龍卷風

狂風掃葉 葉落歸根

Joule Thief

Posted by doc on March 22, 2021

Here is testing a Joule Thief circuit with a simple oscilloscope.

It can bring the voltage of a battery (with as low as 0.3V left) high enough to light up an LED.

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D-cell

Posted by doc on March 22, 2021

Switching the AA battery with a D-cell. I have changed one of the 100nF ceramic capacitor to a 10nF version. Thus the frequency is now 10Hz instead of 1Hz. So, it can still blink for 10 years. This Energizer Max D-cell has a shelf life of 10 years.

Need to find a housing for it.

The 4 screws holding the circuit board to the battery holder are 1.6mm glasses/watch screws.

I have also pulled away the LED so that it may be afixed somewhere else in its future housing.

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Breadboard

Posted by doc on March 22, 2021

The same circuit on breadboard. This enables me to swap components with different values to test out different configurations. For example, to make the LED blink faster.

Don’t worry, I have tidied it up later, replacing those naked copper connections with proper jumper wires.

And the four jumper wires in the photo connects to a toroid elsewhere.

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Circuit Board

Posted by doc on March 22, 2021

I drew this circuit using Fritzing’s PCB view.

The result:

The problem with this circuit board is the gaps were too narrow. Even with a little moisture, where will be leaking current somewhere. However, with thorough cleaning (with dish washing paste) and drying (with a hot air gun), it worked without a problem. Hot components will make the LED blink faster.

So I made another one:

Still need to wash and dry to get rid of leaking current.

I have also made a templates out of 2mm acrylic sheet. This will let me make more circuit board easily.

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10-year LED Flasher

Posted by doc on March 22, 2021

I got this diagram from https://www.instructables.com/10-Year-LED-Flasher/.

There is another from https://www.hackster.io/simpletronic/10-year-led-flasher-398282 but I tried on breadboard and it didn’t seem to work.

The obvious difference is the lack of a diode 1N5819 in the later.

This circuit is supposed to light an LED bulb for 1/1000th of a second (1mS), every second, for 10 years, using an AA battery.

If you switch the AA battery with a D type battery, which carries 10 times the charge, it may blink up to 100 years, provided that the battery doesn’t deteriorate sooner.

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我操

Posted by doc on February 12, 2021

小明和他爸爸去馬戲團看人走鋼線。他們旁邊坐了一位怪叔叔。

走鋼線的人在鋼線上來回地走著,還幾次差點失去平衡而摔下來。又緊張,又刺激。

隔壁的怪叔叔很入戲,每次險象環生都大叫 “我操!”

走鋼線的人又差點跌倒,他又 “我操!”

小明的爸爸覺得怪叔叔有傷風化,所以對他很不客氣地罵了幾句。

怪叔叔卻歪著腦袋看着小明的爸爸,好像聽不懂。

小明唯有向他爸爸解釋怪叔叔是外國人,聽不懂華語。

小明爸爸:“你懂什麼?他可是會罵粗話的,我就不信他聽不懂。”

小明:“爸爸,人家是喊 WATCHOUT。是小心的意思。”

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天才的鐘

Posted by doc on February 5, 2021

媽媽: 你家飯廳的鐘壞了。

我: 沒有啊! 它只是快了 105 分鐘。

媽媽: 那你為什麼沒有去調準它?

我: 不需要。每次看時間在腦裡減去 105 分鐘就是了。可以保持我的天才數學水平。

媽媽: 🤦🏻‍♀️🤦🏻‍♀️🤦🏻‍♀️

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Home Made Disinfectant

Posted by doc on January 12, 2021

Met a lady in the lift this afternoon. As soon as she entered, she started spraying a bottle of liquid to the air.

I extended my hand towards her and she sprayed some on to my hand. I tried to smell my hand through my mask but no smell came out of it.

She then told me it is a disinfectant that she made herself at home.

“Wow! You make your own disinfectant!” I exclaimed.

She then proceeded to tell me about her water filter at home which can turn ordinary water into disinfectant…

🤦🏻‍♂️

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醫生你很準

Posted by doc on December 28, 2020

婦女有鼻子敏感問題多年,一路來都在我這裡跟進,也已十多年。

今天…

婦女:“醫生,我可以進來量一量血壓嗎?”

醫生:“可以。可以。請坐。”

婦女:“醫生,你真準。”

醫生:“我還沒開始量呢。”

婦女:“不是的,你記得以前時常載我來的朋友嗎?”

醫生:“哦?我記得。怎麼了?”

婦女:“他昨晚去世了。”

醫生:“哦?是嗎?他什麼名字?怎麼了?”

婦女:“腸胃癌末期。”

醫生:“哦。節哀順變吧。根據我的記錄,他最後一次來看我是五年前了,我讀了他的驗血報告,懷疑他有腸胃癌。”

婦女:“是的。那時你對他說過要注意身體健康,如果一直瘦,便血等就要看醫生,並勸他趕快立遺囑。”

醫生:“我記得。這盒紙巾拿去擦眼淚吧。”

婦女:“所以我說你很準。”

醫生:“妳哭得那麼厲害,昨晚又沒睡,血壓上升了。我開些藥,妳回去吃,今晚睡好一點,明天就沒事了。”

婦女:“對了,我左邊乳房好像有硬塊。”

醫生:“先回家吧,別想那麼多。他在天之靈,會多多保佑我們的。過兩天,等你心情穩定了,再來讓我檢查。”

婦女:“好的。”

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2020 年的聖誕節

Posted by doc on December 25, 2020

剛到藥房,便來了一對夫婦,他們的五歲的小女孩兒肚子疼。

女孩活蹦亂跳,根本不像生病的樣子。

“她今早說肚子疼,嘔了一次,應該是食物中毒。” 她媽媽說。

“她昨晚吃了什麼?有瀉肚子嗎?” 我問。

“她昨天生日,吃了很多蛋糕。沒瀉肚子。” 她媽媽答。

“嘩!生日在平安夜!” 我驚呼。

“Doctor, my tummy pain.” 小女孩投訴。

“Where is the pain?” 我問。

“Here, here and here.” 小女孩往肚子上亂指一通。

檢查了一番,除了腸胃蠕動的頻率比正常稍微頻密,沒發現其它異常。

“應該是消化不良,不是食物中毒,也非盲腸。大致上沒問題,這幾天吃清淡一點就好。昨晚的蛋糕是含有芝士的蛋糕吧?” 我問。

“你怎麼知道是芝士蛋糕?” 少婦驚問。

“妳女兒才五歲,消化能力有限。大量服食芝士,未免會消化不良。我開些輕微的藥水為她緩和她的不舒服。以後多加注意。” 我勸道。

“她今早還沒吃東西呢!什麼東西都說不要吃。” 少婦稍微擔憂。

“她昨天的蛋糕還沒消化完畢,妳又想再塞東西進去。妳以為妳女兒是什麼?無底洞?” 我的語氣帶有責備。

“那她現在可以吃什麼?” 少婦急了。

“買支 100-plus,加熱水,當滾水喝,直到胃口恢復就可。” 我安慰道。

“I like 100-plus.” 小女孩突然說。

“We will buy you 100-plus later.” 她爸爸說。

“Do I need to eat medicine? I don’t like medicine.” 小女孩有點不安。

“Only if you want to.” 我答。

“Really?” 她有些高興。

“Oh yes. Only if your tummy pain again.” 我答。

“Then my tummy no pain.” 她馬上答。

她父親猛拍了一下額頭,她母親的表情則有點哭笑不得。

“Happy Birthday and Merry Christmas!” 我祝賀小公主。

“Thank you, Doctor. Merry Christmas, Doctor.” 小公主笑祝。

我和調皮可愛的小公主相視而笑,心有靈犀一點通。

祝大家聖誕快樂。

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