What DMC size should I use?
Have you ever wondered how big DMC code you need so that majority of people will be able to read it with mobile phone from desired distance? If yes, that read forward..
I made a simple test with two popular cell phones iPhone 4S and Samsung Galaxy Note4. I printed different sizes of DMCs with black-white printer. Later I measured the distance from which the DMC reader program could successfully read the code.
I used application called i-nigma which can be found on Google Playstore and App Store.
As already describe on other posts about data matrix code I will focus on module size which is the smallest building block of DMC and is defining DMC resolution.
Graphs below represent correspondence between the DMC module size and data matrix code scanner reading distance.
As you can see both mobile phones did their job quite similar. A bit better performance was reached with Samsung Galaxy Note4.
Slope coefficient calculated from measurements is around 21,4. As test was done on DMCs with best contrast and in good illuminated space, I would propose that for safe calculation you use coefficient around 20.
DMC size conclusion is seen below.
Lets focus on DMC code with encoded sequence “datamartixcode.net” (picture below). We see that this is encoded into DMC with 18×18 modules. How big DMC do we need so that people will be able to read it with mobile phones from distance of 2 meters?
First lets calculate module size…
Module size in mm = 200 mm / 20 = 10 mm.
Lets calculate the DMC size…
DMC size in mm = 10 mm * 18 = 180 mm. Meaning that we need a DMC that is 180mm height and 180mm width.