Arduino Do's and Dont's

I'm currently on the steep learning curve of Arduino.

I've read about a few things that can FRY your Arduino and it's components and wondering if anyone can give me a quick list of Do's and Dont's when designing and building my first project?

Currently I'm just designing a basic project with LED's and sensors.

thanks!

Don't take excessive current from any pin or combination of pins

Don't connect any pin to a voltage beyond its designed voltage which could be 3.3V or 5V depending on the board

Don't forget a current limiting resistor when you connect up LEDs.

wildbill:
Don't forget a current limiting resistor when you connect up LEDs.

Is this required for ALL LED's? and if so how do I know what resistor to use?

10 Ways To Destroy an Arduino is a pretty helpful primer. I think I've done at least three of these.

WARNING WARNING !!!! Aruino Hole Sizes

The many ports for wires and components on an Arduino board can be compromised (made wider).

One project required a resistor at GND. The blue resistor used had thick leads (.84mm .033"). Later, when a header pin (.62mm .024") was inserted into this port, it moved around, a poor connection. The header pin had to be coated with solder to make it seat firmly in the now widened port.

Thinner components, like beige resistors (.22mm .058") and header pins, do not widen the metal in the port.

CONCLUSION: when inserting a thick wire (or component lead), the metal in the port MAY lose its resiliency.

RECOMMENDATION1: Narrow a thick lead with a file before inserting it into a port.
RECOMMENTATION2: Turn off AND remove the battery from a Digital Caliper when not in use, else the caliper will drain the battery remembering the last thing it measured.

(deleted)

skyboyflyboy:
Is this required for ALL LED's? and if so how do I know what resistor to use?

My stance is yes.. ALWAYS use a resistor..
How to calculate.. understand OHMS law.. (or use a calculator!) :stuck_out_tongue:
http://led.linear1.org/1led.wiz
Basically you need to know the following:

  • The forward voltage of your led you want to use
  • The batter source you plan on powering it from
  • The amount of current you want to let the LED have (most accent leds max at around 20mA or so)..
    Here is a calculator for leds in series or parallel:
    http://led.linear1.org/led.wiz

  • Always connect all GNDs together for components/modules
  • Always use a resistor
  • Decoupling is a real thing! Dont ignore it. :slight_smile:
  • Dont connect voltage or components with voltage that exceeds your board (+3.3v or +5v)
  • Any single Arduino pin can only roughly give out 20-40mA per pin.. (and I -think- 200mA for the whole board?) - so you can really power more than an accent LED from an Arduino pin. If you ned to power something with more needs than the Arduino can give.. use the Arduino to drive a transistor that will connect a power source directly to your external component/module

Slight mistake in original posting. "Thinner components, like beige resistors (.22mm .058") and header pins, do not widen the metal in the port." should read "Thinner components, like beige resistors (.58mm .022") and header pins, do not widen the metal in the port.". -- ronart

Unregulated power supplies (wall warts) will output substantially more voltage than their rating, especially under light loads. Connecting a 12v wart to an Arduino Nano (rated for 12v max input) is quite likely to burn it out.