Raspberry Pi Forums

ghp

Hello, nice idea for a program. The variable nightmarealert is only defined in the if/else path, but not generally available. Place a default value upfront: nightmarealert = None if type == "F" or "f": print (fairy_story) elif type == "T" or "t": print (tt_story) elif type == "S" or "s": nightmareal...

ghp

Hello,
this module obviously has a comparator 'on board', so not only the bare sensor.
Of course you can use digital output here; possibly you need a voltage divider to adjust the 5V-level to the 3.3V-Level.
Regards,
Gerhard

ghp

Hello, try using the serial output, GPIO14 on the UART. You need to disable serial output from the operating system (raspi-config provides menu to disable).
Then use pyserial. Do not put baud rate too fast for the beginning, 1200 bd and when this is stable then increase.

Regards,
Gerhard

ghp

Hello, just use 'threading'. There are many tutorials on the net, e.g. http://pymotw.com/2/threading/ . Keep in mind that raspberry with python will have limits in pulse frequency generation. Steppers require high pulse rates when running even at moderate rotation rates. One rotation per second, 200...

ghp

Hello, you are doing strange things (sorry). Look at this solution of a small project I called gpio_substitute. It has a src-Folder, where a test.py and test2.py are. rpigpio.png There is also a RPi-Folder with a GPIO.py and an empty __init__file. The first test file is try: import RPi.GPIO as GPIO ...

ghp

Hello, this transistor has Ib=5mA, Ibe=0.9V at Ic=100mA. 100mA is max current continuous. And you have hfe of 200, this is @2mA Ic, but do not rely on this 200. I would place a series resistor between the GPIO and base connection transistor of (3.3-0.9) V/ 5mA which are the saturation values from th...

ghp

Hello, how do you probe the output ? Are you sure that no other programs are running working with GPIO in the background ? And could you give more details on the relais board ? photo, schema, description. And last not least: The P1-13-pin has changed assignment between R1 and R2 of the Pi. If you ow...

ghp

Hello, pt100 (from the headline) or pt1000 (from your text) are temperature variable resistors, about 100 or 1000 Ohms at 0 degree Celsius. The max6675 is designed for a type -K thermocouple. from wikipedia " Type K (chromel – alumel) is the most common general purpose thermocouple with a sensitivit...

ghp

Hello,

the entry is for 'python'. When no other process is using python, then it is tkinter.
Regards,
Gerhard

ghp

Hello,

see http://heppg.de/ikg/wordpress/?p=408
Even in my 'not loaded' environment, the timing is not very accurate. My solution is to use an external slave microcontroller to solve this problem. Costs 4 or 5€ and saves a lot of headache.

Regards,
Gerhard

ghp

Hello,

in a console window, enter 'top'.
'top' is a monitor, which displays processes, cpu per process, memory and some more stuff.

Regards,
Gerhard

ghp

Hello, with regular expressions, this is not a difficult task. a short sample is (not complete) import re data = [ "Humidity: 53.30 %", "Light Level 69 - Dark", "provided altitude: 69 meters, 226 feet", "temperature: 19.46 deg C, 67.03 deg F", "absolute pressure: 1015.54 mb, 29.99 inHg", "relative (...

ghp

Hello, if I am right, this anemometer just provides a reed switch. Did you provide a pullup resistor in your setup, as needed to connect buttons/switches/reeds ? There is a nice tutorial in https://www.cl.cam.ac.uk/projects/raspberrypi/tutorials/robot/buttons_and_switches/ You should have connected ...

ghp

Hello, git is a good choice, but svn is still quite popular. If you plan on a larger scale, you will need to have an own server somewhere on the web for your dev environment. If your project grows, you will need continuous integration (hudson) also. Possibly a ticketing system is needed, and of cour...

ghp

Good news, it is a slow problem. And obviously each of the pins is handled the same way independent of the other pins. I usually try to handle problems like these with state machines. For your problem, the inputs are [0] or [1] and possibly you need some time events. For the pure academic implementa...

ghp

Hello, before making an architecture, some more details needed on timing and number of events per second. Are input signals in second (or more) or in millisecond range ? And how many of these will come in average per second (a few or hundreds) ? Are the signals 'clean' or need debouncing ? If there ...

ghp

Hello,

welcome in the python forum !
Most possibly you need to enable the spi driver. This is best done using

sudo raspi-config

Look into '8, advanced', 'A6, SPI' and enable this. Could be you need to reboot then.

Regards,
Gerhard

ghp

Hello, see http://dev.mysql.com/doc/connector-pyth ... mples.html
This is what I used some year ago to connect to a mysql database.

Hope this helps
Gerhard

ghp

Hello, I was curious to see what happens in this code. Programmed an external pulse generator (100ms high in 500ms period) with an arduino due and ran your code. With python3, the code behaves the same as you report. Different behavior in python2. This is strange. In general, your code is imho not a...

ghp

Hello, you should consider to add a 'universal database administration tool' to your toolbox. Handy to look into data, execute some statements without the need to write code for each and any sql. There are lots of them around, see https://en.wikipedia.org/wiki/Comparison_of_database_tools My favorit...

ghp

Hello, some time ago I did some investigation on how precise it is to measure short pulses of 10ms with python and compared this with a microcontroller. Most probably, these results can be interpreted 'the other way round' to estimate accuracy of pulse generation. See chart in http://heppg.de/ikg/wo...

ghp

Hello, will you control servo (pwm, 20ms cycle, pwm controlled) or solenoids with your machine ? What about 7*24 h operation ? From time to time you will loose power... And there is need for maintenance, updating os which is cpu intensive. My first ideas have been to control the hardware by an ardui...

ghp

the noob-to-nerd-page is (drum fill) http://www.python-course.eu/lambda.php

ghp

Hello, could be that your file is empty or not to be allowed to be read? Try out: - stop all code, and inspect the file. 'cat TheGameData.txt' should show the content. - If no data are in the file, take a text editor (leafpad, vi, whatever you use) and write some lines of text into this file. permis...

ghp

Sockets do not have a record structure, it is a simple sequence of bytes. Even if you send something like packets, the read operation can give you single bytes up to byte sequences from consequtive send operations. So make the data readable (ascii encoded), which is generally a good idea when you co...

Search found 1516 matches

Re: Strange errors

Re: python for mq-135 sensor

Re: Raspberry Pi and FS1000A transmitter

Re: Multithreading GPIO

Re: Error: Microsoft Visual C++ 10.0 is required (vcvarsall.

Re: GPIO pull down difference with RpI 2

Re: GPIO pin will not hold its output value

Re: pt100+max6675

Re: Raspian CPU monitor?

Re: Inaccurate timing under load - give prio?

Re: Raspian CPU monitor?

Re: Arduino to Pi with python

Re: raspberry pi weather station multiple spins

Re: Project teamwork with Python

Re: Very strange behavior (time.strftime() kills main thread

Re: Very strange behavior (time.strftime() kills main thread

Re: code

Re: Correct way to download and install modules into Python?

Re: Very strange behavior (time.strftime() kills main thread

Re: need help... Placing a function outcome into a mysql ent

Re: Newbie to Raspberry Pi 2 and Python needs your advice

Re: Newbie to Raspberry Pi 2 and Python needs your advice

Re: NOOB

Re: Problems with File input/output

Re: reading from a socket in python