Proof of Concept: Fuel Cube Collector

Today we attached the pulley-belt mechanism to the chassis.

From the side: Pulley belt mechanism attached to the chassis

The slope is 60 degrees. We will probably need less in the finished construction. However proving that it will work with this slope assures us that it will work for less steep ones as well.

For testing purposes the motor was attached directly to the pulley-wheel.

Motor attached to the pulley-wheel

The distance between the pulley-wheels is 19.5cm. The pitch between the big wheels in the front is 23.5cm.

 

Whole robot with the fuel cube collector

Since this is a proof of concept it is very wobbly and very ugly. The extrusions are connected together without much thought and also without cutting them. However after testing we are able to decide, whether to build it anew, a pursue a different idea.

Testing it we found out, that collecting the cubes when they are inserted parallel to the robot works very well and reliably. However trying to collect them when they are diagonal to the robot jams our collector. One solution might be to use a spring-like mechanism with the medical tubing for the front wheels after all.

Also we will need to make sure that the whole slope can be tilted to adjust the height. Additionally we also need to attach the extension of the pulley belt for a proof of concept. The front wheels need to be improved as well.

After testing these things we can move to design and stability.

Constructing the Front of the Fuel Cube Collector

First we built a poly-cord pulley belt, to transport the cubes.

Cube in a proof of concept for the fuel cube collector

We tested this out, by rotating the wheels by hand, thus moving the poly-cord. The result: It works quite alright as soon as the cubes are inside. However the mechanism is unable to pull the cubes in.

That is why we thought about having wheels in the front pulling the cubes in and the pulley belt behind to transport the cubes inside the robot.

Sketch of the general idea

Therefore the next step was to attach wheels in the front of the robot.

We first thought about a mechanism that uses surgical tubing to press the wheels together, and only make them move apart when there is a cube pressing in. This idea is supposed to guarantee that there is always contact between the wheels and the cubes.

We built this by attaching arms to the front. The arms were held back with medical tubing, but could expand outwards when there was cube pressing against them.

Fuel cube collector with wheels on arms pressing against a fuel cube
Close shot of the wheel and the arm. Instead of the medical tubing in the kit, we used a green theraband

However we soon noticed, that it might actually be overly complex. Since our goal is to build everything as simple as possible (it makes it more reliable), we decided to try the obvious and most simple thing. Just attaching the wheels stiffly.

Fuel cube collector with wheels attached stiffly to the frame

For testing purposes, we just drove the wheels directly with motors attached beneath them.

Close shot of the wheel and the motor

We tested this out and it worked marvellously. The cubes are pulled in by just nudging them slightly into the wheels. However once they are inside, they aren’t really aligned. We’ll need to see whether this will be a problem in our pulley belt mechanism later.

Also note that everything is a proof of concept. We will after building most likely disassemble everything and reassemble it cleanly later.

Scoring App

We’re finally launching our Scoring App!

It’ll run on any Android 4.4 or higher and is designed to allow everyone to quickly score points.

You can download the APK here: https://drive.google.com/open?id=1CkP2MGCHxwynBhIxWRhe3Px7lTwz6bui

Or build it yourself by downloading the code from GitHub: https://github.com/Team-Germany-FIRST-Global-2018/FIRST-Global-Scoring-App-2018

As we are not official Google Play developers, you’ll need to activate installing apps from unknown sources. Then just download the linked APK, tap on the file and install!

Functionality that we want to add in the future include an option for saving scores and their summaries, and maybe an option for printing.

See below for more technical details.

With our team having several years of experience with roboters, we already knew how to program Java. The Android API is gratefully quite easy to learn. Especially when you only have one Activity (one window).

Designing the user interface took a bit longer than expected. We started out with something that was functional, to be sure that we had gotten the hang of the API and then continued to think about ways to make the user experience more intuitive. As of now, it should be quite clear, what each button does and fast scoring during a match should not be a problem.

The Android API works by having Buttons trigger a function, which you’ll have to implement in the main class of the Activity. To make sure that we would not have to write functions for every single solar panel, we used an array to save the information about them. Also every time a button is clicked the score is not automatically increased, but rather it is saved whether something has been scored or not.

Then we have a function that uses all the information about what has been scored and what not and calculates a score.

If you want to see the code for yourself (everything might be easier to understand by reading the code) check out our GitHub.

Workshop with Kids – Scratch

You have probably heard of Scratch,  a programming language for kids, that uses blocks to create easy games. Scratch has a cool online editor, so you don’t have to install anything on the computers you’ll use. Additionally it is really easy to understand and kids quickly get the hang of it and start building their own games.

To inpspire younger kids to do fun stuff with technology and science, we have decided to offer them workshops . Our first project was using Scratch. We were really excited that 9 children ages 9-11 came to our workshop and they seemed to have a lot of fun.

So Scratch can be found on scratch.mit.edu. Here you just have to click on the tab “Create”. On the page that now open in the left corner, there is the question mark symbol.  By clicking this, you’ll open a window with tutorials.

We decided to let the children choose their own tutorials, because some of them already knew some Scratch. Some children are quite independent for their age, and will just choose something that fits their needs and ask for help. Others need a bit more guidance, you usually have to tell them exactly what to do.

Afterwards it was quite relaxed. We just went from child to child, asking what they were doing. Don’t be afraid to ask them and show interest in their work! By doing this you can not only help them better, but the kids are always proud to be able to show what they have already done themselves.

Hopefully they’ll be back after the holidays. We’ve already started planning something with the Arduino.

Advisor Call

On Monday we had our first call with our advisors Sebastian and Evelyn. After introductions and some organisational details, we got to discussing robot strategies.

We explained our ideas to them, and showed them our blog.