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by Ferdinand
Tue Jun 27, 2017 10:04 am
Forum: General discussion
Topic: how to trigger raspi by the doorbell
Replies: 27
Views: 6442

Re: how to trigger raspi by the doorbell

You can measure the current or voltage of the doorbell. Measure the voltage accross the doorbell, use diodes to rectify it and use an optocoupler 4N33 to activate a gpio pin. If you press the doorbell to voltage is 0 v. If the doorbell is released the voltage is x V dc or ac. A current sensor/resist...
by Ferdinand
Tue Jun 27, 2017 8:39 am
Forum: General discussion
Topic: how to trigger raspi by the doorbell
Replies: 27
Views: 6442

Re: how to trigger raspi by the doorbell

Hi komarek, You can use or make a wireless doorbell by using an arduino and 2x hc12. One for the arduino and one for the rpi. You can buy a wireless doorbell set and modify/connect the receiver with a gpio pin. A de scription is available in the cloud. Use google to find it. See http://thejumps.co.u...
by Ferdinand
Sat Jun 24, 2017 3:11 pm
Forum: Other projects
Topic: Motorcycle ECU replacement
Replies: 6
Views: 2496

Re: Motorcycle ECU replacement

Hi Samski,

Due to latency a rpi is less suited for controlling a motorcycle ECU. It is better to use a micro controller thus without operating system. An ECU (micro controller) is an accurate timing device and has no latency.

Be carefull it is very dangerous what you are doing!
by Ferdinand
Thu Jun 22, 2017 2:34 pm
Forum: General programming discussion
Topic: start script on startup
Replies: 14
Views: 5711

Re: start script on startup

Try this:
python /home/pi/solar.py
or
python solar.py
by Ferdinand
Sat Jun 10, 2017 1:41 pm
Forum: Automation, sensing and robotics
Topic: Best ADC for 5v pressure sensor
Replies: 10
Views: 6683

Re: Best ADC for 5v pressure sensor

Hi cscuilla, This article explains how to connect a potentiometer, in your case a pressure sensor, and interfacing to your pi. http://www.python-exemplary.com/index_en.php?inhalt_links=navigation_en.inc.php&inhalt_mitte=raspi/en/adc.inc.php To prevent weird readings Input AIN0 and AIN1 are internall...
by Ferdinand
Fri Jun 09, 2017 7:42 am
Forum: Automation, sensing and robotics
Topic: Best ADC for 5v pressure sensor
Replies: 10
Views: 6683

Re: Best ADC for 5v pressure sensor

Method one: Remember the pressure sensor must be fed by a clean 5 V linear power supply. If you are using voltage drop devices, like a diode, then you can not handle the the full range of the sensor. Method two: You may use a resistor divider (potentiometer) for the output of the sensor and run the ...
by Ferdinand
Thu Jun 08, 2017 8:41 pm
Forum: Automation, sensing and robotics
Topic: Best ADC for 5v pressure sensor
Replies: 10
Views: 6683

Re: Best ADC for 5v pressure sensor

Or this level shifter from adafruit:
https://www.adafruit.com/product/757

Don't forget the most important: Software!

Do you have a (python) module driver for your ads1115?

Before you are buying parts make a drawing!!! And post it here.
by Ferdinand
Thu Jun 08, 2017 7:51 pm
Forum: Automation, sensing and robotics
Topic: Best ADC for 5v pressure sensor
Replies: 10
Views: 6683

Re: Best ADC for 5v pressure sensor

You do need a level shifter to protect your pi (3.3 V) because your adc runs on a 5 V. Otherwise you will fry your pi.

For more info read this:
https://nathan.chantrell.net/20120610/r ... nt-voltage
by Ferdinand
Wed Jun 07, 2017 4:21 pm
Forum: Automation, sensing and robotics
Topic: Best ADC for 5v pressure sensor
Replies: 10
Views: 6683

Re: Best ADC for 5v pressure sensor

Hi cscuilla, Did you follow this link? https://raspberrypi.stackexchange.com/questions/54155/connect-a-pressure-sensor-with-raspberry-pi-2 You will need an ad converter. The output range of the your sensor is 0.5 ~ 4.5 V. Check of your adc can handle this input range. You need a level shifter becaus...
by Ferdinand
Sun Apr 16, 2017 8:06 am
Forum: Nederlands
Topic: thermostaat onder Python
Replies: 4
Views: 1966

Re: thermostaat onder Python

Hallo beertje53, Ik neem aan dat je de ds18b20 als temperatuur sensor gebruikt. In jouw vorige post gaf je aan dat je de temp kan uitlezen. Dus dat werkt! Nu het volgende blok. #!/usr/bin/python import signal import sys import os import time def signal_handler(signal,frame): print "\n\r\n\nYou press...
by Ferdinand
Sat Apr 15, 2017 8:38 pm
Forum: Nederlands
Topic: thermostaat onder Python
Replies: 4
Views: 1966

Re: thermostaat onder Python

Hallo beertje53, Voordat je een programma gaat schrijven moet je eerst beschrijven wat moet een programma moet regelen. Het klink eenvoudig maar de praktijk is toch wel wat lastiger. Je moet een programma in blokken ofwel functies gaat opdelen. Je hebt de volgende blokken: - wat wil je regelen, een ...
by Ferdinand
Sat Mar 25, 2017 4:35 pm
Forum: Beginners
Topic: I had to add two lines to a file but can't save.
Replies: 15
Views: 2067

Re: I had to add two lines to a file but can't save.

Hi Sparks135,

Here is a links to a vi manual https://www.cs.colostate.edu/helpdocs/vi.html
by Ferdinand
Mon Feb 20, 2017 7:49 pm
Forum: Python
Topic: GPIO.add_event_detect Madness - double presses detected
Replies: 11
Views: 2131

Re: GPIO.add_event_detect Madness - double presses detected

Hi MD500_Pilot ,

Just connect a switch between gpio2 (i2c clk) and ground and connect a capacitor between gpio2 and ground. That's all.
Test this circuit and what do you obverse?

Success..
by Ferdinand
Mon Feb 20, 2017 5:36 pm
Forum: Python
Topic: GPIO.add_event_detect Madness - double presses detected
Replies: 11
Views: 2131

Re: GPIO.add_event_detect Madness - double presses detected

Hi MD500_Pilot,

You have to follow coder-tronics.

Success
by Ferdinand
Mon Feb 20, 2017 5:38 am
Forum: Python
Topic: GPIO.add_event_detect Madness - double presses detected
Replies: 11
Views: 2131

Re: GPIO.add_event_detect Madness - double presses detected

Hi MD500_Pilot,

Remove R9 and R8 is 0 k ohm (R8 is a wire). The rest is ok.


Instead of a RC circuit you may use this:
http://www.ganssle.com/debouncing-pt2.htm
The output of this diagram 'To CPU' is in your case GPIO2.

Success.
by Ferdinand
Sun Feb 19, 2017 9:54 pm
Forum: Python
Topic: GPIO.add_event_detect Madness - double presses detected
Replies: 11
Views: 2131

Re: GPIO.add_event_detect Madness - double presses detected

Hi MD500_Pilot, The gpio circuitry is designed for 3.3 V and is not 5 V tolerant. So it is better to use a buffer ic / mosfet or transistor to protect your gpio stage. Measure the voltage on gpio2. If the switch S1 is not pressed you measure a voltage of ~3.3 V if you press the switch you measure a ...
by Ferdinand
Sun Feb 19, 2017 12:08 pm
Forum: Python
Topic: GPIO.add_event_detect Madness - double presses detected
Replies: 11
Views: 2131

Re: GPIO.add_event_detect Madness - double presses detected

Hi MD500_Pilot, Some remarks: 1) Led D7 will never lit because both sides of the led are at groundlevel. 2) use 74hct buffer/drivers for driving the relays. According to your schematic one pin of your relais is connected to the 5 V rail and the other pin is conncected to a gpio pin. It could fry you...
by Ferdinand
Sat Feb 18, 2017 4:29 pm
Forum: Nederlands
Topic: raspberry en de slimme meter
Replies: 7
Views: 7603

Re: raspberry en de slimme meter

Hallo harsat, Je kunt een kabel maken of er een kopen bij https://sossolutions.nl/slimme-meter-kabel . Sossolutions verkoopt een kabel die rs232 signalen naar usb. Je moet dan zelf uitzoeken of deze kabel aan jouw wensen voldoet. Ik heb software gemaakt die je mag gebruiken/wijzigen enz. Per dag wor...
by Ferdinand
Sat Feb 18, 2017 12:29 pm
Forum: The MagPi
Topic: Using a Hall effect sensor with RPi
Replies: 4
Views: 4492

Re: Using a Hall effect sensor with RPi

Hi arclite,

Are you looking for this article?

http://www.raspberrypi-spy.co.uk/2015/0 ... pberry-pi/
by Ferdinand
Fri Feb 17, 2017 8:47 pm
Forum: The MagPi
Topic: Using a Hall effect sensor with RPi
Replies: 4
Views: 4492

Re: Using a Hall effect sensor with RPi

Hi arclite, I rewrote the original hall.py code a little bit. Connect the output of the open collector of the hall sensor to GPIO 17 and use a pullup resistor of ~2.7 k ohm to 3.3 v. If the south pole passes the hall sensor it will turn the output on. This py script counts the passes of the magnet o...
by Ferdinand
Wed Feb 08, 2017 9:56 am
Forum: Beginners
Topic: Measuring strain on a bike frame
Replies: 5
Views: 2020

Re: Measuring strain on a bike frame

Hi smiles123, Very interesting project! There are many sensors available, see for an overview this link: https://www.electricbike.com/torque-sensors/ for strain gauges this link: https://www.hbm.com/nl/0014/rekstroken The sensor (in one of the branches of a wheatstone bridge) converts a torque/strai...
by Ferdinand
Thu Feb 02, 2017 4:48 pm
Forum: Python
Topic: Battery level indication
Replies: 8
Views: 5189

Re: Battery level indication

Hi El Fred, Look for 'Running the Example Code' in the given link. We’ve included two example programs for the Arduino microcontroller to show you how to use the Coulomb Counter. If you’re not using an Arduino, the example code is very straightforward and should be easily adapted to other microcontr...
by Ferdinand
Thu Feb 02, 2017 3:02 pm
Forum: Python
Topic: Battery level indication
Replies: 8
Views: 5189

Re: Battery level indication

Hi El Fred,

Search for 'coulomb counter'. It is a micro controlled counter used in ebikes, ecar batteries a.s.o.
Perhaps you can use it.

Follow this link for a simple circuit. It is just an idea.
https://learn.sparkfun.com/tutorials/lt ... okup-guide

Success with your project
by Ferdinand
Sat Jan 14, 2017 10:25 am
Forum: Automation, sensing and robotics
Topic: Controlling solenoid valves with Pi not working
Replies: 18
Views: 4466

Re: Controlling solenoid valves with Pi not working

Hi tap,

Use a voltmeter to measure the voltage across ce of your tip120. It must be around 2 V.
It is better to use a n channel mosfet.
See this 'article': http://sensitiveresearch.com/elec/DoNot ... x.html#hfe

Success with your project!

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