Frequently asked questions

Error: “Cant get reading from DHT” on LCD display
There’s a couple of reasons why you might be getting this message: 1. Incorrect wiring: double check all the wirings. Because the sensor package has ...
Sun, 17 Sep, 2017 at 6:37 PM
In the I2C protocol, are there any reserved addresses?
Yes, there are several addresses that are reserved for special purposes. The following table lists those addresses (table sourced from https://www.i2c-b...
Fri, 6 Oct, 2017 at 8:28 PM
What is the "F" in Serial.println(F("BME280 test"))?
F() is a macro that instructs the compiler to store the string (an array of character bytes) that is passed as a parameter to the MC's flash memory ins...
Sun, 12 Nov, 2017 at 10:31 AM
I2C LCD with the LiquidCrystal_I2C library isn't working as expected
The I2C backpack for LCD displays is a very convenient way to add a character display to your project. The LCD display with the 1602 controller is proba...
Wed, 22 Nov, 2017 at 12:44 PM
What is the difference between analogRead(0) and analogRead(A0)?
The short answer is, none. When you use the analogRead function, “0” and “A0” refer to the same pin, the analog pin 0. So, when you use analogRead, ...
Mon, 27 Nov, 2017 at 1:16 PM
How are the headers of the Arduino Uno different to those of the Mega?
If you are using the Arduino Mega and you are learning the basics of the Arduino, then you are most likely following a tutorial (like my own Arduino Step by...
Mon, 27 Nov, 2017 at 12:59 PM
What are pull-up and pull down resistors
A question I get asked frequently by people new to circuit design is about pull-up and pull down resistors. What is the purpose of a pull-up or pull down r...
Mon, 27 Nov, 2017 at 1:19 PM
Understanding Atmega timers
In the context of AVR micro-controllers, and the  Atmega family in particular, Timers and Timer interrupts is a topic that is often puzzles makers. Alth...
Mon, 27 Nov, 2017 at 1:26 PM
What is male to male jumper wire?
With the Arduino and a breadboard, we use male-male jumper wires. These are wires with a pin sticking out at its two ends. It looks like this: They...
Fri, 1 Dec, 2017 at 12:14 PM
What is the difference between a photoresistor (LDR) and a photodiode?
As the name suggests, a photoresistor is a variable resistor. The resistance of this device changes as the light intensity that hits it changes. This ma...
Mon, 11 Dec, 2017 at 11:49 AM