Step 12: Proto-Screw Shield
In addition to the circuits created in the previous steps, there are some other components that have to be mounted to the shield.
The servo headers we use are female as we can use double sided male headers to attach the servo cable to the headers. The side closest to the screw terminals is ground.
To attach our input voltage we have the choice of a DC barrel jack or a screw terminal. Either can be used, and having both allows for good flexibility for whatever power source we need to have connected.
We also have a shorting block that can allow the voltage out of the LM317 to be used as the Arduino’s voltage in. While this method does work, we recommend using two power supplies as it will be safer for your Arduino.
There are two test points on the board that will allow you to test the input voltage and the voltage out of the LM317. These are very handy for debugging, as you can plug in a header and use a multimeter to measure the voltages.
There is a large space on the board that we use to place the LM317 and heatsink. Since the design was to be modular with the LM317, we use wires to extend the LM317 to this space. It works quite well as it is easy to remove the LM317, but it remains in place and is able to dissipate heat.