Place the feedback terminal near a power outlet, take into consideration that the terminal needs to be plugged into the power outlet 24/7. Avoid using extension cords as there can be issues with charging the device the longer it is from the electrical source.
Consider the following aspects when selecting a location:
Can people stop at the terminal and spend a moment giving feedback without blocking others from moving
Is the lighting in the area bright enough
Is there a danger of stepping or tripping on anything
Take care to place the terminal charging cable so it is not stepped on
Is there furniture, plants or other objects that makes it harder to notice the feedback terminal
Pre-purchase:
In a retail store you might want to know if the customer can't find a product or if they would like see a certain product on the shelves
Post-purchase:
After purchasing a product or service, one suggestion is having the feedback terminal located in the area next to the cashier (keeping in mind not to block the flow of movement that would cause a bottleneck)
One could also place the terminal near the exit or door leading to another area