I recently purchased a clone Arduino mega 2560 from AliExpress. The clone cost less than a quarter of the official unit (including delivery). As such, the decision seemed like a no-brainer. However, I now realise you should not assume the clone will be identical to the original.
|Figure 1: Genuine Arduino Mega 2560|
My first observation upon opening the package was that the build quality is not as good (refer to Figure 2). Some of the pin headers were quite bent and are shown above after I bent them back into place. This may have occurred during shipping. In addition, the underside of the board is a little untidy.
However, the most surprising observation occurred when I attempted to download a sketch to the Arduino; the connected computer was unable to find it. After reading through a few forums (the most useful forum post was http://forum.arduino.cc/index.php?topic=261375.0) I found that my issue was due to the USB controller on the clone board.
In addition to differences in general build quality, the clones are also cheaper due to a different USB controller chip; the CH340G as opposed to an ATMega16U2 programmed as a USB-to-Serial converter on the original. If you suspect your board may be the same, you can confirm by checking if you can find a chip with CH340G printed on it (refer to Figure 3).
After finding this was the issue, the issue was resolved by following the steps outlined below:
- Download Mac drivers for CH340G from here (Non English site)
- Run the following command in Terminal: sudo nvram boot-args="kext-dev-mode=1”
- Restart system
Once installed, I was able to download sketches to the clone without issue.
NOTE: This may not be an issue if you are using an operating system other than Mac OS X (e.g. Microsoft Windows or Linux).