How to Make an Easy DIY Robotic Hand

Your kids can make a robotic hand in a few simple steps with this fun STEM project!

How in the world do you make a Cub Scout robot hand?

I looked for a robotic hand STEM project, and I found plans for what I thought would be a great Cub Scout robot hand. But, the Scouts would have had to use a utility knife to cut notches in plastic straws.

No, thank you! That's just not a skill that I think 3rd grade Bear Cub Scouts have. We have enough to do in den meetings without a trip to the ER for stitches!

Finally, I found a plan for how to make a robot hand!  It looked easy, and with some modifications, it's perfect for our Bears to make.

You'll want to check out these instructions on how to make a bristlebot!

Supplies for the Cub Scout Robot Hand

• Cardstock
• 2 Drinking Straws – Cut into 11 5/8″ pieces and 3 3/8″ pieces.
• 1 Smoothie Straw – Cut a 2 1/2″ piece.
• 1/8″ wide Ribbon – Cut into 5 18″ pieces.
• 1/2′ wide Tape
• Scissors

I tried tracing my hand onto the cardstock, but that didn't work too well! So, I decided that I would create a printable hand for you to use with your den. This will save a lot of time!

Here's what the robot hand template printable looks like. The “joints” are marked to make it easier to fold the fingers.

You can download the hand by entering your email below.

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My straws were flexible, and since you can't use the bendable part, I had to use 2 straws. If yours aren't flexible, you might be able to use only 1 straw.

The measurements don't have to be exact. As long as the straw pieces will fit on the sections of the finger with a little room on each end of the straw, it'll work just fine.

You need a smoothie straw because its opening is much bigger. This makes moving the fingers easier.

You can use yarn for this project, but some of the Scouts may have difficulty threading it through the straws. I found that 1/8″ ribbon like this was much easier to use because it's “stiffer” than yarn.

Your tape needs to be 1/2″ wide. Most of the tape you'll see when you're shopping is 3/4″, but that's too wide. If you want to use the wider tape, you'll have to tear it into strips.

How to Construct a Cub Scout Robot Hand

1. Print the hand on cardstock and cut it out.
2. Fold the fingers along the joint lines.

3. Cut the regular straw into 11 pieces that are approximately 5/8″ long.  Cut 3 pieces that are approximately 3/8″ long.
4. Cut the Smoothie straw in to 2 – 1/2″ pieces.
5. Cut the ribbon into 18″ long pieces. If you want, you can use 5 different colors so that the Bears will know which ribbon controls which finger.
6. Line up 3 pieces of the 5/8″ straw on the table. This will be for one finger.

7. Thread the ribbon through each straw piece. The Scouts should push the straw until it's near the middle of the ribbon.
8. Tear off pieces of tape long enough to go over the straw and wrap around the back of the finger.  Hang them on the edge of the table so that they'll be easy to grab.
9. Carefully put the ribbon on one of the fingers. I started with the index finger. Then tape one straw piece onto each section of the finger. Make sure that the pieces aren't too close together, or the finger won't be able to bend well. The tape should wrap all the way around the finger. I didn't do that, and when my son pulled on one of the ribbons, a straw piece pulled off too.

10. When the pieces are taped onto one finger, fold about 1 1/2″ of the ribbon over the end of the finger and tape it to the back.

11. Repeat steps 6 through 10 for the other finger, except for the pinkie where you'll use the 3/8″ pieces of the straw.

12. When all of the pieces have been taped on, thread all 5 ribbons through the smoothie straw piece. You can do this one at a time or all at once. Tape the smoothie straw piece onto the palm of the hand.

Your Cub Scout robot hand is ready to use! Simply pull on the ribbon of the finger that you want to move.

Don't forget that completing the Robotics adventure will fulfill a requirement for both the 1-2-3 Go! Nova award and the Out of this World Nova award.

Have the kids try some of these signals:

• Thumbs up
• “I love you”
• OK
• Shaka (I've always called this “Hang 10”)

Ask the Scouts to name some of the things that their hands can do that their Cub Scout robot hand can't. I came up with spreading your fingers apart, moving them side to side, and rotating them.

What did your Cub Scouts make their robot hands do? Leave me a comment, and let me know!

Yours in Scouting,
Sherry

P.S. If your Cub Scout really likes robotics, check out these “build your robot” kits!