Raspberry Pi Forums

amcdonley

Thank you - great response. consider in memory databases https://en.wikipedia.org/wiki/List_of_in-memory_databases Or. if it suits you, a faster in memory key-value datastore like LMDB https://en.wikipedia.org/wiki/Lightning_Memory-Mapped_Database I have heard of, but know nothing about, SQLite whic...

amcdonley

blimpyway wrote: ↑
Wed Jul 31, 2019 8:09 pm
try to make a simple two wheel balancing bot (segway bot) without an imu.

Understandably impossible for the "keeping its head up" function, but can it provide accurate (world frame: x, y, theta)? It's a serious question. Am I wrong about that application of IMU?

amcdonley

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”,...

amcdonley

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....

amcdonley

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

amcdonley

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.

amcdonley

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 ...

amcdonley

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.

amcdonley

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 ...

amcdonley

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...

amcdonley

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...

amcdonley

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...

amcdonley

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...

amcdonley

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...

amcdonley

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 ...

amcdonley

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...

amcdonley

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.

amcdonley

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...

amcdonley

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.

amcdonley

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...

amcdonley

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...

amcdonley

... 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...

amcdonley

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...

amcdonley

Just a thought: what happens if you use Google DNS server?

amcdonley

I had to do the same thing twice after early Stretch updates. Did an update this week that did not affect my BOINC.

Search found 184 matches

Re: Robot Shared Values / DB impact on RPi SD card

Re: Agree? “IMU worthless for simple robots”

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

Robot Shared Values / DB impact on RPi SD card

Re: 'Uninteruptible' Power Supply

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

Re: irritating battery limits

Re: irritating battery limits

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

Re: Installing OpenCV

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

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

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

Re: How to measure distance with the raspberry pi camera

Re: irritating battery limits - this works for my bot

How to maximize Robot Play Time - NiMH Batteries?

Re: geekbench4 file not found weirdness

Re: geekbench4 file not found weirdness

Re: RPi Desktop x86 Canon Printer Installation Problem

geekbench4 file not found weirdness

Re: NiMH Batteries - Selecting Safe Shutdown Limit

Re: NiMH Batteries - Selecting Safe Shutdown Limit

NiMH Batteries - Selecting Safe Shutdown Limit

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

Re: Boinc not working after upgrade to Stretch