Recycling Corflute in the classroom

I recently managed to get a bunch of large used Corflute sheets and I have been trying to find some purpose for them. Corflute is a really strong material used by Real estate agents (usually) to make promotional boards that go outside open homes etc. Schools and Politicians also use them for their advertising. It is usually printed on one side for an event, and then it is discarded.

The Robocup Search and Rescue layout is made out of tiles (roughly 590mm square) on a large vinyl mat. Since it has to be cut up to be used for the challenge, I thought the corflute would be ideal to make the base for each of the tiles. Each corflute sheet was 1200 x 800 giving me ample space to get two tiles on each sheet.

Cutting corflute is easy as long as you are going with the grain (long parallel framework inside). Use a Stanley knife and you are good to go. If you go against the framework, then you need a fine-toothed handsaw (or a Dremel if you don’t have patience). It is a tough material and using a knife can be difficult, despite what the internet says.

Vinyl and corflute cut to size ready to go

Sticking Vinyl on Corflute is another challenge. Your regular PVA or Liquid nails won’t work. You will need contact adhesive. Look for what your local hardware store provides but for me a spray contact adhesive worked just fine. Make sure you spray it in an open area and take precaution when using it. Use a mask and eyewear.

Once done, finish up the edges of the tiles using some sort of sanding tool like a file or a small sanding attachment with a Dremel (that’s only if your edges are not straight, like mine).

I am planning to use Corflute to make frames / chassis for robots as you can screw motors directly on it. If you have kids, you can even probably make doll houses or shelves for hot wheels with corflute.

Happy building.

Testing the Edison v2.0, Lego Mindstorm EV3 and the mBot

Teaching students the basics of coding using modular components which are relatively easy to ‘put together’(in a lesson) as well as ‘put away’ (tidily in a box) is a daunting task at times for a teacher of Digital Technology. Over the last couple of years, I have been able to test a few of these kit sets and hope to assist people in making an informed choice before buying class sets of these kits. The three that I will review are Edison, Lego Mindstorm EV3 and the mBot.

Firstly, the Edison. I have never used the Edison v1. The first model was launched on Kickstarter, a popular crowdfunding website where they grossed over $100k in 2014. The model did have limited memory and connectivity issues according to the discussion on their blog (however, the company relates it to adjusting sound levels to ‘high’ and removing sound enhancements from your Windows sound function).
The new version is bright orange ( “Edison is bright orange because this colour stimulates enthusiasm and creativity.” – from the Kickstarter blog) and stands out in terms of attention as you can see its motherboard and LED. It runs on 4 AAA batteries and connects via the sound port (3.5mm jack). The packaging is smart and for the very economical price ($70 NZ) I think they have done a good job (Designed in Australia and Made in China).
Connectivity issues were still prevalent when I tried to hook it up for the first time with my Windows 10 computer. I boosted the sound levels up, turned off audio enhancements and it was a while before I actually got it going. Nevertheless, it works!

The device uses Python to run an alternative software IDE as well as a ‘drag and drop’ Chrome extension. The Python version is a good alternative for students who want a challenge while learning basics of programming using Python. It also comes with some templates like Obstacle avoidance and Line follower programs. Personally, I think it’s good value for money considering if comes with a Lego compatibility which is perfect for students who want to build on top of the Edison. However, I am unsure of the connectivity issues(due to the funny sound port connection) and possibly a better design solution incorporating a micro/mini USB port could make this a worthwhile resource.

https://www.youtube.com/watch?v=iFWqxyvgzho

Lego Mindstorm EV3

This is the third in line of the educational kit sets from Lego following on from RCX and NXT. It is definitely an improvement in terms of its processing power as it uses an ARM9 running Linux. The screen pixels have improved along with the ‘drag and drop’ interface for programming the block. There are two versions: the home set and the educational core set. The software provides templates for building certain robots which are interestingly named (R3PTAR, GRIPP3R and so on). Since I had a class set of NXT’s, I decided to buy a couple of the EV3 sets looking at a possible future upgrade. My main concerns were compatibility with NXT kits. So it works out that the sensors are backwards compatible (NXT sensors work with EV3). EV3 sensors don’t work with NXT 2.0 but the motors do. With the programming interface, there are additional blocks like the Ultrasonic sensor which you need to download in order to program the NXT sensors with EV3 software. A bit of messing around before you can basically get both units working in tandem in your class. However, I am enjoying the battery power as it lasts quite a while. Plus the addition of an USB and SD card slot for programs, WiFi and Bluetooth connectivity makes it a very attractive option.

While looking through software interface options for the EV3, I came across LeJOS and Open Roberta Lab(found the links on Wikipedia). I might need to have a play with those interfaces to give students some additional challenges rather than a purely drag and drop interface. LeJOS overrides the firmware to run a Java-based interface on the NXT kit. This ‘flashing’ may cause permanent damage to the unit essentially bricking the device so I would recommend it only for people who have experience in jailbreaking and using other hacking tools. Open Roberta lab ran off the browser but at the time of writing this article, was playing up.
Overall, at $600 NZD ($350USD) at the time of writing this article, I feel the EV3 has its benefits but with a hefty price tag for a learning resource (especially when you need a class set). The sensors and motors are expensive by itself to replace.

mBot
I was highly impressed when I read about the mBot on the Mindkits store (www.mindkits.co.nz for New Zealand buyers). With options of either 2.4G or Bluetooth connectivity, the mBot comes in a blue or pink chassis. Based on the Arduino, the mBot has easy connections to the drive motors straight to the main board (assuming the motor shield is embedded in the design), along with 4 RJ25 connections to sensors. With the base kit, which I got, you can make a line sensor or obstacle detection robot within a couple of minutes. The code was preloaded and it surprised me on how accurately it worked. The Bluetooth version connected seamlessly with devices and works with Apple devices as well, which rarely happens 🙂
The mBlock software which is a drag and drop interface based off Scratch 2.0 is a good starting software for junior students while the senior students who are confident in C could get programming using the Arduino IDE. By selecting the Arduino mode you can instantly see the code in C, and modify it using the Edit with Arduino IDE selection. Very impressive!

The module is very responsive and works instantly and no connectivity issues faced. The only annoying thing I faced was the access to the batteries. Once dead, you have to remove the four hex screws to access the compartment below which isn’t a big issue in the grand scheme of things but surely a design improvement to consider for the next model. However, they have a choice of rechargeable battery which may be the answer to my problem 🙂

I am thinking of using these mBots for entering the Football competition at our local RoboCup challenge(www.robocupjunior.org.nz) coming up. The solid frame and very responsive Arduino model make it an ideal choice for seniors who want to learn to code using C as well as compete in RoboCup.

https://www.youtube.com/watch?v=-hQtdYd5i-Y

Overall the most attractive option I found was the mBot and will also be keen to look into the mRanger (more expensive but more ports). http://www.makeblock.com/mbot-ranger/
Alternatively, you could also look at combining a 3D prototyping unit with Robotics as there are Arduino kits available on eBay(http://www.ebay.com/itm/4WD-Robot-Car-Kit-UNO-Bluetooth-IR-Obstacle-Avoid-Line-Follow-L298N-for-Arduino-/162302756306) which you could possibly modify the chassis by creating your own and this kit would be competitively priced with an opportunity to create and modify design.

With Digital Technology becoming an integral strand in New Zealand curriculum from 2018, kit sets will be a highly valuable resource to teach programming. Looking forward to further development in this area!