Slamet Hendry


Learning React

In the past month, I have been learning React JS on my own. There are many tutorials on the internet and create-react-app also has hundreds of templates.

But I could not find one that specifically do what I wanted, so I had to do a lot of trial and error. How hard can it be? Harder than I thought, but eventually I got it working. 😎

Maybe there is another fellow learner out there who has the same need: web app that is protected by login and is multi-language. So I shared my codebase for others to copy and use as a starter template. The codebase is on my GitHub repo.

I hope it is useful.


Huawei Watch Fit conclusion

I have been using the Watch Fit for about seven months and this is my final follow up on it. To get some context, you can read the second review and the first review.

Recently I found another issue (beside the GPS, which I wrote previously). It lost my exercise / run data a few times already in the past few months. I finished my run and checked my stat, but when I sync'ed and checked on the mobile app, the stat was not there. I checked on the device and indeed the data was gone. This happened a few times. I am not concerned about my stat, but I am bothered that it cannot reliably save data, which to me is a basic reliability requirement.

All in all, for its price, the Watch Fit is an attractive offer.

Style-wise, it looks somewhat like Apple Watch which is not my favourite style, but Huawei Watch Fit is not as wide and somehow strikes me as better looking than Apple Watch. It is also very light.

The user interface / UI is brilliant. I did not appreciate the UI much until a couple of days ago when I tried the Garmin Forerunner 45. I will write about the Forerunner 45 in another opportunity, but in short Watch Fit UI is superior. Its on-screen control is easy to use in so many ways.

The mobile app is easy to use and focused on functions that I care and no more. 👍🏼

In conclusion, the Watch Fit is my first wearable and I enjoy using it. If I lose it, would I replace it with the same model? No. I would get their next iteration or a different product.


Kanji Dōjō

I made an app to practise writing Japanese kanji. Please check it out. Or if you know someone who is studying Japanese, please share it.


Huawei Watch Fit follow up review

I have been using the Watch Fit for sometime now, so this is a follow up to my initial review.

The watch strap is made of soft rubber; it is really nice. However, unlike Garmin Vivosmart and Xiao Mi Band that use a clipping mechanism, Watch Fit uses traditional buckle mechanism. And for hours and hours typing on keyboard, traditional buckle does not sit too well for my typing comfort. Thus during the day, I stay with my mechanical watch which does not use traditional buckle.

So I only wear it at night and for running.

Sleep tracking turns out to be interesting. Whenever I feel lacking energy, the sleep tracker confirms that I did not get a lot of “deep sleep” the night before.

The Watch Fit does not have any setting to turn GPS on or off, which I thought odd initially. But then I realise that it is actually set by choosing the exercise mode. Initially I thought: why does it have “Running Outdoor” and “Running Indoor” modes? The answer, obviously, “outdoor” mode turns on GPS. Likewise with other outdoor exercises in the list.

Acquiring GPS signal is a bit slow most of the times. I don't know if this is a factor of my neighbourhood's location or not. To date, I have not used it elsewhere.

The GPS distance measurement is not consistent. This is a bit annoying if I run a fixed route. I now understand why there is a wide price range for GPS-enabled fitness trackers. If precision is important for your regime, I can see why you will want to buy high end fitness tracking models.

As for my current need, I am learning to not worry about it.

Battery life is as advertised by Huawei. When it is down to 10%, it will alert me. The recharge time is fast. It takes 25 minutes from 10% to 80%. Give it 10 more minutes and it reaches 90%.

The system has been stable for me. I did not run into any issue at all, but Huawei updated the firmware twice already for minor enhancements.

In closing, if you want GPS and not too demanding about it, Huawei Watch Fit is a good value for casual fitness tracking.

Have fun with your exercise.



“Everyone knows that debugging is twice as hard as writing a program in the first place. So if you’re as clever as you can be when you write it, how will you ever debug it?”

~ Brian Kernighan

#quotes #design

Four Ps

“We do not need to change the four Ps (Product, Price, Promotion, Place) because of digital. We need to understand that the constituent elements that make up the four Ps have changed – will continue to change – as time moves on.”

~ Mark Ritson

#quotes #design

Huawei Watch Fit initial review

My Casio W-753 watch has been my running buddy for 8 years and it still works fine, but recently I have become curious enough for a fitness tracker.

I wanted something small like Garmin Vivosmart 4, Xiao Mi Band 5, Fitbit Inspire 2 or Fitbit Charge 4. I tried each of them on my wrist, but in the end I ended up buying the bigger Huawei Watch Fit for overall fit on the wrist and legibility. It happens to look good, too.

Lesson learned: Online shopping is all the rage indeed, but physical store presence helps a lot.

The Watch Fit's dial / face can be changed in the setting (and it is also possible to download more styles). The physical button on the right side opens up the menu system and the rest is handled on-screen. The screen is touch sensitive with the user interface focused around swiping, scrolling, and tapping the on-screen button. While exercising, the screen responds decently to sweaty finger swiping to see different modes, if needed.

It tracks heart rate, SpO2, stress, menstrual cycle, sleep, etc. Despite being feature rich, I think the user interface is decent.

I have only used it for one 10K run. The GPS measurement came out different from what I once tracked on my phone. A run route that my phone said 2.1 km registered only about 2 km on the Watch Fit. Not sure if the on-board GPS can / should be tuned using the phone first.

One nitpick: This being my first fitness tracker, I was dismayed that I must download the Huawei Health app onto my phone and pair it with the Watch Fit, before I could set it up to use it. The store staff told me that I could disconnect and delete the app afterward.

I wanted a fitness tracker so I could conveniently understand my heart rate while running, so I was not planning to connect it to Huawei server. I could not see any technical reason why a registration is a technical pre-requisite to operate the tracker. The company just wants to get data. Unfortunately, there was no way around it, so I downloaded the Huawei Health app and connected the device. (Huawei provides options in the setting to turn a few things off.)

And the app is decent. For fitness tracker users, the data analytics out of the app is what gives the benefit. I am still a newbie at this; maybe I can warm up to this concept slowly. So I have not deleted the app, yet.

So far, so good! Overall, there is a lot to like in the Huawei Watch Fit.

Update 1: I found out that the app shows the map of the run route and the map looks correct. And on my second run, I ran my usual 1 km loop that I know well and the distance on the Watch Fit seems to be correct.

Update 2: Third run – I retraced my 2.1 km route and the Watch Fit indicated that it is indeed around 2.1 km. I suppose that is good, but I do not know what I did to have improved its accuracy, other than keep using it.



“Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.”

~ Antoine de Saint-Exupéry, Airman's Odyssey

#design #quotes

Should I buy a camera?

With computational photography, smartphone these days produces seemingly good looking photographs. Major phone brands try to convince you that their phone cameras can produce pictures that are as appealing as those coming out of cameras with professional specs.

Do we need a dedicated camera?

Given that the best camera is the one you have with you, I have been considering whether I will stick it out with just my smartphone camera (which I always have with me) or whether I should replace my dedicated camera.

I had not made up my mind completely yet, but my beloved Pentax K200D camera saw less and less action in recent years to the point that I even left it at home for recent holiday trips. So earlier this year I gave it away, along with the Sigma DC HSM 30mm/f1.4 lens that has always accompanied the K200D, to a friend who I know can make better use of them than me.

I saw pictures taken from the latest smartphone cameras and there were many cases where they were really good, but there were many other cases where they were not up to my standard. I still was not convinced I can survive with just smartphone camera.

About a couple of months ago I bought a new smartphone and last weekend I took some pictures at a dinner. I forgot about them until today as I browsed through the photographs and I thought: not bad, not bad at all.

Amongst the pictures that came out good, I knew it would be better if I work the crop factor a bit. Sure enough, after cropping, the image came out cool.

However, during the process I noticed something that people may miss, if they do not have experience shooting with dedicated camera + good optics.

The computational bokeh from the smartphone fails miserably during the transition from in-focus to out-of-focus area. Give a close attention to the boundary of the neck and the hand.

Interestingly, although not a complete surprise, the computational algorithm can fail to kick in when it got confused.

On the next picture, pay attention to the area between the hand and the neck and the small area between the thumb and the other fingers: the algorithm missed them and did not generate the bokeh effect.

I cannot compare the same scenario taken with a dedicated camera, but here is a flower taken with the Pentax+Sigma at f1.7.

Bokeh represents areas where physically, light enters the lens as out of focus, indiscriminate to the fact it is a small area or large area. And in the real world, out-of-focus is also dependent on physical distance, so the bokeh effect varies based on the location of the objects.

I am happy with my smartphone camera, but this post shows that for certain kind of images that I am accustomed to make, I should buy a camera.