I am working on a project using the raspberry pi 3 and the DHT22 sensor. If I plan to connect the sensor directly to the raspberry pi do I need to use a breadboard and 10k ohm resistor?
If you have a bare sensor you need a pull-up resister. 10k will work I'm pretty sure but the device spec is for 5.1k. If you have the sensor on a board then it already has the pull-up resistor. You don't need the board you can just connect the wires. Some heat shrink tubing is good to keep them from shorting with each other. The nice feature of the board is you can plug and unplug different sensors, if you have them.
So that I am clear. All I have is the DHT22 sensor right now , it is not connected to a board, so I can just connect that sensor directly to the raspberry pi and go with that? Just want to be clear.
Go to my website and look at the first article: http://pi.585ranch.com/, it has a picture on how to wire the DHTxx parts. It also has a description of how to use the dtoverlay to get the temperature and humidity data from a DHTxx part and some simple programs to do that.