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by ElEscalador
Thu Oct 22, 2020 11:54 am
Forum: Python
Topic: I want to know how to use Kalman filter
Replies: 1
Views: 69

Re: I want to know how to use Kalman filter

I know you are asking in the python section, but I have this C++ example handy and maybe you have enough C++ to understand it. Or, if you are not set on writing your own you could use this already written one with ROS for whatever your application. ROS allows you to mix C++ programs with python prog...
by ElEscalador
Wed Oct 21, 2020 12:18 pm
Forum: Beginners
Topic: Can I control electric impulses with my Raspberry Pi 4?
Replies: 2
Views: 135

Re: Can I control electric impulses with my Raspberry Pi 4?

Everything Bob said but I'll add that a relay module is another option besides a transistor. Many people find them more intuitive and are more comfortable with them starting out. I like them for noobs because they make an audible click and often have an indicator light - both make troubleshooting ea...
by ElEscalador
Wed Oct 21, 2020 12:09 pm
Forum: Beginners
Topic: connceting raspberry with other devices
Replies: 1
Views: 59

Re: connceting raspberry with other devices

No. All Pis just need to connect to the same wifi access point. Then one can SSH into the rest if they are set up to allow ssh access.
by ElEscalador
Wed Oct 21, 2020 12:07 pm
Forum: Other projects
Topic: GPIO connection to existing bike sensor
Replies: 11
Views: 409

Re: GPIO connection to existing bike sensor

I would bet $5 that your sensor is a hall effect sensor rather than a reed relay. It makes a little difference in that the 2.8v you're reading probably is not truly the thing sourcing 2.8v, but rather it's a voltage from the sensor floating. (With hall effect sensors, they usually float without the ...
by ElEscalador
Wed Oct 21, 2020 11:54 am
Forum: Beginners
Topic: Advise Needed for First Robotics Project
Replies: 5
Views: 142

Re: Advise Needed for First Robotics Project

Very nice first project, even if it's not performing quite as you'd hoped. I'm afraid that Zero is going to continue to disappoint. I know space is a concern for you but I wouldn't consider less than a 2B for a robot. Also I don't think web page interfaces are known for their performance - I could b...
by ElEscalador
Mon Oct 19, 2020 12:35 pm
Forum: Beginners
Topic: Image processing using Raspberry Pi
Replies: 8
Views: 218

Re: Image processing using Raspberry Pi

You don't need a Raspberry Pi, but if that's what you choose A 3B should do the trick - although a 4 will have a much faster frame rate. OpenCV takes a little learning but once you have a few basics what you describe is pretty easy. You'll find no shortage of python tutorials with OpenCV. A lot less...
by ElEscalador
Thu Oct 15, 2020 3:41 pm
Forum: Automation, sensing and robotics
Topic: Autonomous Boat, course problem with PID loops.
Replies: 12
Views: 542

Re: Autonomous Boat, course problem with PID loops.

We widely use Kalman filters in automation to fuse several sensors (because it's rare that one sensor does everything you need reliably) and also to weed out wild and errant signals.
by ElEscalador
Thu Oct 15, 2020 3:29 pm
Forum: General discussion
Topic: 100mA supply from PWM pin
Replies: 14
Views: 361

Re: 100mA supply from PWM pin

Sounds like a single transistor should work and a whole chip would be a bit overkill.. 2n3904 perhaps.
by ElEscalador
Fri Oct 09, 2020 11:34 am
Forum: General discussion
Topic: GPIO Detect from external signal
Replies: 19
Views: 580

Re: GPIO Detect from external signal

If you can get to the LED leads it will be possible to either directly or via a transistor (acting as an amplifier) read that with a Pi. An simple OpenCV project should be able to do it as well just by looking at it..Although it might be a little tricky to do constantly (while wearing the strap duri...
by ElEscalador
Thu Sep 03, 2020 9:56 pm
Forum: Troubleshooting
Topic: GPIO board and motor not working
Replies: 3
Views: 124

Re: GPIO board and motor not working

Not nearly enough information for us to be able to help. How is it connected to the pi? How is it powered? What code are you trying to run?
by ElEscalador
Thu Sep 03, 2020 9:37 pm
Forum: Automation, sensing and robotics
Topic: Motor Driver Board should stop motor when torque > limit
Replies: 4
Views: 314

Re: Motor Driver Board should stop motor when torque > limit

You could certainly monitor current (will need an analog to digital converter), although simply putting end switches at the stop-points would be much easier. Another option would be to add an encoder and track position, although this usually requires at least one "home" end switch anyway. End switch...
by ElEscalador
Sat Jul 04, 2020 3:13 pm
Forum: General discussion
Topic: in need to help with passing radar module signal to rpi
Replies: 8
Views: 548

Re: in need to help with passing radar module signal to rpi

hi, i did try to measure using a voltmeter and i did get some reading from the component. may i ask when you said 'pullup resistor will need to be pulling low', does it mean that i have to connect a resistor to a breadboard with the 3.3v power supply? i tried looking up at pull up resistors circuit...
by ElEscalador
Fri Jun 26, 2020 1:12 pm
Forum: Automation, sensing and robotics
Topic: Choice of Pi to run RC boat with GPS, Motor control etc
Replies: 1
Views: 209

Re: Choice of Pi to run RC boat with GPS, Motor control etc

It may be doable with a pi zero - that will get you the least battery drain...developing on it is painfully slow, so I usually write and test on a 3B and then move code when all is working. If you were to use any other PI on board, I always recommend (and use myself) a 3B (Not 3B+) for what I think ...
by ElEscalador
Wed Jun 24, 2020 3:21 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: C++ library to control GPIO for Raspberry Pi 4
Replies: 7
Views: 604

Re: C++ library to control GPIO for Raspberry Pi 4

Wiringpi is deprecated. I really like pigpio... You can read a whole bank at a time and it returns a uint32_t.
by ElEscalador
Tue Jun 23, 2020 1:09 pm
Forum: Troubleshooting
Topic: Using IR sensor as a triggering event
Replies: 10
Views: 328

Re: Using IR sensor as a triggering event

Try reposting your code in code tags. We can't see any indents this way - those are critical in python for where loops etc start/stop.
by ElEscalador
Tue Jun 23, 2020 1:05 pm
Forum: Beginners
Topic: Monitoring A/C redundancy box outputs "dry contacts"
Replies: 9
Views: 511

Re: Monitoring A/C redundancy box outputs "dry contacts"

You need only the pis gnd or 3.3 v, but not both. Err... I suppose it could be done that way but find a tutorial on reading a push-button with the programming language of your choice. Typically, we either connect the gpio pin we will monitor to either 3.3v or ground through a resistor of somewhere f...
by ElEscalador
Tue Jun 23, 2020 12:56 pm
Forum: Troubleshooting
Topic: Using IR sensor as a triggering event
Replies: 10
Views: 328

Re: Using IR sensor as a triggering event

Is this a PIR motion sensor or an IR sensor module that toggles from high to low or an IR sensor that you read with an analog to digital converter and determine a threshold that you call triggered? In any case, the first step is to write a loop that takes the pictures - perhaps not "professional" bu...
by ElEscalador
Tue Jun 23, 2020 12:37 pm
Forum: General discussion
Topic: in need to help with passing radar module signal to rpi
Replies: 8
Views: 548

Re: in need to help with passing radar module signal to rpi

A couple of thoughts: 1. I'm not familiar with the library you're using, but I don't see the internal pullups explicitly set. If the motion pin goes high for motion detected, your pullup resistor will need to be pulling low. Perhaps check the output of the motion pin with a voltage meter to see if i...
by ElEscalador
Mon Jun 22, 2020 12:30 pm
Forum: General discussion
Topic: in need to help with passing radar module signal to rpi
Replies: 8
Views: 548

Re: in need to help with passing radar module signal to rpi

Besides above advice, there are many things called "rear module" that behave differently. Please provide a part number and/or link or we won't be able to give accurate advice.
by ElEscalador
Mon Jun 22, 2020 2:48 am
Forum: Beginners
Topic: How to change the duty cycle of hardware pwm in pigpio?
Replies: 3
Views: 183

Re: How to change the duty cycle of hardware pwm in pigpio?

It appears you initialize dc at 500k then set PWM off and running. Then the first check finds it above 100k so subtracts 10k. Then your last if statement tells it not to do anything if dc is less than 500k, which of course it is. So it remains. I think.. I'm tired and python always looks weird to me.
by ElEscalador
Wed Jun 17, 2020 9:21 pm
Forum: Beginners
Topic: GNSS Module
Replies: 8
Views: 438

Re: GNSS Module

Connections via USB have less accuracy compared to serial, they also often miss the PPS connectivity. I'm trying to understand how connection type changes sensor accuracy. Is there any link or a supplier that is in the USA? thank you A $10 FTDI makes any serial device USB. Check Amazon, Adafruit, P...
by ElEscalador
Wed Jun 17, 2020 2:06 pm
Forum: Automation, sensing and robotics
Topic: Detect object (not visual detection)
Replies: 6
Views: 509

Re: Detect object (not visual detection)

Bar code and laser reader?
An extra tab on the folder with a certain pattern of holes punched out you can detect with microswitches?
by ElEscalador
Wed Jun 17, 2020 1:43 am
Forum: Beginners
Topic: GNSS Module
Replies: 8
Views: 438

Re: GNSS Module

Most or all with either ttl serial or USB (or I2C) will work with the Pi. I'd avoid the ones that are very inexpensive (and any labeled only GPS and not mentioning GNSS). Unless I need RTK (2mm accuracy) I am fond of the GPSV5. It's very simple to just plug into either the gpio serial or USB (althou...
by ElEscalador
Fri Jun 12, 2020 8:32 pm
Forum: Automation, sensing and robotics
Topic: L298N Driver Motor and 9v Battery Packs
Replies: 4
Views: 341

Re: L298N Driver Motor and 9v Battery Packs

I can't recommend enough getting a rechargeable battery pack - I am fond of power tool batteries because I always have them around... you can get a kit with a 14.4 volt nimh battery or two and a charger for the cost of just a few cycles of disposable batteries... just pick one with tabs that are eas...
by ElEscalador
Fri Jun 12, 2020 1:55 pm
Forum: General discussion
Topic: GPS start-end point
Replies: 2
Views: 145

Re: GPS start-end point

Pidd is correct - you'll need other sensors for heading. Magnetometers are tricky since so many things can warp the Earth's magnetic field. You can (and must) calibrate to compensate for the static (relative to the sensor) magnetic interference from the body of the robot, but that's doable. Motors m...

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