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by ElEscalador
Mon Dec 09, 2019 1:27 pm
Forum: Automation, sensing and robotics
Topic: Thermostat
Replies: 2
Views: 50

Re: Thermostat

Your question is not clear on details. You have a thermostat or want to make one? In any case, the device appears to have a built in thermostat... somewhere, this thermostat acts as a simple switch. Use the Pi to close a relay in parallel with this switch. Alternatively, leave that thermostat set to...
by ElEscalador
Mon Dec 09, 2019 12:56 pm
Forum: Beginners
Topic: Position sensing
Replies: 3
Views: 91

Re: Position sensing

Historically you use an inertial measurement unit (IMU) that usually includes a 3 axis accelerometer, gyroscope, and sometimes magnetometer. The provide you linear acceleration in 3 vectors, angular rate of rotation and you can do some maths and integrate to get position changes. I've recently found...
by ElEscalador
Sun Dec 08, 2019 3:33 pm
Forum: C/C++
Topic: From python to C/C++
Replies: 5
Views: 162

Re: From python to C/C++

Code: Select all

#include <iostream>

using namespace std;

int get_input()
{
   int x;
   cin>>x;
   return x;
}

int main()
{
   int y = get_input();
   for(int q = 0; q<input; q++)
   {
      //do stuff here
   }
   return 0;
}
by ElEscalador
Thu Dec 05, 2019 12:41 pm
Forum: Troubleshooting
Topic: Use ttyS0, serial0 or AMA0?
Replies: 3
Views: 84

Re: Use ttyS0, serial0 or AMA0?

Before adding a device, try testing the port with a bit of your own code by jumping the tx and rx pin. Write a few bytes and master receiving them. When you've done that, question of which port is irrelevant and you can focus on the gps and interfacing with it. If you are using a distro other than r...
by ElEscalador
Mon Dec 02, 2019 1:04 pm
Forum: HATs and other add-ons
Topic: Magnetometer incorrect
Replies: 2
Views: 98

Re: Magnetometer incorrect

Magnetometers are tricky because of how very sensitive they are to surrounding magnetic fields and even the angle they are sitting at for a given reading. If there are magnetic fields on the robot (or whatever its mounted on/in) that can often be calibrated out... even doing so, my calibrated magnet...
by ElEscalador
Thu Nov 28, 2019 8:06 pm
Forum: Troubleshooting
Topic: Serial port won't open after using minicom
Replies: 4
Views: 102

Re: Serial port won't open after using minicom

I've had that problem. I think it was solved by closing minicom with the ctrl-a, then z or menu, then x for the official "close minicom" dance instead of just closing the window. Or maybe it was the other thing where closing the window worked. Been a while. But yeah, something in minicom hangs onto ...
by ElEscalador
Wed Nov 13, 2019 12:25 pm
Forum: Off topic discussion
Topic: What dictates the accuracy of a gps module?
Replies: 8
Views: 556

Re: What dictates the accuracy of a gps module?

Largely - changing atmospheric conditions that a lone receiver cannot correct for. With two receivers and some math, it is possible to get 1-2cm accuracy. See RTK GPS.
by ElEscalador
Sat Oct 05, 2019 12:21 am
Forum: Troubleshooting
Topic: Raspberry Pi 3+ Communication via UART RX TX GPIO Pins
Replies: 8
Views: 461

Re: Raspberry Pi 3+ Communication via UART RX TX GPIO Pins

Aside from checking that you are on the correct pins, I almost always test my serial uart with a local loopback (jumper from tx to rx) and make sure that's working before I introduce an external device.
by ElEscalador
Sat Oct 05, 2019 12:16 am
Forum: Troubleshooting
Topic: Raspberry Pi 3+ Communication via UART RX TX GPIO Pins
Replies: 8
Views: 461

Re: Raspberry Pi 3+ Communication via UART RX TX GPIO Pins

The gpio tx/rx pins are 14 and 15... unless I've missed some changes.
by ElEscalador
Fri Oct 04, 2019 2:01 pm
Forum: C/C++
Topic: Where can I begin learning C/C++?
Replies: 72
Views: 5824

Re: Where can I begin learning C/C++?

learncpp.com Buckys c++ tutorials on youtube It's technically a bit dated but for a noob I still highly recommend "C++ for dummies" As far as IDEs, I really don't like geany and find codeblocks much friendlier. I haven't run it on a Pi 4, but if you have problems with it randomly crashing PM me and ...
by ElEscalador
Mon Sep 30, 2019 5:48 pm
Forum: Python
Topic: Creating fake voltage for unit tests
Replies: 2
Views: 234

Re: Creating fake voltage for unit tests

Sure, depending on what you're doing you can write a program to control a pins output and monitor the same pin with another program, or you can use two separate pins and some circuit and jumper.
by ElEscalador
Wed Sep 18, 2019 6:26 pm
Forum: Automation, sensing and robotics
Topic: Liquid volume sensor in a tank
Replies: 10
Views: 1274

Re: Liquid volume sensor in a tank

I'd wager any HC-SR04 cheap ultrasonic would work for you - tutorials available everywhere. Laser distance...maybe? I haven't tried it but i'd be concerned about the liquid absorbing the light...although it's milk, not murky water. I think ultrasonic will be cheaper and easier anyway. Both are much ...
by ElEscalador
Wed Sep 18, 2019 12:42 pm
Forum: Automation, sensing and robotics
Topic: Liquid volume sensor in a tank
Replies: 10
Views: 1274

Re: Liquid volume sensor in a tank

The most accurate tank level sensors used in my industry (where we have tons of tanks full of stuffs) measure differential pressure - But Andy is correct that it does not provide a volume until you know the shape and dimensions of the tank and do the math to calculate. Straightforward if the tank is...
by ElEscalador
Thu Sep 12, 2019 12:01 am
Forum: Beginners
Topic: Relay - can it be used in reverse (signal microcontroller) ?
Replies: 14
Views: 847

Re: Relay - can it be used in reverse (signal microcontroller) ?

You could certainly use a relay with a 100vac coil like this one https://amzn.to/2NVr0RV Unless you're in Britain, or Europe, or other places with 230V AC Very true - my bad. I can't help it - as an American, I was raised that we're center of the universe. Also our new thing is to refuse to correct...
by ElEscalador
Wed Sep 11, 2019 12:25 pm
Forum: Beginners
Topic: Relay - can it be used in reverse (signal microcontroller) ?
Replies: 14
Views: 847

Re: Relay - can it be used in reverse (signal microcontroller) ?

You could certainly use a relay with a 100vac coil like this one https://amzn.to/2NVr0RV and monitor the contacts as you would any switch - I do it all the time for different reasons but I also worth with and control voltages up to 480 3 phase for a living. I think the above is is on the right track...
by ElEscalador
Tue Aug 27, 2019 9:38 pm
Forum: Automation, sensing and robotics
Topic: Motor Sensing Circuit help
Replies: 5
Views: 616

Re: Motor Sensing Circuit help

If it's simple on/off, you can bias a transistor with it. I wish I could easily post a sketch. There are different types of transistors...I'll talk about an NPN - which I always thought of as "supplies a negative" when biased with a positive. Basically the input from your sensor would go to the "bas...
by ElEscalador
Sat Aug 17, 2019 12:09 pm
Forum: Beginners
Topic: IR laser and reciever
Replies: 3
Views: 688

Re: IR laser and reciever

Not sure why you'd want specifically a laser, but I would try modulating the laser output on and of with the output from the serial pin (TXing a unique identifier and whatever other information). The receiver is just an IR phototransistor as an interface to the RX pin. If the tanks send at the same ...
by ElEscalador
Thu Aug 15, 2019 11:54 am
Forum: General discussion
Topic: Using Pi for driving 100 or more electromagnets
Replies: 4
Views: 340

Re: Using Pi for driving 100 or more electromagnets

PWM is trivial on the pi (try pigpio)but there aren't 100 pins so unless some of them are going to be operated in parallel no - you cannot control 100+ without external hardware. What are you driving the magnets with? Certainly you are aware that you need some driving hardware because the PI pins ca...
by ElEscalador
Fri Jul 26, 2019 11:54 am
Forum: Automation, sensing and robotics
Topic: SLAM robot raspberry pi 4
Replies: 6
Views: 1712

Re: SLAM robot raspberry pi 4

Neato XV11 robot vacuum lidar is dirt cheap on ebay these days. Other than that...wheel encoders. They'll work on any pi. I'm not really sure what the pi4 would do for you over a pi3B (not even the 3B+) besides suck down your battery and give you headache getting all the software working that isn't ...
by ElEscalador
Sun Jul 21, 2019 3:48 pm
Forum: Beginners
Topic: Using a desktop PC for Pi development
Replies: 8
Views: 618

Re: Using a desktop PC for Pi development

Realvnc. Preinstalled at least on the last couple versions. You can leave your pi at home and program/control your robot or whatever from the space station or anywhere else with internet.
by ElEscalador
Fri Jul 05, 2019 1:56 pm
Forum: General discussion
Topic: Does the pi throttle for temperature regardless of OS?
Replies: 5
Views: 459

Re: Does the pi throttle for temperature regardless of OS?

Thanks. This made the most sense to me, but I have learned through years of troubleshooting devices that I had better not rely on anything being built or programmed in the manner that seems to make the most sense,
by ElEscalador
Thu Jul 04, 2019 9:18 pm
Forum: General discussion
Topic: Does the pi throttle for temperature regardless of OS?
Replies: 5
Views: 459

Does the pi throttle for temperature regardless of OS?

I just realized I have no idea if temp monitoring and throttling happens somewhere in firmware or if it's handled by Raspbian. Does it still throttle if running something else like lubuntu?
by ElEscalador
Wed Jul 03, 2019 2:48 pm
Forum: General discussion
Topic: Pi 5 needs only one upgrade, please
Replies: 1
Views: 263

Pi 5 needs only one upgrade, please

Fan pins. All these extras on the 3b+ and now the 4 and all I really wanted was an extra pair of pins (5v/gnd) to plug a doggone fan into without losing the ability to plug a standard 40 pin cable into my GPIO header.
[/rant]
by ElEscalador
Mon Jul 01, 2019 1:52 pm
Forum: Other projects
Topic: non programmer needs to build an all inclusive pool controller
Replies: 15
Views: 1100

Re: non programmer needs to build an all inclusive pool controller

Start with identifying what parts you need to control. I'm going to guess...pump..maybe heater? No idea what else. Those would most commonly be turned on and off, rather than needing varying signals to control. This would most commonly be done with relays. So you need to learn how to control a relay...
by ElEscalador
Thu May 23, 2019 12:02 pm
Forum: Beginners
Topic: wifi remote access to usb Camera within c++ application
Replies: 1
Views: 104

Re: wifi remote access to usb Camera within c++ application

What does the program need to be able to do with the images? I know there are better, more elegant, more "correct" ways but the easiest thing I found was to use a system("command line command here") call to take a pic and then another to email the pic/video to myself and push it to dropbox and//or e...

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