I am working in a project for getting data from a Load Cell, in the project I use a very good Shield built by a very good friend, this shield has a PGA (Programable Gain Amplifier), a Fast ADC chip, and a voltage regulator (to get 5.0 +/- 0.1 V). This shield is over an Arduino Uno, and when I get a command from Serial port I start getting and printing the time and the load cell voltage data each 1 ms, and this is working pretty nice!.
The Arduino is powered by a 120 AC to 5VDC adapter (see the photo attached), this 5 VDC are elevated to ~8 VDC by a
LM2587S-DC-DC-Step-Up-Adjustable-Boost-Power-Supply-Module-Converter-Regulator, see this link
this was because of I wasn't able to get a 120 AC to 8 VDC adapter, and these 8 VDC (I need 8 volts for the 5.0 V regulator mentioned above) are plugged into the jack power conector of the Arduino Uno,
The data from the serial port goes to a USB to Serial Rs232 cable converter, this use a PL2303HX chip (look the link down), and this is conected to the pc with a 3 m USB extension
The problem is that this is the second time that I heard something like an electric short and all the things conected to the Serial port is damaged, I mean the PC USB port, the Serial to USB cable Converter, the Arduino (once) and the Arduino serial port (in the other time).
Looking for what happened I opened the USB to Serial Cable and I saw something like a fingerprint of a spark (see the photos attached), and how you can see this happened in the power line. According to this I guess that this was an overvoltage or an overcurrent in the PC usb port, but the other things like mouse and keyboard didn't fail.
I was wondering if someone could help me to understand what happened, I appreciate any idea.
thanks Thanks for your answers, @Ali_Chen this is a block diagram of my circuit
I don't need exactly 8 volts, but I need 7 V or more for the power jack to power the Arduino, so I choose 8 volts, I use the booster because I couldn't find more than 5V or 12V adapters, and with the 12V regulator of the arduino gets pretty hot, so I prefer to use the booster.
@Ali Chen I saw that too, that the damage was in the power lines, and for that reason I guess that was an over voltage or over current from the pc USB port, but do you think that too?
@slightlynybbled, I had purchase a better supplier USB-TTL cable from SEED, but I buy it from Digikey,
I know this is not as good as Adafruit once, but I am in Colombia and it is really difficult to get this things because I have to pay for shipment and some taxes when it get into the country
excuse me for all the comments in the same answer.