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by blimpyway
Mon Dec 09, 2019 12:23 pm
Forum: Python
Topic: Picamera offline installation
Replies: 2
Views: 116

Re: Picamera offline installation

Smart phone with 3/4G + hotspot?

Get/borrow another PI with internet access, do there the installation, (multiply the SD if more than one) then use the SD(s) on the remote Pi(es)?
by blimpyway
Sat Dec 07, 2019 12:02 am
Forum: Other projects
Topic: Water temperature and pump control for pond - how?
Replies: 2
Views: 113

Re: Water temperature and pump control for pond - how?

If you look for reliable, use an arduino with a temperature sensor and a pair of relay module.

You can make it report state (temperature, relay states) later by serial to a Pi or ESP8266, just keeping the control loop on a simpler device makes the whole assembly much more reliable.
by blimpyway
Thu Nov 28, 2019 6:46 am
Forum: Automation, sensing and robotics
Topic: HX711 and weight cell don't work
Replies: 7
Views: 195

Re: HX711 and weight cell don't work

The load cell in your image should be a full wheatstone bridge. From colors my guess the connection should be: red -> E+ black -> E- white, yellow -> to A+ and A-, order irrelevant (you switch these two to get negative or positive readings) But best way to be sure is to measure the resistance betwee...
by blimpyway
Sat Nov 16, 2019 10:53 pm
Forum: Automation, sensing and robotics
Topic: How to turn on Multiple TVs using a raspberry Pi?
Replies: 4
Views: 225

Re: How to turn on Multiple TVs using a raspberry Pi?

Wifi, 45 x (esp-01's + ir transmitter diodes).

And a Pi to talk to them all.
by blimpyway
Wed Nov 13, 2019 10:38 pm
Forum: Python
Topic: What is pyserial and how to use it?
Replies: 3
Views: 134

Re: What is pyserial and how to use it?

From mentioning "serial monitor" I assume you use an Arduino which reads the PWM and then prints a value on serial line. If not (you want to read PWM signal directly with a raspberry pi) then pyserial will not be helpful If yes then you should install pyserial module $ sudo pip install pyserial Then...
by blimpyway
Thu Nov 07, 2019 12:52 pm
Forum: Python
Topic: RAM keeps decreasing
Replies: 9
Views: 1142

Re: RAM keeps decreasing

The "free" value decreasing doesn't necessarily means there is less memory available. It could be used for buffers/cache, which is normal when moving many large files. Look at "available" memory column (last one) instead pi@pizerow:~ $ free total used free shared buff/cache available Mem: 376224 554...
by blimpyway
Wed Nov 06, 2019 8:39 pm
Forum: Python
Topic: RAM keeps decreasing
Replies: 9
Views: 1142

Re: RAM keeps decreasing

I don't know why it uses all the RAM. I suspect more the repeated mount/unmount of the SD card. I don't understand what GPIO output triggers and how the SD card gets re-mounted - your script only unmounts it. ---------------- Regarding output of top - I think it is meaningful to run top while your p...
by blimpyway
Wed Nov 06, 2019 9:15 am
Forum: Other projects
Topic: Xmas light Project
Replies: 1
Views: 550

Re: Xmas light Project

If you-re talking about ws2811/ws2812/etc strips then you should be able to control hundreds of LEDs on a single line.

You need to identify the led types (there are several protocols out there) and then search for the right software library/instructions needed to communicate with them
by blimpyway
Wed Nov 06, 2019 9:01 am
Forum: Automation, sensing and robotics
Topic: Best way to send signal om 2.4Ghz RF
Replies: 8
Views: 1111

Re: Best way to send signal om 2.4Ghz RF

If the transmitter is a remote control, with push buttons, there is a great chance you can make the Pi "push" these buttons via GPIO.
by blimpyway
Wed Nov 06, 2019 8:38 am
Forum: Automation, sensing and robotics
Topic: Using Raspberry to receive data from Ti Launchpad (cc1350)
Replies: 2
Views: 642

Re: Using Raspberry to receive data from Ti Launchpad (cc1350)

From http://www.ti.com/product/CC1350 it seems it is just an ARM M3 controller with wireless capabilities.
So you could use I2C, UART, or even bluetooth or wifi to communicate with Pi and not only
by blimpyway
Wed Nov 06, 2019 8:20 am
Forum: Python
Topic: RAM keeps decreasing
Replies: 9
Views: 1142

Re: RAM keeps decreasing

1. What does your program prints? Only once the print("Total duration: " + str(END-START)) or several times? 2. Avoid using pass in while tests... use time.sleep() instead. That slows down the loop on filesystem, allowing the interpreter and OS to.. "breathe". e.g. while(not path.exists('/media/pi/S...
by blimpyway
Mon Nov 04, 2019 8:11 am
Forum: Other projects
Topic: Power bank for the raspberry pi 4
Replies: 7
Views: 1005

Re: Power bank for the raspberry pi 4

The powerbank page says it can deliver 18W power (~3500mA) Although this is smaller than 5000mA (by adding peak consumption for both Pi4 and screen), there are high chances it would work. These peak figures do not reflect normal consumption, e.g. normal power usage of Pi 4 rarely exceeds 1000mA and ...
by blimpyway
Sun Nov 03, 2019 7:55 am
Forum: Other projects
Topic: smooth analog voltage from 0 to 12V
Replies: 10
Views: 1249

Re: smooth analog voltage from 0 to 12V

8 bit /channel. Pretty much the same range as any RGB picture/video you see on a computer screen. Also: - human eye / visual cortex has problems distinguishing more than 30 levels of brightness between black and white. - sun's full light intensity is orders of magnitude more powerful than a strip of...
by blimpyway
Fri Nov 01, 2019 9:11 pm
Forum: Other projects
Topic: smooth analog voltage from 0 to 12V
Replies: 10
Views: 1249

Re: smooth analog voltage from 0 to 12V

simple PWM (through a power transistor/mosfet per channel) should be sufficient to change led colour/intensity, no need for actual voltage control.

However I'd use an addressable led strip (price is not much greater) and get rid of 3 channel high power circuitry.
by blimpyway
Fri Nov 01, 2019 8:26 pm
Forum: Automation, sensing and robotics
Topic: Can I use an outdoor mains PIR with a Pi?
Replies: 5
Views: 454

Re: Can I use an outdoor mains PIR with a Pi?

most likely not these modules are just the sensor with its circuit. The rating is given by the case and gaskets/glue/silicone used to close it air/dust/water tight. If you need an official weatherproof rating is one problem, if you need just to weatherproof the sensor is a different one. PS if one f...
by blimpyway
Fri Nov 01, 2019 8:20 pm
Forum: Automation, sensing and robotics
Topic: Interrupts for motor control
Replies: 8
Views: 758

Re: Interrupts for motor control

I would use an "outside" arduino (with more reliable interrupts than a linux environment) to count the interrupts and send the results via serial line.

Also if you share the code there are more chances someone will notice why it behaves this way.
by blimpyway
Fri Nov 01, 2019 6:30 pm
Forum: Automation, sensing and robotics
Topic: Can I use an outdoor mains PIR with a Pi?
Replies: 5
Views: 454

Re: Can I use an outdoor mains PIR with a Pi?

Search for Arduino mini PIR sensor modules. These should work from 2.7 to 12.0 volts, so they-re ok with Pi's 3.3V gpio
by blimpyway
Fri Nov 01, 2019 9:06 am
Forum: Other projects
Topic: smooth analog voltage from 0 to 12V
Replies: 10
Views: 1249

Re: smooth analog voltage from 0 to 12V

RGB strips are normally addressable, they have a dedicated datalink (using a gpio pin) to set intensity for red, green, blue for each individual LED on the strip. So you shouldn't fiddle with their supply power but seek tutorials on what types of addressable strips are there and how to control them ...
by blimpyway
Fri Oct 18, 2019 5:32 pm
Forum: Automation, sensing and robotics
Topic: Can I use a PCA9685 like this?
Replies: 3
Views: 1048

Re: Can I use a PCA9685 like this?

In general it is better to search and read documentation for each specific model (of servos in this case), There should be written what it accepts and what not.
by blimpyway
Sat Oct 12, 2019 7:59 pm
Forum: Automation, sensing and robotics
Topic: Liquid volume sensor in a tank
Replies: 10
Views: 1274

Re: Liquid volume sensor in a tank

Will the sonic work through Saran Wrap? Probably yes. Worth make a simple test with the HC-SR04 in a plastic box with a thin plastic foil instead of lid, facing downwards. Avoid stretching the foil tight (like a drum membrane) , but let it loose(like a curtain). It shouldn't be much in the way of s...
by blimpyway
Sat Oct 12, 2019 7:40 pm
Forum: Python
Topic: Writing the result to the list and to a text file.
Replies: 5
Views: 672

Re: Writing the result to the list and to a text file.

...or the least pythonic

Code: Select all

#!/bin/bash
sudo iwlist wlan0 scan | grep "ESSID" > /home/pi/Desktop/pi_cam/networks.txt
by blimpyway
Thu Oct 10, 2019 7:30 am
Forum: Python
Topic: Writing to a text file in a specific line.
Replies: 10
Views: 708

Re: Writing to a text file in a specific line.

Only if these files and their formatting are already generated/used by applications out of your control makes sense to use a cryptic, specialised flat file format for structured data.

Otherwise I would take Andyroo's advice, use a standard one like json.
by blimpyway
Thu Oct 10, 2019 7:05 am
Forum: Python
Topic: Disordered list on raspberry pi and not on mac
Replies: 6
Views: 541

Re: Disordered list on raspberry pi and not on mac

for key, value in result['city_info'].items(): info_valeur.append((key,value)) print(info_valeur) info_valeur.sort() print(info_valeur) As you see below there is no implicit order on dictionary items() output. You can sort them yourself, then print values only and they will be consistently keep the...
by blimpyway
Sat Oct 05, 2019 7:39 pm
Forum: Python
Topic: ModuleNotFoundError: No module named 'cv2.cv'; 'cv2' is not a package
Replies: 1
Views: 273

Re: ModuleNotFoundError: No module named 'cv2.cv'; 'cv2' is not a package

all I can say is importing cv2.cv worked only on a pi with older opencv on python2 Newer versions, including an ubuntu laptop gave the same error. You probably need to either find same methods in other cv2 modules or find a newer example code with same functionality. $ python2 Python 2.7.13 (default...

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