update value from nested list
Replies: 3
Views: 466

Re: DCT update value from nested list

Hello, in this json is a slight problem: missing ',' after """{"point": "2", "start": "11.00", "stop": "14.35", "available": 1}""". import json x = """ { "timestamp": 1412282459, "res": [ { "group": "1", "catlist": [ { "cat": "1", "start": "none", "stop": "none", "points": [ {"point": "1", "start": ...
by ghp
Wed Oct 23, 2019 6:42 pm
Forum: Python
Topic: Robot with stepper motor 28byj-48
Replies: 4
Views: 590

Re: Robot with stepper motor 28byj-48

Hello, these stepper motors have an internal gear box with prox 1:64 ratio. The internal stepper needs to make 64 turns internally to perform one external turn on the axle. I once disassembled a defect motor and the internal stepper is really tiny. In the datasheet found in the net the frequency is ...
by ghp
Sun Oct 20, 2019 5:55 pm
Forum: Python
Topic: Turning on LED strip and printing with button push
Replies: 7
Views: 821

Re: Turning on LED strip and printing with button push

There are some slight problems in your code. The line numbers given are related to the code given in your first post here. Your print statements are not very precise. Line 65: The """print ("led on")""" is indented two levels. You have gotten 32 times "led on" printed ? Line 87: The """print("button...
by ghp
Sun Oct 20, 2019 9:17 am
Forum: Python
Topic: Turning on LED strip and printing with button push
Replies: 7
Views: 821

Re: Turning on LED strip and printing with button push

Hmm, what is 'it' in this context ? Give more details !
The code worked in initial revision posted ?
by ghp
Sat Oct 19, 2019 7:55 pm
Forum: Python
Topic: Turning on LED strip and printing with button push
Replies: 7
Views: 821

Re: Turning on LED strip and printing with button push

In the led_on() method, there is a line
strip.setPixelColor(x, Color(255,0,0))

Try writing a similiar method led_off() where this line is
strip.setPixelColor(x, Color(0,0,0))
by ghp
Sat Oct 19, 2019 7:19 am
Forum: Python
Topic: Random Pin Selection
Replies: 1
Views: 505

Re: Random Pin Selection

Think there is no [random pin selection]. But with [random] combined with [pin selection], there are solutions: Add your pin numbers into an array. Then select random number and pick the related pin number from the array. ## import RPi.GPIO as GPIO ## setup GPIO... import random # just some sample n...
by ghp
Wed Oct 16, 2019 5:33 pm
Forum: Python
Topic: Pyserial output equals input
Replies: 12
Views: 727

Re: Pyserial output equals input

Here some code which (in various flavors) I use with my serial devices. It uses a thread to receive and display data independent from the sending task. #!/usr/bin/python3 # execute with python 3 import threading import time import serial import sys # use one of the following strings eol_string = "\r...
by ghp
Mon Oct 07, 2019 6:15 pm
Forum: Python
Topic: [Update]Controlling the Microsteps of Stepper motor + Python3
Replies: 25
Views: 1351

Re: Controlling the Microsteps of Stepper motor + Python3

as far I can see from the datasheet, there are switches at the side of the device which define the microstep behavior. These switches (most possibly ) can't be modified by code, but only manually. You own this device, you can see these switches ? in pseudocode, the logic for one revolution is: N = 2...
by ghp
Wed Oct 02, 2019 6:42 pm
Forum: Python
Topic: [Update]Controlling the Microsteps of Stepper motor + Python3
Replies: 25
Views: 1351

Re: Controlling the Microsteps of Stepper motor + Python3

Hello, when looking to the datasheet of the device, there are switches which define the microstepping behavior. SW5, 6, 7, 8 on, off, off, off should give 256 microsteps. When your python code controls the rotation, there should be a considerable slowdown. As far I can see, there is no software cont...
by ghp
Sat Sep 28, 2019 6:18 pm
Forum: Python
Topic: Extracting data from ADXL345 code
Replies: 1
Views: 154

Re: Extracting data from ADXL345 code

Hello, first idea is alway something like what_is_this = adxl.read_one() print( what_is_this ) When looking into the source code, the method is implemented as def read_one(self): count, data = self.pi.spi_xfer(self.h, self.READ_DATA) if count == 7: x = ct.c_int16(((data[2] << 8)) | data[1]).value * ...
by ghp
Tue Sep 24, 2019 5:17 pm
Forum: Python
Topic: Pregunta puertos COM Raspberry - Question COM Port.
Replies: 2
Views: 187

Re: Pregunta puertos COM Raspberry - Question COM Port.

Think that udev rules can help with this. See for example https://www.silabs.com/community/interface/knowledge-base.entry.html/2016/06/06/fixed_tty_deviceass-XzTf Although I have to admit I never used this on my own. In my projects, I have implemented a unique ID string in EPROM of arduino. The appl...
by ghp
Mon Sep 23, 2019 7:41 pm
Forum: Python
Topic: Run more scripts forever
Replies: 6
Views: 397

Re: Run more scripts forever

One possible solution is to use a shell script which first starts script 1, then script 2. This needs script 1 to terminate before script 2 is executed. The while true; executes this in a forever loop. #!/bin/sh while true; do python3 script_1.py python3 script_2.py done save as exec_loop.sh and exe...
by ghp
Mon Sep 23, 2019 6:43 pm
Forum: Python
Topic: LED-button with detected pressed time
Replies: 10
Views: 407

Re: LED-button with detected pressed time

... and possibly the indentation is wrong ? buttonTime = time.time() - start_time if buttonTime >= 4: writetotxtfile("Long Pressed1","text1.txt") elif buttonTime >= 2: writetotxtfile("Medium Pressed1","text1.txt") elif buttonTime >= .1: writetotxtfile("Short Pressed1","text1.txt") Should be more lik...
by ghp
Fri Sep 20, 2019 9:49 pm
Forum: Python
Topic: Send datas to an arduino with pySerial
Replies: 5
Views: 351

Re: Send datas to an arduino with pySerial

Hello, raw_input is for python2. Better to use python 3 with input(). I have prepared a small python code along your proposal, which also reads in what arduino sends. # execute with python 3 import serial import threading import time s = serial.Serial("COM9", 9600) s.timeout=0.3 loop = True def rece...
by ghp
Tue Sep 17, 2019 5:41 pm
Forum: Python
Topic: Python curses issue
Replies: 3
Views: 195

Re: Python curses issue

Hmm, possibly the reason is that your file curses.py has the same name as the library imported. Rename your file to something different like 'my_project_with_curses.py'.
by ghp
Tue Sep 17, 2019 4:53 pm
Forum: Python
Topic: Read serial port using pyserial problem
Replies: 23
Views: 1295

Re: Read serial port using pyserial problem

Hello, try to check the data using a 'serial terminal' program like "minicom'. sudo apt-get install minicom use with minicom -D /dev/ttyUSB0 Setup port settings (baudrate etc). You should see the remote device deliver data continuously. In your python code, you do not set the baud rate ? https://pys...
by ghp
Mon Sep 09, 2019 7:14 pm
Forum: Scratch
Topic: Raspberry Pi 4 and Scratch 2
Replies: 10
Views: 3137

Re: Raspberry Pi 4 and Scratch 2

Hello, had similiar problems here. Happens here on pi4, scratch2 both when uploading file for a sprite or stage background 'backdrop'. Selection menu opens, pi seems to be frozen in the menu. A ssh-connection to the pi is still working. "top" shows low cpu usage. "killall electron" stops scratch2. E...
by ghp
Sat Aug 31, 2019 5:04 am
Forum: Python
Topic: Help understanding 74HC595
Replies: 3
Views: 306

Re: Help understanding 74HC595

Calling clear() at the beginning of the operations, just after setup(), is needed. This avoids problems by GPIO having unknown state because program is stopped and restarted with again calling setup(). I would propose to change the code a bit. Instead of the block def inputBits(dat): for bit in rang...
by ghp
Sun Aug 25, 2019 8:04 pm
Forum: Python
Topic: ADS1115 I2C audio with python
Replies: 2
Views: 214

Re: ADS1115 I2C audio with python

The ADS1115 is a high precision device but rather slow: "programmable Data Rate:8 SPS to 860 SPS". This means that 430Hz are highest frequency resolvable. Cited from https://physics.stackexchange.com/questions/76463/what-is-the-meaning-of-frequency-of-a-human-voice: "According to the Wikipedia artic...

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