KUWTP Ep. 10 | 28th June 2024 | Configuring the AD5933EBZ board

What doesn’t kill you makes you stronger. We brought our newly acquired items to the lab for our 2nd informal progress check. It was an extremely eventful day at the lab as we managed to successfully configure the core component of our weighing scale – our AD5933EBZ evaluation board, a high precision impedance converter system. However our journey was not a smooth sailing one, as with all journeys.

The first obstacle faced was acquiring a Microsoft Windows system to run the evaluation software on. Unfortunately the Biologist and Chemist are avid subscribers of the apple ecosystem and thus we were stuck. Efforts to download the Windows system on the Macbook to run the evaluation software proved futile. However, the MnT lab came to our rescue and we were able to loan a computer to use YAY! The next obstacle was entirely out of our control – fluctuations in the running of the evaluation program, where sometimes the error notification kept appearing without an obvious cause to it. As #ITprofesssionals, we simply closed the program and opened it again and just like magic, it works HAHAHAHA.

Since our beloved electrician could not make it today, the Biologist and Chemist were left to fend for themselves (was not that bad we seeked alot of help from others LOL thank you MnT staff). The user guide provided by Analog Devices, the manufacturer, was helpful, however as visual learners, we realised that watching a Youtube Video might be more beneficial. To our delight, we discovered this video which aided us tremendously in configuring our AD5933EBZ board! After spending the whole afternoon in the lab, we finally calibrated our board and could move on to using the device on ourselves. Connecting the electrode cables to the electrode pads and our AD5933 board, we took a brave step forward and stuck the electrode cables on ourselves (One small step for man, one giant leap for mankind – Neil Armstrong). JK! It was actually not that dramatic as we could not even feel the tiny current through our body.

Since we are #justagirl, no MnT adventure is complete without an appropriate amount of side quests. Side quest #1 involved us dissecting the headphone jack of the electrode cables to find out what was inside (purely to satisfy our curiosity). To no one’s surprised the inside contained cables! Nonetheless it was fun and entertaining. Side quest #2 was actually pretty important and insightful and was part of our calibration. In order to ensure that we calibrated our board correctly, we tested out different known resistors and ensured that we got the correct value back from the software. However in the midst of testing, we confused ourselves on what each resistor’s value was supposed to be and as reading the colour code on the resistor would be slow and inefficient, we decided to stick each resistor with a cute label (also made us realise how many resistors we coped HAHAHAHA)!

Enjoy the video playlist below of the Biologist and Chemist becoming human toast!

KUWTP Ep. 9 | 27th June 2024 | Arrival of our electrical components

When the going gets tough, the tough go shopping. 3 days after placing our order on Digikey, our items arrived! Can you believe that this whole box is valued at 280SGD+?! Such a small and ordinary box yet its items albeit small cost us so much. Never knew electrical components were so expensive (actually is the AD5933 board carrying the bomb HAHAHAHA).

In true #justagirlfashion, we did an unboxing and of course timelapsed it so you can enjoy the thrills of opening shopee parcels digikey parcel with us! Enjoy the timelapse below ◡̈

KUWTP Ep. 8 | 25th June 2024 | 3D Printing + Soldering

Live Laugh Love. We entered the MnT lab filled with high hopes in finally getting the opportunity to 3D print an object, however our hopes were quickly crushed and we were snapped back to reality. Basically we wanted to print a box (the lunchbox, refer to previous post on what this is!) but it would take 16 hours and cost about $10+ to print which is not very practical and we were advised to buy a box online instead (albeit ugly, this is more practical HAHAHA).

After our failed 3D attempt, we moved onto our next agenda – learn to solder (unfortunately the chemist was sleeping during D&T lessons in secondary school and has never soldered before). Jeremy kindly gave our group a crash course on soldering and briefed us on the safety precautions to note while soldering – mainly the 315°C nozzle and importance of using a fumehood as the fumes released are carcinogenic. We then headed for lunch before properly starting to solder as it was already 1pm.

After lunch we continued soldering and a cool thing we did was connect the LED directly to a button battery and see it light up! ‘Twas was a fruitful day learning to solder ◡̈

KUWTP Ep. 7 | 24th June 2024 | Shopping + Prototyping + Tinkering in Autodesk Fusion

Monday Blues? Who’s she! We started the week off with a bang and chased the Monday blues away with a productive day doing MnT. Our day-long discussion kicked off with our favourite activity – Shopping! However, instead of browsing the catalogue on Shopee or Lazada, we browsed and scrutinised the catalogue of boards and circuit components on Digikey (not sponsored). Comparing different prices and analysing the operating conditions of the components proved to be a tedious yet important task as we did not want to exceed our budget nor did we want to purchase a component with specifications unsuited for our project. For example, when purchasing our load cells, we ensured that the operating force fell within 50kg as too high or low an operating force (e.g. 200kg used for human weighing scales) would result in less reliable results.

After our shopping session concluded and we finished reeling over the hole in our wallet (who knew these tiny electrical components would cost us a bomb!), we got started prototyping with cardboard boxes. This was an important step for us to decide on the measurements of our final product and after much back and forth, we settled on the following dimensions as shown in the picture below. Having a hands-on prototyping session also helped us visualise how our product would look like and the key dimensions we needed to note, which would be helpful when we start sketching in Autodesk Fusion. A notable moment would be how we all sat on the ground and used the cardboard boxes as a makeshift table while discussing instead of using the readily available table in the lounge (see first picture of this post)! #sitonfloorbetter

Before retiring for the day and heading for dinner, we refreshed our memory and skills in Autodesk Fusion by creating a 3D prototype to be printed. We only sketched out the base of the BIA scale, or as we dubbed it the “lunchbox” since it functions similarly to a lunchbox – holding food (circuit) inside. For the platform on which the dog would be standing on, we decided to go with acquiring a solid plank of wood instead of 3D printing out a rectangular board as we fear that a 3D printed plastic board would bend under the weight on a dog and thus cause the weight reading to be inaccurate. This ties back to the title of today’s episode of KUWTP, inspired by a trend on Tiktok (a social media application) where a content creator posts animations of Little John renovating his house with eco-friendly wood veneers and galvanised steel squares (see picture below).

To end the day, we took a trip out of NTU to get dinner at Jurong Point (we eat shihlin chicken way too often, once again not sponsored…) to reward ourselves for accomplishing so many things today! As the only people in hall and of course being notoriously loud, a hilarious incident that happened after we retired for the night was that sichen heard anna refilling her bottle and called out to her, to which teresa heard the entire conversation from inside her room so she came out to say hi too HAHAHAHA. See the pictures below for our little conversation across levels!

KUWTP Ep. 6 | 21st June 2024 | Progress check #1

The early bird catches the worm. We started the day off early and headed to the MnT lab to seek some professional advice (help) from Jeremy about the circuit we would potentially be constructing for our BIA scale. It was a productive morning as he kindly helped clarify the parts we would need to purchase and aided us in better understanding the circuit. Some highlights of the day would probably be the fact that the majority of us thought that Jeremy was a graduated PhD student working in the MnT lab HAHAHAHA but today we learnt that he is actually just a very capable and talented Y2 student! #respect

Our presentation went smoothly (check out our slides under the Development tab!) and we received valuable feedback from the floor on some pointers we can refine on. We also sat in and listened to other group’s presentations which were very informative and engaging. Before our presentation one of our members had to engage in every NTU student’s favourite olympic sport – STAR wars! A canon event for every NTU student would probably be enlisting the help of your friends to help spam a button!

KUWTP Ep. 5 | 20th June 2024 | Preparing for our first progress check

The past few days has been hectic due to our other ongoing commitments (senior’s camp for the upcoming freshman orientation and research attachment meetings) but we still make time for our one true passion and love – MnT! In preparation for our upcoming formal progress check we analysed the components of the circuit obtained from the deconstruction of the BIA scale a few days ago.

As the saying goes – smooth seas never made a skilled sailor, our plans to salvage certain electrical components from circuit obtained from the deconstructed BIA scale fell through as the components were soldered onto the circuit board. This meant that during the de-soldering process, we risked damaging the components and ultimately end up wasting our time. However, this does not mean that our efforts went to waste as we gained a clearer image of what our end product would hypothetically look like. Beforehand, certain members of ours (the Chemistry and Biology HAHAHAHA) had no idea of how small the components actually were and were blown away upon seeing how tiny the impedance analyser was! A component we may be able to salvage would be the load cells for building a weighing scale, however work still has to be done in figuring out the mechanism of a weighing scale and figuring out how to replicate one. Specifically, we would have to scale up the size of the weighing scale to be built to accommodate for larger dog breeds (Odie is a medium sized dog!).

KUWTP Ep. 4 | 18th June 2024 | Deconstructing a BIA scale

In the wee hours of a random Tuesday morning, we had a late night dinner of McDonald’s to fuel us with energy for the long night ahead deconstructing our newly acquired BIA scale. The above pictures depict our last few moments with our new toy, where we took one last final weigh in as well as tested the limits of the scale by having 2 people stand on it at once! Sadly, the scale was unable to detect body composition scale readings for 2 people and our side-quest concluded there. We hypothesise it is likely due to the 2 bodies being unable to form a complete circuit since the BIA scale produces readings by running a small current through the body.

Our adventure commenced at 0138H but we quickly faced a catastrophic boulder. A stuck screw. Due to our lack of experience with tools, we did everything we were not supposed to do: round off the screw by relentlessly turning at the screw. #justagirl After some time, we had no choice but to seek help. Refer to the conversation screenshots for some golden entertainment! They are very much self explanatory HAHAHAHA. Special shout out to Junyi for coming over to do manual labour and completely takeover the deconstruction of our BIA scale. THANK YOU!! (yes, we outsourced it HAHAHAH) A successful night thanks to an overwhelming support from our friends which helped us accomplish a vital step in our journey – taking apart a BIA scale!

Ending off this post with a delightful statement from delightful Dylan, always generously providing constructive comments!

KUWTP Ep. 3 | 17th June 2024 | Public Nuisance

Finally managed to cop an Actxa Sense Smart Scale and the excitement to deconstruct it overpowered Sichen’s social awareness! Sister started to attempt to deconstruct the scale with minimal supplies, and little miss resourceful even started to dig out cards from her wallet to use as a screwdriver! 2 women seated at the table next to us gave us confused stares after we whipped out the BIA scale and started messing around! Truly must be a sight to see – 2 random students fiddling around with a weighing scale in public and even using it in public HAHAHAHA. #justagirl

The Actxa Sense Smart Scale relies on bioelectrical impedance analysis, where naturally occurring electrical currents in one’s body completes the weighing scale’s “circuits” and hence was a perfect model for us to attempt to dissect as it is structurally and functionally similar to the product we intend to make. The structural similarity lies in how we intend to connect 4 electrodes to the dog, just like how there are 4 electrodes in the base of the Actxa Sense Smart Scale.

KUWTP Ep. 2 | 14th June 2024 | Glorified Shopping

After wrapping up our discussion outside the Making and Tinkering (MnT) lab in school, we decided to kickstart our project by doing the most important thing – look for a bioelectrical impedance analysis (BIA) scale otherwise known as a body composition weighing scale in layman terms. As advised by our lab supervisor, we should look for a BIA scale and deconstruct it to understand the different components involved and required in reproducing such a device.

Different BIA scales manufactured by different brands consist of different electrical components as well as equations to churn out the desired output values such as body fat composition and muscle mass percentage. For example from our extensive research done, BIA comprising of AD5933, a high precision impedance converter system solution, produces the most accurate readings for BIA and is commonly used in most devices (Harder et al., 2016). In humans, fluctuation in body composition readings given by different scales is attributable to differing predictive equations used to calibrate the machine. Likewise, research has shown that we need to define predictive equations for body composition based on BIA parameters according to the specific morphological parameters like body size and condition (Yaguiyan‑Colliard et al., 2015). Hence it is of utmost importance for us to accurately tailor and code our product to ensure it accurately reflects the body composition of the dog.

Stemming from STEM backgrounds (pun intended), we believe in hands-on learning and thus decided to visit different electronic stores (Courts, Harvey Norman and even Decathalon) to test out the wide variety of BIA scales available in the market. Prior research concluded that OMRON scales offer one of the most accurate readings (Pribyl et al., 2009) hence we used it as a baseline when comparing the values provided by other scales. However, the OMRON scale is too expensive and will create a hole in our wallet (CN Yang’s wallet byebye funding…) hence we resort to finding the best alternative! Ultimately, after testing out the different scales we failed to find a scale within budget that provided results similar to the ones provided by an OMRON scale, hence our adventure proved unfruitful as we did not buy anything.

BUT don’t fret, stay tuned to find out how we solve this dilemma (we want to save money but still deconstruct a BIA scale because #fun #educational)!

KUWTP Ep. 1 | 14th June 2024 | Risk Assessment

First day back as a trio after the conclusion of our travelling era (live love laugh OLT)! Started off with doing up our risk assessment so we can commence our lab era #justagirl All three RAs submitted got rejected exactly 13 minutes later HAHAHAHA but all’s good because we re-submitted and it got approved after our 2nd try ◡̈