Snack Spewing Servo Robot Pal

Backstory

This Snack Spewing desktop robot is based off of the same mechanics that we used to develop our MechaServo MK1 pop-culture replica robot. We developed this half-sized version of that bot to get kids interested in robotics and STEM at Maker Faires and other STEM events since, well, kids love candy. So we packed Tom's head full of gumballs and let kids explore Microsoft MakeCode that was used to turn Tom's head and spit out gumballs while they, well, got gumballs. It was wildly successful, and now it can be yours as well, either at your desk dispensing snackage, or at STEM events drawing sugar-starved children to your exhibit.

Supplemental Info on Materials

The listed materials covers the basic electronics needed, though you can certainly expand upon it by adding a speaker for audio, swapping the Adafruit CRICKIT with an Arduino, etc... but the models were designed around the SG90 (SG92 or MG90, etc) servo motor.

In addition to the listed parts, I also HIGHLY recommend getting the following:

• 1 - 3-inch Lazy Susan ball bearing turntable
• 12 - M3 hex nuts
• 6 - M3 Square nuts
• 6 M3 6mm bolts
• 12 M3 10mm bolts
• 6 M3 washers

Printing Notes

The STL files attached to this project can be printed at.15 or.20 layer heights and are oriented in suggested print bed orientations. I've tested the prints on Prusa MK2, Prusa MK3, and a Zortrax M200.

Regarding supports. Some parts definitely need them, but try to configure the supports on the build plate only if possible, especially for the face where supports within the object could close off the square nut slots built into the model.

You can use either the Torso or the Torso_Cut depending on whether you want the internal mechanisms to be hidden or open to display.

The parts should be printed in, or painted with, the following colors.. but you can use any color combination that makes you happy if you're not going for the full Tom Servo experience:

• Clear: Dome Top, Dome Bottom
• Red: Torso, Face, Snack Funnel, Hat
• Silver: Jaw Top, Jaw Bottom
• White: Shoulder Right, Shoulder Left
• Any Color: Everything else

Assembly Instructions

Video coming soon (ETA March 1, 2020)

Code Samples for Beginners

While we'll be adding Code Samples for Circuit Python for use with the CRICKIT in the appropriate section on March 1, 2020, we also wanted to add some MS MakeCode samples here for beginners who want to ramp their project up quickly or want to use this for STEM education targeting young audiences.

To program your CRICKIT with MakeCode, just plug your CRICKIT into your PC with a USB cable and follow the steps at https://learn.adafruit.com/adafruit-crickit-creative-robotic-interactive-construction-kit/makecode. Once you've done that, you're all set!

Code Sample 1: Pre-Assembly Servo Motor Positioning

This code should be used to set the servo motors to their correct starting positions prior to mounting them into place.

Code Sample 2: Operating Code

Once Tom is assembled, you can use this code as a basis for programming Tom to move his head, then spit out snacks by opening and closing his mouth, then returning to start position.

NOTE: You will need to play around with the servo angles to get the right open and close positions for the mouth and head rotation amounts. I recommend you start from a position where the head is turned to the side, then move to front-facing, open mouth, then shut mouth and return to start. Once you get the servo positions set, make sure you note them in case you ever need to reprogram it.

Additional Notes / FAQ

Q: Can I use this to make a full Tom Servo?

A: Yes, you can use the same process to make your own full animation Tom Servo, with some modifications of course. Namely, you'd need a full model of the barrel torso with mount points for the motor that turns the head like this mount that has holes in the bottom so you can bolt it into the underside of the top of the barrel of a traditional Tom Servo build.

Q. Can I add audio?

A. Sure! Just plug a speaker into the CRICKIT, review the code samples on Adafruit that show how to program audio into your routine, then add a WAV file to the CRICKIT. Of course, you can add audio with Arduino or whatever flavor of controller that catches your fancy.

Q. Can I make this with a Carousel Executive Snack Dispenser like the real Tom Servo has for a head?

A. Sure, same as above, there are ways to modify that part to use here if you want.