Todays 'How to Build a Robot' video is pretty simple. I'm simply hooking up the i2c serial 16X2 LCD, multiple HC-SR04 ultrasonic sensors (four), and a power indicator LED.
The power indicator LED is real easy. I just hook it up to the breadboard power rails across a 100 ohm resistor and I'm done. The power rail on the breadboard won't get power until the red switch is hit, so this works out perfectly.
The four HC-SR04 ultrasonic sensors are easy to hook up too - just make damn sure you get your power and ground connections right. A few weeks ago I wired one up backwards and the entire sensor got VERY hot. I was surprised I didn't see smoke pouring out. One of the 4 HC-SR04's on this robot didn't work at all, and I think it might be that one.
So each HC-SR04 sensor has a power, ground, TRIG and ECHO pin. That'll be 16 connections total, just for the ultrasonic sensors. As I hook each sensor up, I write down where the pins are going and keep the paper folded up in the robot for future reference.
Now it's time for the i2c LCD. Power and ground again, of course. Then two IO pins. If you are using an Uno or Nano type Arduino, you will need to use A4 and A5 for SCA and SDL. These are the two i2c pins on your Arduino. If you have some other flavor of Arduino, just Google i2c for your device and find out what pins you need to hook up to. If you are using the same i2c LCD as me, there is a small pot on the back you can adjust with a small screwdriver to set the contrast.
Now it's time to make all these systems talk to eachother!