Hi All. I’m having a bit of an engineering challenge and I figured some people might have creative ideas that aren’t coming to me. 

I’m designing an escape room and I have an Arduino connected to a numpad that, when entered correctly, will trigger an “on solve” sequence that includes some LEDs, an LCD display, an audio output and that is all working great. 

I’d also like a small envelope (2.25in x 3.5in) to slide or eject from the front of the box. 

My original thought was using a servo motor connected to a rack and pinion to act as a linear actuator and push the envelop through a small slit in the front panel. 

Due to poor foresight, my available space is very limited (see photo). I have about 6” x 3.5” of available space left and the envelope is 3.5” long. (Top and front will be covered with a panel in the final assembly). 

I’ve thought about using the servos rotation and an arm to try to push the envelope out but I don’t think I’ll get enough linear motion. 

Other ideas included some type of maglock or drop panel but none of my ideas seem to hold much water when I start mapping them out. 

Any creative suggestions of compact ways for me to get the letter to slide out? 

How to move an envelope, tight enclosure