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by amcdonley
Wed Jul 31, 2019 5:29 pm
Forum: Automation, sensing and robotics
Topic: Agree? “IMU worthless for simple robots' x, y, heading?”
Replies: 9
Views: 638

Agree? “IMU worthless for simple robots' x, y, heading?”

Found a phenomenal [90 page introduction and analysis](https://arxiv.org/pdf/1704.06053.pdf) (university level, but first and last sentence of some paragraphs are understandable): Manon Kok, Jeroen D. Hol and Thomas B. Sch ̈on (2017), ”Using Inertial Sensors for Position and Orientation Estimation”,...
by amcdonley
Wed Jul 31, 2019 5:16 pm
Forum: Automation, sensing and robotics
Topic: Robot Shared Values / DB impact on RPi SD card
Replies: 2
Views: 245

Robot Shared Values / DB impact on RPi SD card

My robot is nearing the point of needing a place to share more state and history between Python processes. Currently I have a “json data module” that abstracts access to a few rarely written values persisted on the SD card file system, and two logger files which are written to once or twice an hour....
by amcdonley
Sun Jul 28, 2019 4:07 am
Forum: Automation, sensing and robotics
Topic: 'Uninteruptible' Power Supply
Replies: 3
Views: 406

Re: 'Uninteruptible' Power Supply

strongly suggest this UPS, I use it with my desktop RPi for over a year with no off time, even through hurricanes.

https://lifepo4wered.com/lifepo4wered-pi+.html
by amcdonley
Thu Jun 20, 2019 5:46 pm
Forum: Automation, sensing and robotics
Topic: Let's give voice to my robot... Speaker problem
Replies: 11
Views: 1059

Re: Let's give voice to my robot... Speaker problem

drotosclerosi wrote:
Wed Jun 19, 2019 2:29 pm
So i bought this little speaker

I'm just worried about the weight: could a 42grams speaker connected to the 3.5 mm jack damage it in any way?
Use a short extension cable and velcro the speaker to your bot.
by amcdonley
Tue Jun 18, 2019 12:52 pm
Forum: Automation, sensing and robotics
Topic: irritating battery limits
Replies: 21
Views: 1631

Re: irritating battery limits

OK, so i took a look at that specialized battery, and it definitely looks intriguing. The problem lies in that this solution would only work for the pi part of the robot, and would not allow function for the rest whilst charging. Ideally, I would need a circuit that could take a signal from a GPIO ...
by amcdonley
Sun Jun 16, 2019 10:19 pm
Forum: Automation, sensing and robotics
Topic: irritating battery limits
Replies: 21
Views: 1631

Re: irritating battery limits

Have you looked at this phenomenal UPS https://lifepo4wered.com/lifepo4wered-pi+.html ?

I have the earlier version running a desktop RPi continuously for six months at a time. I like to update the OS periodically and sometimes that requires a reboot.
by amcdonley
Sun Jun 16, 2019 1:02 pm
Forum: Automation, sensing and robotics
Topic: How to maximize Robot Play Time - NiMH Batteries?
Replies: 6
Views: 536

Re: How to maximize Robot Play Time - NiMH Batteries?

Are you using the batteries with UPS to run both the RPi and the motors?? My bot is built upon the Dexter Industries GoPiGo3, which provides the power management and isolation using a single 7 to 12 v 2.5A source. Note: I have found it best for me to start from a supported platform. I spent/wasted ...
by amcdonley
Sat Jun 15, 2019 12:42 pm
Forum: Automation, sensing and robotics
Topic: Let's give voice to my robot... Speaker problem
Replies: 11
Views: 1059

Re: Installing OpenCV

THe fact is that i'm already in big pain installing opencv for facial recognition If you are willing to use Python and not virtual environments: (From https://www.pyimagesearch.com/2018/09/19/pip-install-opencv/) sudo apt-get update && sudo apt-get upgrade sudo apt-get install libhdf5-dev libhdf5-s...
by amcdonley
Sat Jun 15, 2019 12:17 pm
Forum: Automation, sensing and robotics
Topic: How to maximize Robot Play Time - NiMH Batteries?
Replies: 6
Views: 536

Re: How to maximize Robot Play Time - NiMH Batteries?

I usually use Hobby Lipo batteries for all my projects as they are cheaper and have higher energy density as well as can handle much higher amps if needed. But I would guess you are not running them in a UPS (uninterruptable power supply) mode that allows connecting/disconnecting the charging sourc...
by amcdonley
Fri Jun 14, 2019 7:23 pm
Forum: Automation, sensing and robotics
Topic: Let's give voice to my robot... Speaker problem
Replies: 11
Views: 1059

Re: Let's give voice to my robot... Speaker problem

My current bot first used a "Wired Rechargeable Speaker": https://www.amazon.com/Otimo-Rechargeable-Speaker-Design-Smile/dp/B01DQ6RE4O Carl_Charging_After_Marathon.jpg This was an OK speaker, but a bit of a pain because I needed to recharge it separate from recharging the bot, and I had to get on th...
by amcdonley
Fri Jun 14, 2019 2:49 pm
Forum: Automation, sensing and robotics
Topic: How to maximize Robot Play Time - NiMH Batteries?
Replies: 6
Views: 536

Re: How to maximize Robot Play Time - NiMH Batteries?

BAck to basics. There are only four possible problems here; 1. The charger is not doing its job 2. The battery pack is faulty and not holding a charge 3. The robot is using more power than expected 4. The Juice data is bullshit. I suspect you either have a dodgy charge situation, or a bad cell in t...
by amcdonley
Thu Jun 13, 2019 7:02 pm
Forum: Automation, sensing and robotics
Topic: How to measure distance with the raspberry pi camera
Replies: 4
Views: 963

Re: How to measure distance with the raspberry pi camera

For a PiCamera fixed to a bot with a fixed/known pointing angle, the distance to the bottom line of the image is a known, fixed number. I have a PiCam v1.3 on my bot: 5MP 1080p30 2592 x 1944 pixels 35mm focal length equiv. focus 1 m to inf. H 53 deg x V 41 deg f/2.9 (Use 1296 x 976 and 2x2 binning f...
by amcdonley
Thu Jun 13, 2019 6:34 pm
Forum: Automation, sensing and robotics
Topic: irritating battery limits
Replies: 21
Views: 1631

Re: irritating battery limits - this works for my bot

A subject dear to my heart, this is - how to recharge a robot without shutting it down? (In my case because the bot has no wakeup timer function.) Carl Recharging On His Dock.jpg How I solved it for my GoPiGo3 robot: 1) Eight 2800mAh NiMH AA-cells (series connected) 2) Twin pigtails in parallel off ...
by amcdonley
Thu Jun 13, 2019 4:38 pm
Forum: Automation, sensing and robotics
Topic: How to maximize Robot Play Time - NiMH Batteries?
Replies: 6
Views: 536

How to maximize Robot Play Time - NiMH Batteries?

My question: how to maximize "play time" for my robot? I have been using EBL NiMH rechargeable batteries in my Raspberry Pi robots for the last five years, originally six 5000mAh C-cells, and for the last year - eight 2800mAh AA-cells in my GoPiGo3 robot Carl. My robot charges the eight AA-cells for...
by amcdonley
Thu May 02, 2019 4:13 am
Forum: Raspberry Pi Desktop for PC and Mac
Topic: geekbench4 file not found weirdness
Replies: 4
Views: 547

Re: geekbench4 file not found weirdness

fruitoftheloom wrote:
Wed May 01, 2019 3:48 pm

Pixel Desktop was renamed nearly 2 years ago:

...

Regards x86-64 64bit version, there has never been a release ...
Great info - thanks.

I'm certainly not hampered by the 32-bit version in any way. At least now I understand the reasons. Double thanks.
by amcdonley
Thu Apr 25, 2019 2:18 am
Forum: Raspberry Pi Desktop for PC and Mac
Topic: geekbench4 file not found weirdness
Replies: 4
Views: 547

Re: geekbench4 file not found weirdness

From https://www.geekbench.com/download/linux/ : System Requirements Ubuntu 14.04 LTS or later 2GB of RAM Perhaps they really do mean ' Ubuntu ', and not just some similar-looking Debian-based Linux distribution? Apparently. I guess I was lucky that the 32bit version ran. Interestingly, my score wa...
by amcdonley
Tue Apr 23, 2019 2:43 pm
Forum: Raspberry Pi Desktop for PC and Mac
Topic: RPi Desktop x86 Canon Printer Installation Problem
Replies: 5
Views: 1020

Re: RPi Desktop x86 Canon Printer Installation Problem

I'm stuck on this same issue (a year later) with the 11 Apr 2019 X86 Debian 9 with PIXEL desktop for PC and a Canon MX860 printer.

Agree that this is not a PIXEL desktop issue. Posting here in case anyone has found a solution.
by amcdonley
Tue Apr 23, 2019 2:38 pm
Forum: Raspberry Pi Desktop for PC and Mac
Topic: geekbench4 file not found weirdness
Replies: 4
Views: 547

geekbench4 file not found weirdness

I am running Geekbench-4.3.3-Linux on (uname -a): Linux AlanLaptop 4.9.0-8-amd64 #1 SMP Debian 4.9.144-3.1 (2019-02-19) x86_64 GNU/Linux (Raspberrypi.org X86 Debian with RaspberryPi (formerly PIXEL) desktop for PC 11Apr2019) on a Toshiba Portege Z935 with 5.73GB memory Toshiba Version 6.80 BIOS, Int...
by amcdonley
Thu Aug 30, 2018 12:00 pm
Forum: Automation, sensing and robotics
Topic: NiMH Batteries - Selecting Safe Shutdown Limit
Replies: 5
Views: 656

Re: NiMH Batteries - Selecting Safe Shutdown Limit

The risk with multiple NiMH cells in series is that their capacities are or become different enough such that (because of the "cliff edge") one cell reaches zero while the others still have sufficient voltage that the powered circuit continues to operate and draw current. Operation with current for...
by amcdonley
Thu Aug 30, 2018 11:37 am
Forum: Automation, sensing and robotics
Topic: NiMH Batteries - Selecting Safe Shutdown Limit
Replies: 5
Views: 656

Re: NiMH Batteries - Selecting Safe Shutdown Limit

... Set that too high, and [it] wouldn't run long enough on one charge; set it too low and the life of the battery was compromised, so ...set it to ... 1.1v cut-off So along came some cowboys, ... cut-off became 1.0v. ... life of the pack was reduced, ... almost no extra run-time, because of the cl...
by amcdonley
Thu Aug 30, 2018 12:38 am
Forum: Automation, sensing and robotics
Topic: NiMH Batteries - Selecting Safe Shutdown Limit
Replies: 5
Views: 656

NiMH Batteries - Selecting Safe Shutdown Limit

I just built a new bot based on the GoPiGo3 platform and need to select a safe shutdown voltage limit. * I am using 8 AA size 2300 mAH NiMH cells and a Tenergy multi-voltage peaking charger. * (The GoPiGo3 has a get_battery_voltage() function which returns a value which is 0.6v less than the actual...
by amcdonley
Thu Jul 05, 2018 12:05 pm
Forum: Troubleshooting
Topic: sudo apt-get update uses IPv6 - have to force IPv4 to succeed
Replies: 2
Views: 1984

Re: sudo apt-get update uses IPv6 - have to force IPv4 to succeed

Just a thought: what happens if you use Google DNS server?
by amcdonley
Wed Dec 20, 2017 7:55 pm
Forum: General discussion
Topic: Boinc not working after upgrade to Stretch
Replies: 2
Views: 522

Re: Boinc not working after upgrade to Stretch

I had to do the same thing twice after early Stretch updates. Did an update this week that did not affect my BOINC.
by amcdonley
Fri Dec 15, 2017 5:32 pm
Forum: Troubleshooting
Topic: Debugging Motion and the Raspberry Pi Camera
Replies: 1
Views: 973

Re: Debugging Motion and the Raspberry Pi Camera

This worked for me this morning: Motion for Raspberry Pi sudo modprobe bcm2835-v4l2 sudo /etc/modules to add: # camera with v4l2 driver bcm2835-v4l2 reboot sudo apt-get install motion sudo cp /etc/motion/motion.conf /etc/motion/motion.conf.bak sudo nano /etc/motion/motion.conf to change: rotate 180 ...
by amcdonley
Fri Dec 15, 2017 12:12 am
Forum: Troubleshooting
Topic: RPi3 WiFi interference?
Replies: 0
Views: 335

RPi3 WiFi interference?

Anecdotally, when I have two RPi3 on the same subnet (10.0.0.x on US channel 6), or even same subnet, different WiFi networks (SSID1 and SSID2 in same room, two routers on different channels - US 3 and US 6) I often see: sudo apt-get update Ign:1 http://archive.raspberrypi.org/debian stretch InRelea...

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