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by blimpyway
Mon Jan 06, 2020 12:23 am
Forum: Automation, sensing and robotics
Topic: HC-SR04 ultrasonic distance module won't read any further than 100cm
Replies: 8
Views: 415

Re: HC-SR04 ultrasonic distance module won't read any further than 100cm

for a distance that short you should be able to probe 50 times/sec which gives a 20ms accuracy. There are few ways to make it more accurate - e.g you can use a flat reflective plate (like a gate) and measure continuously the 1.5m gap between sensor and reflector. The difference between a fixed rigid...
by blimpyway
Mon Jan 06, 2020 12:04 am
Forum: Python
Topic: Python library to get EXIF tags from camera?
Replies: 6
Views: 460

Re: Python library to get EXIF tags from camera?

you can execute exif utility and read its output.

Code: Select all

$ sudo apt-get install exif 


$ exif -m file.jpg
by blimpyway
Sun Jan 05, 2020 11:56 pm
Forum: Python
Topic: Converting this Arduino code to Python
Replies: 4
Views: 5634

Re: Converting this Arduino code to Python

You can just leave the speed sensing running on arduino (pro mini, nano) and read its serial printed values in python, either Pi or PC, laptop.
by blimpyway
Fri Dec 27, 2019 10:54 am
Forum: Python
Topic: How to synchronize data on txt files between raspberrys
Replies: 16
Views: 508

Re: How to synchronize data on txt files between raspberrys

... or just don't, use mqtt (message queue) to broadcast state updates and trace them independently on each pi.

Same thing could be use to query current state - needed when one of the PI-s boots up. Or negotiate a "master Pi" - which one is responsible with the overall state updates.
by blimpyway
Sat Dec 21, 2019 6:56 am
Forum: Other projects
Topic: Solar camera timelapses with raspberry pi zero
Replies: 2
Views: 271

Re: Solar camera timelapses with raspberry pi zero

It's good you did not mention what camera, schematics, which os versions you upgraded from or to, what software you use for this or which kernel module isn't loading.

That would make it a too simple riddle.
by blimpyway
Mon Dec 16, 2019 5:44 am
Forum: Automation, sensing and robotics
Topic: pizza vending machine
Replies: 5
Views: 341

Re: pizza vending machine

Contrary to appearances, this is not a complicated program :) Does it have any user interface? Buttons, knobs, timer, power settings? Besides, I only know PHP. But not enough to control GPIO pins of RPi. I don't know PHP but I would learn it if I'll be able to also write arm assembly code afterwards.
by blimpyway
Mon Dec 16, 2019 5:27 am
Forum: Automation, sensing and robotics
Topic: Train engine direction and number detection and reporting
Replies: 5
Views: 380

Re: Train engine direction and number detection and reporting

Assuming by "train engine number" you actually mean "a number printed on a moving train" , you can start by mounting either an outdoor webcam or a pi + camera + weatherproof case, and using motion detection start collecting footage of passing trains. See if you get usable frames - those which captur...
by blimpyway
Sun Dec 15, 2019 10:00 am
Forum: Automation, sensing and robotics
Topic: Train engine direction and number detection and reporting
Replies: 5
Views: 380

Re: Train engine direction and number detection and reporting

What train? The ones I know do not have engines, locomotives have engines.

What is the camera for?
by blimpyway
Sun Dec 15, 2019 9:44 am
Forum: Automation, sensing and robotics
Topic: pizza vending machine
Replies: 5
Views: 341

Re: pizza vending machine

The control program is written in assembly.
OMG that wasn't a joke! Why?
by blimpyway
Thu Dec 12, 2019 3:38 am
Forum: Other projects
Topic: DCF77 ntp server
Replies: 5
Views: 296

Re: DCF77 ntp server

But still nothing on "screen /dev/ttyAMA0 9600" as root. I am starting to think something is broke............ It is not broke. The screen command expects serial ascii at 9600 baud. The protocol mentioned by g4bcf says: . The output will be a pulse per second with a long pulse reperesenting a binar...
by blimpyway
Thu Dec 12, 2019 3:08 am
Forum: Automation, sensing and robotics
Topic: 433Mhz boards
Replies: 4
Views: 262

Re: 433Mhz boards

well, the first one mentions a pdf instructions doc. That should tell you what it can and can not do.

A LoRa module might be able to talk with other LoRa devices. Like smart meters.
by blimpyway
Thu Dec 12, 2019 2:13 am
Forum: Automation, sensing and robotics
Topic: installing OpenCV issues
Replies: 3
Views: 272

Re: installing OpenCV issues

if you need python3.6 with opencv 3.3 an easy way to install it packed together with lots of other stuff (numpy, scipy, scikit learn, jupyter notebooks, pandas, etc..) is berryconda.

Beware it will add almost 1.5GBytes to your SD card.
by blimpyway
Thu Dec 12, 2019 1:56 am
Forum: Automation, sensing and robotics
Topic: 433Mhz boards
Replies: 4
Views: 262

Re: 433Mhz boards

my equipments using DIO 1. What is DIO 1 ? These are apples and oranges. The second one is a LoRa communication module, accessible via serial communication. The first one... is not. The seller says there is some documentation on how to use it to communicate with other, generic 433MHz devices. I dou...
by blimpyway
Mon Dec 09, 2019 12:23 pm
Forum: Python
Topic: Picamera offline installation
Replies: 2
Views: 225

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: 3
Views: 346

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: 414

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: 333

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: 192

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: 1440

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 [email protected]:~ $ 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: 1440

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: 642

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: 1292

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: 800

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: 1440

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...

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