MavEtJu's Distorted View of the World - Hardware

Seeing IR with digital cameras
Timing is everything

Back to index

Seeing IR with digital cameras

Posted on 2012-08-08 17:00:00
Tags: iPhone, Hardware

In the past I have always been able to see if a infra-red remote control works (or a IR laser :-) by holding a digital camera in front of it and see the flashing of the IR LED on the screen.

However, after having purchased a TVB-Gone (which doesn't seem to work here....), I found out that the camera on the iPhone 4 and iPhone 4S don't pick up the flashing of the IR LED. How annoying. The Samsung Galaxy does still show it.

However, this is only limited to the main camera on the iPhone 4S! The camera on the screen-side still shows the IR flashes on the screen.


No comments | Share on Facebook | Share on Twitter

Timing is everything

Posted on 2012-08-07 08:00:00
Tags: Numbers, Hardware

L1 cache reference ............................. 0.5 ns
Branch mispredict .............................. 5 ns
L2 cache reference ............................. 7 ns
Mutex lock/unlock ............................. 25 ns
Main memory reference ........................ 100 ns
Compress 1K bytes with Zippy ............... 3,000 ns (3 us)
Send 2K bytes over 1 Gbps network ......... 20,000 ns (20 us)
SSD random read .......................... 150,000 ns (150 us)
Read 1 MB sequentially from memory ....... 250,000 ns (250 us)
Round trip within same datacenter ........ 500,000 ns (500 us)
Read 1 MB sequentially from SSD* ....... 1,000,000 ns (1 ms)
Disk seek ............................. 10,000,000 ns (10 ms)
Read 1 MB sequentially from disk ...... 20,000,000 ns (20 ms)
Send packet AU -> Netherlands -> AU .. 320,000,000 ns (320 ms)


No comments | Share on Facebook | Share on Twitter