electro stamping

[bubismark]

hi ,
this is my first serious arduino project and i would like to get some advice .
so i am building an electronic date stamping machine that would sit on my
manual beer labeling machine .
so basically i want to take a motor and connect it to a regular date stamp
and a little color sensor so when ever i reach a certain point on the label it
should trigger the motor and stamp the date on the label .
so here are the questions :
1.is there a Circular motion to a A straight motion kit you recomend ?
2.the wheel that holds all the labels is a little transparent and there are
multiple colors on the label and i want to make it as quick as possible(by quick i mean labeling time)
is there a sensor you recommend ?
any suggestions will be greatly appreciated .

regards

[adafruit_support_mike]

1) A crank-slider mechanism will probably be the easiest way to get the motion you want: https://www.youtube.com/watch?v=ZJuZ92zvgfk

2) Assuming the labels are regularly spaced, you'll have much better luck advancing the tape a fixed distance, then using an optical sensor to check some feature that's easy to identify.. the edge of a label, a hole in the edge of the tape, or something like that. Use the sensor-driven system to fine-tune the position of the tape to eliminate any offsets that accumulate in the fixed-distance advance.