Raspberry Pi Forums

Joel_Mckay

try your home dir ;-) cd ~ ls -lAh Also, we recently did a OpenCV 3.4.5 build for legacy Stretch based ROS: https://sourceforge.net/projects/micrometer-cnc-on-raspberry-pi/files/2019_jul4_v0.1rc2_current/ I have talked with some of the awesome devs about openCV 4, and specifically about the perils o...

Joel_Mckay

Have a look at ROS or MRPT.

You will need to be more specific about the platform, as guidance and navigation are separate classes of problems.

Cheers.
J

Joel_Mckay

If you use an overlayfs then its only the upper of the merge mount that is readwrite so the only files are ones written to or writing are in ram and fetched from lower by the CoW (copy on write) of the overlayfs. The overlayfs method also allows one to track down which programs tend to slowly flood...

Joel_Mckay

Is ROS necessary for making the robot. Not always, but it will train you how to re-use a standard popular platform, and a minimal remote sensor/driver API. Both these concepts are important for understanding more complex platforms... yet you can start with just the turtle-bot sim demos. And i think...

Joel_Mckay

The MCP3008 may require Vref to be less than or equal to Vcc (3.3v)... I'd use a Voltage divider on the sensor output to scale into a safe input range under 2.7v until this property is known.
https://en.wikipedia.org/wiki/Voltage_divider

Joel_Mckay

In general, one must make several choices when designing a platform, and define the task you are trying to solve. Like any software specification, having a clearly defined finish line will constrain the complexity of your project. ROS ( https://wiki.ros.org/melodic ) is the current standard of sever...

Joel_Mckay

All of that will fail 100%. There's no NTP installed in Raspbian by default. Time sync is done with systemd-timedatectl. Even with ntp added after there's no ntpdate any longer (replaced with ntpd -q -g). And yes, 2 of the above lines will likely not work (20% fail to be exact)... depending on the ...

Joel_Mckay

If your device has a max time adjust forwards limit in NTP, and was left off too long... than SSL issues can occur. Try running: date sudo service ntp stop sudo ntpdate -s us.pool.ntp.org sudo ntpd -gq sudo service ntp start sudo ntpdate -u time.nist.gov date Then reboot the machine to retry your SS...

Joel_Mckay

InvenSense gyros tend to drift pretty badly/fast, and setting a low-pass down-sampling filter only gets you so far. A slower magnetometer is important as it usually offers the only true consistent directional reference using magnetic declination (once calibrated). Unfortunately, these "9-axis" units...

Joel_Mckay

They mention a 38KHz amplifier+de-modulator that runs at 3.3v just fine: https://www.adafruit.com/product/157 Keep in mind there are many different remotes, IR wavelengths, and any one of 34/38/40/56 kHz modulations. There were a few receivers that could auto-select several frequencies, but I can't ...

Joel_Mckay

sudo apt-get install lirc Then search for a tutorial about setting up the interface: http://alexba.in/blog/2013/01/06/setting-up-lirc-on-the-raspberrypi/ https://learn.adafruit.com/using-an-ir-remote-with-a-raspberry-pi-media-center/lirc This program has been around for a long time. https://gist.git...

Joel_Mckay

This camera likely supports tethering: http://gphoto.org/proj/libgphoto2/support.php People use several tricks to trigger the shutter in a lightning storm, and as they must be fast it usually limits the complexity of the circuit. In general, with a high-end capture rig ( https://www.krontech.ca/ ) y...

Joel_Mckay

The reason many people use the bme280 is that it is reliable, accurate, and repeatable. Swapping sensors can be a pain, but sometimes using a different chip just works out being easier, and wastes less of your time in the long term. https://www.raspberrypi.org/forums/viewtopic.php?f=28&t=239157 Actu...

Joel_Mckay

The reason many people use the bme280 is that it is reliable, accurate, and repeatable. Swapping sensors can be a pain, but sometimes using a different chip just works out being easier, and wastes less of your time in the long term. https://www.raspberrypi.org/forums/viewtopic.php?f=28&t=239157 Actu...

Joel_Mckay

I usually prefer a native cross platform C++ lib like wxwidgets for GUI stuff: https://wxwidgets.org/ (it has its own set of constraints, but works on most platforms) If wxglade wasn't so unstable, the visual layout scaffold coding experience would be trivial: http://wxglade.sourceforge.net/ https:/...

Joel_Mckay

Raspbian has "Raspberry Pi Desktop" which is a fork of LXDE......... We use a minimal MATE package on the Raspbian Stretch Lite image (MATE image itself seemed out of date), as it was more consistent with traditional Ubuntu/Mint style community documentation and supported a configurable gpu composi...

Joel_Mckay

fruitoftheloom wrote: Why do you believe the OP is running Gnome Desktop .

It is a common issue people may have, and the "volume control applet" is usually more meaningful than "pactl list; aplay -l;" or fumbling in the "alsamixer" terminal interface with F6 menu.

I assumed they are using linux...

Joel_Mckay

If you have the gnome desktop : 0. exit all active media players 1. right-click Speaker icon in the upper right hand of screen to select "Sound Preferences" 2. click "hardware" tab to see if driver is active 3. click "output" tab and select alternate default output line 4. click "hardware" tab again...

Joel_Mckay

We use the BME280 (several years of uptime), and I dumped the DHT/SHT units we sampled in the e-waste recycling bucket after testing the repeatability over several months (cleaved the leads off to ensure they stayed gone). I suggest you do the same... as although there will be a few people who insis...

Joel_Mckay

Many low-end sound-cards use a rather noisy class-d amplifier for the audio output. The picture/site doesn't really give enough details about the amp or sound-card. However, if a pair of headphones in the sound-card sound fine, than there are several possibilities: 1. you are over-driving the input ...

Joel_Mckay

Several big red mushroom buttons that say "Emergency Stop" to cut the main power for a start. ;-) The rather macabre "Dead man's switch" predates the modern computer age: https://en.wikipedia.org/wiki/Dead_man%27s_switch This is usually implemented with several redundant pic/atmel mcus with their ow...

Joel_Mckay

Why is that so hard to find? It is not difficult, but may be counter-intuitive to new users given the signal-to-noise ratio in web search results. LMGTFY: https://www.kali.org/tutorials/secure-kali-pi-2018/ Since the OS files are signed within apt one can usually just encrypt the user /home on publ...

Joel_Mckay

A very general and broad statement, and IMHO inaccurate. I invite you to specify an ISO Standard that a RPi would fail to meet, but a PLC would. ... Lecture over, apologies to all. Excuse my obsession with anyone who makes sleeping, generalist statements, especially in a forum for beginners and stu...

Joel_Mckay

In general, there are many processes that can update, report, and download data. From your description, it sounds like IT debt... where the employee disappeared.... note, over 90% of security problems are usually current/former staff who are familiar with the systems. If you exposed an OS to the pub...

Joel_Mckay

You probably should look into a proper industrial HMI for you vendor's PLC, and a commercial VPN-appliance/router designed for this kind of application. The Pi is not intended for industrial environments, and will not meet legal or safety certification requirements without design specific lab paperw...

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