Hi All,
If possible I would like some help with a circuit I am trying to design please. Unfortunately it blew my nano when I had a PCB made for me and I started connecting it together. I am unsure what I need to include in the circuit to prevent the same thing happening next time. Any help anyone could provide would be greatly appreciated.
The circuit attached includes two 10k thermistors and two 30N06L mosfets to control a nichrome wire and a peltier that would draw 3A max both via PWM outputs from the arduino. It is for a DSLR cooling control I am trying to improve on. The nichrome wire provides mild heating for dew control (+10C) against the lower temperature created by the peltier on the cmos chip of the DSLR. I hope to house the PCB in a small enclosure with an SSD1306 OLED on it to display temperatures and PWM outputs. The code has been tested on an UNO and breadboard and I was previously happy I had both code and circuit right.
On the circuit attached I have not included all the connections for the OLED, other than the 3.3v volt supply from the nano.
Without load (nichrome wire and peltier) connected to the two mosfets, the circuit seems to work fine, however when I connect the wire (which includes a 68 ohm resistor and 26 ohm resistance on the wire) I get what I can best describe as noise on the OLED, in that some of the display seems corrupt on its left hand side. With a load on the peltier mosfet, the nano was damaged.
This leads me to believe that I need some sort of circuit protection between the mosfet circuit and the rest of the circuit, but that's as far I get. My knowledge of electronics is not great as I am sure is apparent from the included circuit.
Thank you in advance for any help anyone can provide, and if there is any more information anyone needs then let me know.
