Repair Notes for Jaibaile 1:43 RC drift car

 

A friend recommended this RC toy car from Jaibaile. It's a 1:43 scale RC car that's really zippy. The gyroscope on board seems to make it corner more like a real car, although I'm still trying to understand exactly what the gyro does. It's been a ton of fun and great value. The car syncs to its remote on power-on so you can run several at once to race. However, mine has spent more time on the shelf waiting for repair than it has spent ready to run. Here's what I've discovered about repairs:

Car turns on, but frequently de-syncs from the remote

The lights turn on, and may even control normally for a while, but will stop responding to the RC remote after a while. For me, this issue was low battery voltage. Replacing the batteries in the remote and charging the car helped, but the problem quickly returned. In the end, the permanent fix was to swap in a replacement LiPo battery. A small, 3.7V battery did the trick, but I did have to swap the connector to fit the connector type that came on the old battery

The steering is jittery

The next problem I had was that the wheels would jitter or vibrate while turning. This one turned out to be a burnt-out servo. The servo that came with the car doesn't have any markings and doesn't seem to be a standard size so finding a replacement was a real challenge. I did find servo model S0002P from Surpass Hobby that's a near-enough fit. The plastic cover that holds the servo-motor in place doesn't fit over the S0002P so I had to super-glue it to the frame, which isn't ideal. But it does seem to have the same voltage characteristics and range of motion as the original. The S0002P also comes with the wrong connector so I had to swap out the connector from the old, broken servo. Note that the seller I linked has several models on the same page, but only the S0002P fits.

Front wheel stops turning / car spins around front wheel

One of my front wheels stopped getting power from the drive motor. It would turn freely, and steer, but not drive making the whole car spin around that front wheel. This one turned out to be a snapped tie rod between axle and the wheel. Super glue didn't create a strong enough bond to simply glue it back together, but it might have worked better if I was able to clean the grease off the tie rod more thoroughly. Instead, I used a hobby knife to cut a new tie rod from some left-over plastic sprue from another project.

I have a feeling this is not the end of the repairs this car will need. I'll keep posting if I find anything else worth sharing.

 

 

Free Linear Graph Template with Error Bars, Max and Min, and Feedback for IB Physics

Yet again, I've remade the IB Physics Graphing Template. This latest version is the best one yet:

IB Physics Graphing Template

 

Try it out. It's totally free and runs in your browser: http://beepboopmachines.com/

Features:

• Graphs linear data with error bars and automatically generates a best fit, a steepest (max) fit, and a shallowest (min) fit.
• You can reshape the trendlines by clicking and dragging them if you happen to not like the auto-generated trendlines.
  
• Produces feedback about your data and graph. This will help you check to make sure you didn't miss anything important (like a graph title), and can also help you identify important talking points for a conclusion or evaluation.
  
• Runs in your browser for compatibility with Windows, Mac, Linux, and even mobile or tablet!
  
• You can share your graph as a URL if you want other people to work with your example. Great for teachers making examples, scaffolding, or tutorials.
  
• Data table automatically grows to handle large amounts of data
• You can enter data in a variety of forms: decimal (eg 0.00045), scientific (eg 4.5x10^-4), percentages (eg, 15%), and bizarro calculator format (eg, 4.5E-4)
• The overall size, gridlines, titles, labels, units, and symbols in the graph can be edited by clicking anywhere on the title, legend, or axis labels. 

You can edit the properties of the graph by clicking anywhere on the title, legend, or axis labels

 

Let me know in the comments what you think. Some known issues:

• I haven't tested the application in every browser and OS. 
• Sometimes produces some pretty extreme max and min slopes. I haven't developed a good algorithm to handle every case. Drag the lines around if it comes up with lines you're not happy with
• The performance of the program will drop as you add more and more data. 
  

Use Existing SQLite Database in Android using SQLDroid JDBC Driver

In Android the recommended SQLite database access method is to create a new database using the SQLiteOpenHelper class. However I wanted to be able to load a pre-existing SQLite database into an Android application and access it with a JDBC driver.

The reason is that I want my students to be able to play around with making a database with an application like SQLite Browser and then build on their work in their applications. I also wanted all of my students using similar database access methods so they can help each other as much as possible so I wanted them using JDBC. I've found that it is possible but first a few warnings:

1. This method is inappropriate for large databases as it duplicates the whole database doubling the memory footprint
2. This method also pulls in an external JDBC library, SQLDroid, further increasing footprint size
3. The SQLDroid library is not guaranteed to be complete or correct across all android devices

But if you still want to load your existing SQLite database into your Android project and access it with a JDBC driver, here's how you can do it. I've started a fresh, empty project to try to keep it as simple as possible:

Move your existing SQLite database into your projects 'assets' folder

First you may need to create your assets folder if you don't see it in your project already

- right click on your project, select New > Folder > Assets Folder

- add the 'assets' folder to your main project:

- Navigate to your assets folder in your file browser (finder or windows explorer etc). I found it in /app/src/main/assets

 - drag and drop your database into this folder and it should appear in android studio. My database is a database of birds.

(Now is a good time to run your program and make sure it still runs without run-time errors!)

Add code to your project to copy your database into internal memory on the phone

The assets folder is a read-only directory that gets packaged up into your .apk to load on the phone. But we want to continue to add and remove from the database so when the app is run for the first time only, we will copy the database into internal memory.

- In your main activity, create a method called LoadDatabase and call it in the onCreate method. You'll also need a string called 'dbName' and four imports shown below for later

- In LoadDatabase,  check to see if there is already a database in Internal Storage. If not, copy it over from Assets

(Now is a good time to run your program and make sure it still runs without run-time errors!)

If you're running your phone at API level 23 or less, you should be able to use Android Device Monitor to see your new database file in Internal Storage after your program runs! 

 - Android/tools/Android/Android Device Monitor

 - select the file 'explorer' tab

 - navigate to data/data//files

Add the SQLDroid JDBC Driver to your project

Open your Gradle file (Module: app) and add this line:

- Save and Sync your Gradle file

(Now is a good time to run your program and make sure it still runs without run-time errors!)

Access your database in Internal Storage using your JDBC driver

- back in the main activity, I've added another method called 'TestDatabase' and called it from the onCreate Method

- We'll need a few more imported classes:

- Then we can load the SQLDroid JDBC driver and use it to make a connection to our database in Internal Storage.

In this case I'm using the JDBC driver to read all the 'BirdSpecies' records from my table 'BirdList' but you can use other SQL methods to read and write whatever is appropriate for your database

Run your program

Run your program and hopefully your data will appear as a toast as soon as the program loads. Here you see sparrow appear as a 'Toast'. 'Parrot' follows next

Many thanks to the SQLDroid team for the driver and Juan-Manuel Fluxà for demo code on loading databases from Assets to Internal Storage

Hope that helps!

O'Neill Tennis 1.02 - Tennis on a Rotating Space Station

Back in 2014, I made a simulation that modeled throwing a ball in an O'Neill Cylinder and challenged anyone to make a 3D tennis game set on the same rotating space station. Three years later I've answered my own challenge and along the way learned about cross-platform development in Unity. The end result is this:

ONeill Tennis 1.02

You can download for Windows, Mac, or Linux .

The game itself is only moderately fun but I really enjoy just watching the ball move through the air. It's so hypnotically different to motion on earth.

If you want to play around with the project further you are welcome to build off my source code (available here) for any purpose. Changing player speeds, rotation rates, and ball speeds should be as simple as changing a parameter in GameBehavior.cs.

Science EE Wisdom Generator

At the end of the EE journey, I always ask students for advice they would like to pass down to future students. I've complied all their advice together and built this Wisdom Generator for Science EEs.

IB Science EE Wisdom Generator

If you would rather not wait, you can click on the wisdom tab and read through the whole list one-by-one.

IB Physics Example Videos

It's taken about 2 years but I've finally finished a set of IB Physics Example Videos! (131 of them to be exact!)

• IB Physics Example Videos
• Topic 1: Measurement and Uncertainty
• Topic 2: Mechanics
• Topic 3: Thermal Physics
• Topic 4: Waves
• Topic 5: Electricity and Magnetism
• Topic 6: Circular Motion and Gravitation
• Topic 7: Atomic, Nuclear, and Particle Physics
• Topic 8: Energy Production
• Topic 9: Wave Phenomena
• Topic 10: Fields
• Topic 11: Electromagnetic Induction
• Topic 12: Quantum and Nuclear Physics
• Topic D: Astrophysics

The whole process started years before that when I found myself frustrated by how much content there was to discuss/apply/investigate in IB Physics and how little time there was to get it all done. My solution is to take most of the examples that I would normally do in class and record them as example videos for the students to watch before they attempt their homework.

I find that this frees up anywhere from 10-30 minutes per lesson! We have so much time available now that I've restructured my whole lesson plan:

• First 10-25 minutes - Unstructured time for students to address their individual needs:
• Get help from peers or teacher on homework questions or unclear topics
• Read Ahead
• Investigate Extension
• Meet to discuss performance, study skills, etc
• Remainder of the lesson - Lecture, Prac, Investigation, Groupwork, etc on new content
• After the lesson - students watch example videos and attempt homework. They flag the questions they get stuck on and return to the next lesson to get help

Some topics have more examples than others, but every required HL and SL topic (and the HL/SL Astrophysics Option) has some examples. If you think something major is missing let me know but I don't think I'm going to be returning to this video set for a while. I'm on to my next challenge: starting up an IB Computer Science class!

If you are an IB Physics student or teacher feel free to use these example videos as you see fit.

IB Physics Extension

One of the things I like to do in my class is allow students some time at the beginning of the lesson to help each other with their homework questions. The challenge, though, is making sure that students who are on top of things and aren't busy helping others can still be productive during that time.

To that end, I've compiled a collection of IB Physics Extension pages. The idea is that for whatever part of the syllabus your students are currently working on, there's some kind of related, self-guided extension that they could explore. It might be:

• An interesting article on related science
• A really tough problem
• A thought-provoking video or application
• A neat simulation

Just this week I've finally complied enough pages that there should be at least one page for any lesson in the IB Physics course, so no matter what lesson you're on you could always refer a student to the collection of extension topics.

You'll find all the pages here: https://onedrive.live.com/redir?page=view&resid=87532983CCE41649!742&authkey=!AO1VuIbAaVJkrkc

I find that I get the best uptake on this extension if I spend a minute of class time introducing a page or two before students break out into their work.

The collection is still growing so let me know if you spot something neat you think I should add!