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Posted by doc on August 6, 2021

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9 Russian Songs You´ve Heard And Don´t Know The Name

Posted by doc on May 11, 2021

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Don’t Turn Me On

Posted by doc on May 1, 2021

Also known as ‘Useless Box’.

I have decided to make one on my own.

Bought the box from Daiso, added an Arduino Nano board, some batteries, switches and wires.

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Dog Repeller

Posted by doc on May 1, 2021

This arrived yesterday. Paid MYR 10.90 for it. Didn’t expect it to really work. Tested it with my phone’s ultrasound detector. It was going haywire on the 20.9kHz range.

Tested it on my neighbour’s dogs tonight. They were surprised by it and learnt to stay 10 feet away from me and kept quiet. They were annoyed by it and learnt not to bark. Because every time they bark, I will point at them and turn it on.

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Controlling stuffs using Bluetooth

Posted by doc on April 14, 2021

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Brightness

Posted by doc on April 10, 2021

There is an imbalance of perceived brightness with different colour LED being turned on which requires manual adjustment. For example when red colour is alone, the is relatively dimmer than yellow colour when red and green are on simultaneously. Because the later represents two light sources.

Thus I have fine tuned the later and reduced their power output to around 50% of their original duty cycle. And I did that for the rests too.

Now the brightness from different colours are quite even.

When all three colours are lit, the duty cycle can be reduced even further to 33%.

But there is another problem, the perceived brightness level is not linear in relation to the duty cycle. The relationship is rather a logarithmic one, which can be quite complicated,

Another more accurate way is to derive a method to directly measure the brightness using a lux meter and map out the relationship between power and brightness. One may find out that each colour may have its own graph, and combination of colour may have other graphs.

Even so, lux doesn’t directly reflect on the brightness perceived. A brighter blue LED may appear dimmer than a green one due to subjective perception of human eye.

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Got my vaccination date

Posted by doc on March 26, 2021

Waiting for my vaccine call.

I shall not miss their call.

Got my vaccination appointment.

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Active Noise Cancellation

Posted by doc on March 23, 2021

The best part of the best ANC is to enable you to enjoy the music at its 10% volume in a noisy environment.

Especially the bass.

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Joule Thief simulation

Posted by doc on March 22, 2021

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10 years LED Flasher simulation

Posted by doc on March 22, 2021

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