Testing

countdown and code

Yip Wan Ting Making, Testing 0 Comment

We planned to go to the swimming pool. Especially after a week of correspondence and confirmation with the staff at the SRC — anticipation was at its climax. 

But we had a few problems that remained unsettled… for a start; we had yet to seal the dome with silicon, and silicon takes a day at least to dry… and a lot of skill to apply an even layer without air bubbles… its a whole team effort.

<image of dome, unsealed.>

<the 3-men operation>

or at least, that was how it was for the first dome.

Then we realised we also had to settle placement of the electrical components — the RPi, the wiring, the mosfet channels… which required some hot glue and a long piece of cardboard; recycled from an unwanted piece sitting in a dusty corner in the lab. We took turns settling that part of the hardware, and before we knew it, it was time to set out for the pool. 

The only thing stopping us was, well, Tony. The silicon wasn’t dry, we hadn’t found a good source of battery, and our pumps remained untested. Tony wisely advised us not to go. We were not ready. And it was a good thing we listened too, because the sequence of events that followed thereafter really highlighted that our boat was not yet prepared for the trip. 

Justin found us a lithium battery that had enough watts to power the RPi, but not necessarily the pumps. Without testing the pumps with the new battery, we made a difficult and painful team decision to reschedule the pool “party”… and continue the lab “party”. 

 

On the plus side, we learnt a lot more about planning ahead — other than getting permission early. And also how to solder! 

Learnt a little from DnT back in secondary school, but never really understood the use of it; or went any further than circuits.

This time, we soldered an electrical component and wires, and basically glued it while keeping the circuit “electrically functional” (if, I’m making sense at all…I realise I really am bad at trying to describe or communicate an idea for others to understand me…) 

Justin guided us and demonstrated the first half — and then the challenge was to repeat it on the other side.

 

I was so “skilled” that I burnt the component on the first try and we had to do it again… 

In other news — another skill! “Heat shrinking”! The use of this cool rubber thing that shrinks when exposed to high heat and results in a snug piece of insulation. 

On hindsight, glad to have missed the swimming pool to learn this cool thing you can do in the lab! 

After 4hours it was finally time to test the battery and the pump — and then the second challenge hit: the pumps wouldn’t turn on despite the code having been tested before. Something went wrong, and we were at a loss with what the difference between battery and power source could have done… 

 

Software development in a nutshell: 

Justin even double checked that there was a current running through… 

Being beginners at coding; especially for the websites and using unfamiliar codes like html and java, we were bummed. But thanks to Justin’s investment in our project and his experience in coding, it wasn’t long before he was able to pinpoint the problem, guide us, and then delete all his work to ensure that we could do it on our own — by ourselves. 

And once we finally figured it out, it was about time we called it a day. 

into the water

Yip Wan Ting Testing, Tinkering 0 Comment

While the guys continue to toggle with the code, Anita and I decided to go water rafting. After having written corresponding emails to and fro to the SRC for permission to use the pool, we finally made our way down. It was a long and arduous journey, transporting the bulky boat onto the blue bus under staring eyes and confused bus drivers, getting off at hall 6 and trekking the rest of the way in samsui women fashion to the wadding pool. 

It was a little hard to get any proper documentation of the scene that unfolded as Anita held the boat over her head and I held 2 massive 4inch PVC pipes, but if anything when the box fell apart after our experiment, here’s Anita in the raft.  

 

Skeptical that the box would even float with 2 PVC pipes on each side, we tested the empty box, and it floated magnificently. 

Then after sourcing for some sort of weights, we found bricks and placed them inside, and it still floated, although it was also beginning to sink with the addition of the second brick. 

But upon adding the reinforcing 4inch pipes, the boat was more than capable of handling 2 bricks, with a good 7cm of buoyancy measured from box bottom to the surface of the water.

The problem was, now we had to figure out how heavy the bricks were. Since neither of us ‘gymmed’, the bricks felt like a good 10kg — but turns out, it was only 5.3kg. Oops. [We walked over to the wave, and found a weighing machine. After discovering such a precious find, we transported both bricks — yes a grand total of 10.6kg — to the wave, to and fro. Thankfully we went to the back and found a trolley that the uncle graciously lent us.] 

Needless to say, we were exhausted by the end of the field trip. And so was the cable tires holding our boat together, because just before we boarded the bus again the box fell apart from our raft structure. Anita called the boys down, and we reunited at the bus stop.