Raspberry-PI : Robot Tank Treads Progress

I have created a wheel design for driving the tank tracks for my mini Raspberry PI robot. The STL file is available here on tinkercad.com.

Also found a couple worm gear motors that will run at 30rpm at 12V (Unloaded) on Amazon.ca . They have a 6mm D-shaft that is a little short, but should be ok.

Next step is to build a 3D design for mounting the motors and holding the wheels in position within the track.

Will try to post some pictures soon.

3D Printer Wanhao Duplicator i3 Plus!

A friend of mine is really into 3D printing, it looked like so much fun that I bought a ‘Wanhao Duplicator i3 Plus’ for $649 from the same place he got his, Spool3d.ca. It has been a great experience so far. I have been printing almost non-stop for the last month! This printer is very well built and I can definitely recommend it to anyone wanting to get started.

I have been using tinkercad.com for all my designs, here are links to a few of the models I have built. I am slowly building up a tank type robot for my Raspberry Pi. Fun stuff!

Nerf to Picatinny Rail Converter
Modified Picatinny Riser For Airsoft
8cm by 2cm Tank Treads for my Raspberry Pi Robot Project
Tank Tread Wheel for the Tank Treads

Here are my almost finished tank treads…

Review of EteckCity ‘Measure Up’ Digital Multimeter

This is the second product that EtekCity sent me for free for my honest review as part of their EtekCitizen program.
I requested this multimeter from them because I am constantly looking for my voltmeter, and needed an extra one to leave with my RC gear. This one retails for $16.98 on amazon.ca.

Package for EtekCity Digital Multimeter
Package

I have used this quite a bit in the last 2 days. I have too many large batteries around (for my Dalek, and a wooden go kart I built ), so I decided to give them all a check as well as test some continuity on some of the circuits I have built for my Dalek. I also did some resistive measurements on some bits of RC stuff as well. So far I am happy with this multimeter, it seems to work as expected. Is has a fast settle time (unlike my old tester) and the backlight makes reading the display very easy.
EtekCity Digital Multimeter
EtekCity Digital Multimeter

EtekCity Multimeter backlight
Backlight

It feels very solid, and runs on a 9V battery. The only problem I have with it is that there is no battery cover, instead you need to take the unit apart (2 screws) to change the battery. Also it does not auto power down, so try not to forget to turn it off.
EtekCity Digital Multimeter taken apart
Disassembled for battery replacement check

Conclusion: I am pretty happy with it, it will have a permanent spot on my RC workbench.

Review of EtekCity ‘Roverbeats Bravo’ Headset (3.5mm with microphone)

So I signed up for EtekCitizen free products in exchange for honest reviews to give it a try (ie. They gave me this ‘Roverbeat Bravo’ headset for free so take my review as a paid advertisement). I recently bought a food scale from them for weighing my RC planes and components and was thrilled with the quality of the scale, so I signed up hoping to get more great quality stuff as I was looking for a gaming headset for the kids. When I received the shipment it was well packaged.

EtekCity Headset with microphone
Package

It has very decent sound quality compared to my other much more expensive headset (AKG, K99 Perception), and worked perfectly with my Windows 10 pc and google hangouts, but it definitely feels a bit cheap, the ear padding is super soft and thin and I worry that it will wear out very quickly, only time will tell.
EteckCity Headset with Microphone 3.5mm jacks
Out of the box

I am used to much higher quality audio gear, but this headset retails for $17.99 on amazon.ca so of course I am not going to find it up to par with my usual gear. However for a $17.99 price I would say it is actually a good value for money, I have given it to my kids and they have been using it for their gaming and loving it.
In conclusion: Not high end (duh, look at the price), but good value and so far it has been great for kids gaming. Happy kids = happy dad.

RC Simulator upgraded to three.js r74

WebGL RC Flight simulator view of landing strip with Flying Stick model selected
I got tired of seeing all the three.js warnings and errors in the flight sim, so I upgraded to r74 and fixed a few bugs caused by the upgrade. I also added more trees around the flight field and changed the aircraft weapons:

  • Gun1 is now smaller bullets and fast rate of fire
  • Gun2 is the old gun1 with a slow rate of fire
  • Bomb1 is the same
  • Added Bomb2 as a bigger sphere with a slow rate of fire

Python Article on Unit testing

python One of the difficulties in learning a new language is re-learning how to do some common things like unit-testing. Today I was referred to a great article on Python and ‘mocking’, and it was interesting enough that I decided I would post a link to it. www.toptal.com/python/an-introduction-to-mocking-in-python These guys at toptal.com have a blog with quite a few interesting articles on software development, I will be checking their blog regularly for new articles.

RC Flight Sim Physics engine Update

RonsRCSimStickTrainer
So I was just sitting around this weekend, and out of nowhere I realized that I had a flaw in the RC Flight Simulator Physics engine. I wasn’t even thinking about the simulator, I was thinking about my last RC flight and how tight a turn I could pull with my FT-Bushwacker without snapping the wings in half (grin), which lead me to think about the simulator. Funny how the brain works!
I realized that my inertial tensor was being calculated on the aircraft before I had shifted the model coordinates to ensure the c.g. was at coordinate (0,0,0). I had thought that the inertial tensor calcs would not be affected by that originally, oops. After writing a small function to shift the model coordinates, I tried flying a few aircraft and it made a huge difference. The rotation seemed much more realistic and I was able to reduce the rotational damping factor I had been using (to prevent infinite rotation speed) and still have stable calculations. Right now I have cleaned up the code and some of the hacks that I made to some of the model parameters to get them to fly realistically. Some models still do not fly at all realistically, but most are better. The FT-VersaWing still flys incorrectly, oh well, a work in progress…

Remote Motion Detection, Summary Image

I have been using the remotemotion.py script for a week now, and it has been working great. As I was looking through the images for the day I realized that the thing I hated most about motion detection software is that there were so many images to look through that it took a long time to find anything. I have a lot of traffic on my street and therefore many motion images to check through to see if anything suspicious has happened. I decided to group all the images into a sequence for each event, and save the ‘best’ summary image to a new directory for a very fast overview of activity. Surprisingly, my simple method to find the best image works very well. The algorithm is explained on this page with a link to the code repo. Now I can quickly go through the summary directory and delete images as I review them without losing the original images. This has saved me so much time!

Remote Motion Detection For the Raspberry Pi or Other devices

python
I felt motivated last night, so I wrote a python script that will monitor an unlimited (limited by bandwidth and CPU) number of Raspberry Pi Cams or webcams on your network for motion and save motion images in folders organized by day. I did this because I was frustrated by ‘motion’ and ‘zoneminder’. So now I finally have something that works for me! I hope someone else finds this useful as well.

Remote Motion Detection

Update to Flight Sim and comments about wordpress

I have disabled comments on my site for a long time now. Anyone who runs WordPress will probably understand why. Even without plugins (other than Akismet) installed it was taking me way too much time to clean up my site on a weekly basis due to hack after hack. I think I have had 4 major automatic updates to my WordPress this month, but I really doubt it will solve anything, so I don’t recommend WordPress for anyone about to start a blog.

It would have been much easier for me if I had just written raw html/php from the start. It would be too much work to change things now, so disabling comments permanently is the easiest solution. I would rather spend my time on robotics and my flight sim than waste it rewriting my website.

Speaking of my flight simulator, I finally fixed a bug in the rcflight sim for mobile devices. I had an error that was causing the touch interface code to fail. Also the new code I wrote to deal with different controllers would fail the first time you opened the page. These are fixed now, wish I could ask for comments but … you know …