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by henkoegema
Tue Feb 27, 2018 10:05 am
Forum: Mathematica
Topic: Plot a circle.
Replies: 9
Views: 12787

Re: Plot a circle.

My problem in learning Mathematic is not the maths (I'm fairly competent in maths), but finding a suitable goal to work to. I bought Schaum's outline on Mathematica, but got bored doing exercise after exercise. Alan. I didn't know about the book Schaum's outline on Mathematica. Thanks for mentionin...
by henkoegema
Mon Feb 26, 2018 8:22 pm
Forum: Mathematica
Topic: Plot a circle.
Replies: 9
Views: 12787

Re: Plot a circle.

jardino wrote:
Mon Feb 26, 2018 8:16 pm
My pleasure.

I'm not a total beginner, but am still dipping my toes in the water.

Alan.
I'm trying to do the same.
It's nearly 50 years ago I was a math teacher.
Have forgotten a lot. So I'm refreshing my (old) brains. :lol:
by henkoegema
Mon Feb 26, 2018 4:21 pm
Forum: Mathematica
Topic: Plot a circle.
Replies: 9
Views: 12787

Re: Plot a circle.

Thanks very much Alan. For your solution and for your tip :)
That's what I was looking for.
I'm a total beginner.( not in mathematics, but in Mathematica)
by henkoegema
Fri Feb 23, 2018 3:44 pm
Forum: Mathematica
Topic: Plot a circle.
Replies: 9
Views: 12787

Plot a circle.

Can somebody tell me how to plot a circle with formula x^2 +y^2 +8x + 7 = 0 in Mathematica (on a raspberry pi3 + raspbian).
Without converting the formula to x-a)^2+(y-b)^2=r^2.

I'm looking for something like: Plot[x^2 +y^2 +8x + 7 = 0, ...??.....].

Is this possible? :roll:
by henkoegema
Mon May 15, 2017 11:23 am
Forum: Python
Topic: run python as sudo ??
Replies: 1
Views: 827

run python as sudo ??

OS: Raspbian Jessie Device: RPI-0-W On this site: http://www.meccanismocomplesso.org/en/picamera-pir-movement-detector-un-sistema-di-sorveglianza/ is written: If you want to run programs in Python using the GPIO pins, remember to do it as sudo. My RPI-0-W is running 2 programs which I have put in my...
by henkoegema
Thu May 11, 2017 1:05 pm
Forum: Troubleshooting
Topic: Motion sensor with RFI/EMI (?)
Replies: 3
Views: 830

Motion sensor with RFI/EMI (?)

I have a raspberrypi-0-W with Raspbian(Jessie) Connected to the pi is a PIR (motion) sensor. Motion is detected by a python program using interrupts. When the sensor detects motion, it sends a signal via WiFi to a receiver which gives a visible and audio signal. That all works well on a breadboard. ...
by henkoegema
Sat Apr 22, 2017 3:54 pm
Forum: General discussion
Topic: sd card in Raspberry pi Zero-W ?
Replies: 2
Views: 667

sd card in Raspberry pi Zero-W ?

Can a sd card from a Raspberry Pi 2 be swapped into a Raspberry PI Zero-W ?
by henkoegema
Thu Apr 20, 2017 9:06 am
Forum: Python
Topic: Python and C++
Replies: 9
Views: 1487

Re: Python and C++

paddyg wrote:the standard arduino

Code: Select all

bool dmpReady;
setup() {
  dmpReady = false;
}
loop() {
  dmpReady = !dmpReady;
}
in python is

Code: Select all

dmpReady = False
while True:
  dmpReady = not dmpReady
Thanks, I got it working ! :D
by henkoegema
Wed Apr 19, 2017 7:33 pm
Forum: Python
Topic: Python and C++
Replies: 9
Views: 1487

Re: Python and C++

For an Arduino project I made a C++ file like this: void setup() display a fixed text on a 20x4 LCD display void main() detect motion from a sensor How do I go forward to do the same in Python (for Raspberry pi) ? So, the text on the display should only be setup once. The text doesn't change. The m...
by henkoegema
Wed Apr 19, 2017 6:28 pm
Forum: Python
Topic: NameError: name 'GPIO' is not defined
Replies: 3
Views: 5634

NameError: name 'GPIO' is not defined

# http://www.rototron.info/using-a-motion-detector-on-raspberry-pi/ # Set up input pin GPIO.setup(21, GPIO.IN, pull_up_down=GPIO.PUD_DOWN) # Set up LED output GPIO.setup(20, GPIO.OUT) # Callback function to run when motion detected def motionSensor(channel): lcd.clear() GPIO.output(20, GPIO.LOW) if...
by henkoegema
Wed Apr 19, 2017 3:04 pm
Forum: Python
Topic: Python and C++
Replies: 9
Views: 1487

Python and C++

For an Arduino project I made a C++ file like this: void setup() display a fixed text on a 20x4 LCD display void main() detect motion from a sensor How do I go forward to do the same in Python (for Raspberry pi) ? So, the text on the display should only be setup once. The text doesn't change. The mo...
by henkoegema
Thu Apr 09, 2015 2:46 pm
Forum: Troubleshooting
Topic: Time not correct
Replies: 1
Views: 354

Time not correct

I'm using a RaspberryPi2 + Wheezy I've set my timezome via :sudo raspi-config to Europe/Amsterdam When I print the command date, I get: [email protected] ~ $ date do apr 9 10:41:34 CEST 2015 CEST is the correct timezone, but.......the time is 6 hours behind the real time. ( 16 :41:34 and not 10 :41:34...
by henkoegema
Thu Oct 17, 2013 4:07 pm
Forum: Networking and servers
Topic: Send e-mails from the command line
Replies: 8
Views: 11190

Re: Send e-mails from the command line

I tried: http://c-mobberley.com/wordpress/index.php/2013/05/11/raspberry-pi-enabling-sending-emails-with-postfix/ http://iqjar.com/jar/sending-emails-from-the-raspberry-pi/ http://www.simplehelp.net/2008/12/01/how-to-send-email-from-the-linux-command-line/ http://rpi.tnet.com/project/faqs/smtp (qui...

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