Author: Yip Wan Ting

solar panels and polycarbonate sheets

Yip Wan Ting Shopping 0 Comment

The last component we needed to settle was the power source. Currently, we have been drawing power directly from the socket, but in order to make the boat travel freely on its own, we would need to give it a kind of portable batteries.

Which required reading of labels I would never have noticed until you were intentionally looking for them. 

We learnt about input and output voltages and currents, how DCs and ACs are used in real life appliances. Turns out, most of our appliances take in the same measurements of current and voltage, and it wasn’t the data we were looking for either… 

After a while we figured out where to look for the data, and then we were able to calculate the total voltages and current needed. 

Tony suggested instead of building a battery out of scratch, we could consider solar panels which would give the boat this rechargeability element, and it was a great idea in that now it was “self-sustainable”, and utilizes the natural energy from the sun!

We found out that this technology actually came from the idea of photosynthesis, and studying the components of chlorophyll — finally, a word that is familiar. 

Its quite interesting to see how biology is applied in the engineering scene. 

So after trying out different positions of the solar panels on the boat, we figured the best way was to place solar panels flat on top of the raft to capture the most sunlight. 

Which also meant we had to get the dimensions of our boat.

We also decided how to attached the observational camera at the bottom, and under Tony’s guidance and experience, he suggested using an acrylic board held by aluminum profiles to extend the camera further below the boat so that the view is not blocked. 

So it was another round of shopping for us, purchasing boards, aluminium profile brackets, longer cables and solar panels.

 

progress update 2

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Presentation Slides 2.0

It was time to update the mentors again. 

Having previously been taught by Alicia, it was good to see her face again, and the very fact she remembered us was heartwarming. (Though hopefully not out of being notorious…) 

Presenting the boat scaffold to Dr Ho was a wonderful moment of glory, slides are attached in the link above for anyone who is curious, because that is also one of our proudest assets: our slides. Most of the presentations were basic, but we decided there needed to be a little bit of personalization to ours. 

And well, slides are my only relevant forte in a making and tinkering course… 

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. 

on and off

Yip Wan Ting Coding, Raspberry Pi 0 Comment

Meanwhile the boys were hustling with the webpage, and it was an insane amount of javascript that being challenged in the languages, at first glance it just seemed like a string of letters and < > / symbols. 

But what blew us away was the back end; which, is what I learnt was a thing. Front end is the webpage you see, and back end is the behind the scenes controls. 

Might have to tilt your head here (yay technology…) but here is the final accomplishment!

inner and outer rings

Yip Wan Ting Making, Tinkering 0 Comment

It was time we tested the pumps… but one thing that stumped us was the connection: it was a center ring, not the typical battery ends of + and -, and we were once again dumbfounded. 

Tony tells us it is called a ‘Barrel Plug’, and a quick google search shows that its quite a ubiquitous plug design!

Justin had to educate us from scratch; linking the concepts of the cathode and anode, we learnt that the center inner ring is usually the positive end, and the outer ring, is the negatively charged end. 

He let us try cool machinery to test out the different charges, and it was so fascinating to see electronics work from theory to reality. 

Maybe also because we are biological science students, so the whole experience was eye-opening and enlightening, albeit a normal occurrence to the mentors in the lab.

Justin also introduced this power supply that lets you vary the voltage and current, and this may sound like common knowledge; but for someone without O level background, I learnt that V= IR… but the way I learnt it was not the conventional: as opposed to seeing it as a solution in a question paper, I saw it as a practical solution to a problem we were actually facing. And it gave a whole new dimension to V = IR.  

we didnt realise we needed this, but Tony was kind enough to lend us 4, and we got about to connecting the pumps to the mosfet board and the RPi…

underwater drone 2.0

Yip Wan Ting Brainstroming 0 Comment

We ended the day with taking reference from the ‘Underwater Drone’, a previous project done by a group of seniors. 

Tony also directed us on what to do next: with aluminum supports, craft a clasp to attach the support to the pipe– and finally, a 3D printing project!

That concluded a to-do list for tomorrow: 

  1. follow up on the swimming pool booking
  2. find out who did the underwater drone project and ask for advice
  3. 3D print a clasp
  4. Procure covers for the PVC pipe so that water does not enter the pipe.

Rendezvousing at the whiteboard, we laid out what was in store for our project:

Cleaned and final version by Zheng Xun

The sun started to set, and so we set off for our homes, ready to complete the agenda the next day.

Not without first having a bit of fun with our pipes…

learning Raspberry Pi and how it works

Yip Wan Ting Raspberry Pi, Tinkering 0 Comment

The next thing was to share knowledge, so everything that the boys learnt by trial and error over the past few weeks: they were giving us a crash course in 1hour. 

First was powering up the cameras and the router. Connecting the wires, plugging into computer, powering up the system…

Accessing the router through the tp-link and the address @ 192.168.1.10x where x refers to the cameras and the NVR (our storage system for all the videos recorded). Once that was done, they taught us how to use Blue Iris and to familiarize ourselves with the interface. 

Then, it was using Raspberry Pi module. Functioning as a miniaturized computer, we reconnected the keyboard, mouse and monitor to the Rpi and lo and behold: 

“Eee why the wallpaper like that one”

Then, the boys introduced to us the bread board and the pins at the side of the RPi. 

Using their previous code, they proceeded to explain line by line, and the numbering system of the pins on the Rpi. 

 

 

and Anita proceeded to make that the desktop wallpaper instead… 

The code programs light bulbs connected in the bread board to blink at certain intervals. So with the lightbulbs and resistors in place, we connected the jumper wires to the board and volia!

NOTHING HAPPENED. 

We were dumbfounded. 

Checking the connections, the code, the lightbulb…we found out about one other important factor: the anode of the bulb.

Basically, LEDs have a long end and a short end.

and if not properly positioned based on current input and output, the LED will not light up.

After troubleshooting and reconfiguring the set up: we nailed it.

The lights blinked in perfect synchrony.

changing the refresh rate of the code, we learnt that the fact that “your eyes have a refresh rate of 20fms” is not exactly accurate, its actually 13.5fms, you’re welcomed. 

cut once measure twice

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The final step was of course to get approval from Tony himself. So after updating him, he gave us the green light! 

And in essence: here is a video montage… sorry the choice of standard background music is limited 🙁

“Eh why the boys make the girls do this kind of work one” 
“Eh why not leh this is so fun… we’re bio students let us live”

Of course, while we were busy with that, the boys were busy with their own struggles: the Raspberry Pi, and figuring out how to code and debug things… but most importantly, impart knowledge to us…

re-calculating…

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Back to the drawing board it was. 

 

Tony told us that we could continue using the materials we procured, so it was time to figure out how much of pipe we could cut. One of the seniors offering to help out kindly did some calculations with us, and the original copy of his workings can be found here: Marine Surveillance (MnT).

He also calculated the amount of weight the PVC pipe could support and plotted a graph, which, long story short — means we could use 1m long pipes to support 4kg worth of weight. 

Here’s some footage of us (starring Jing Rui) attempting to understand the workings… 

the next step was to cut it! 

to be continued