Three French Hens in the Box (with Micro:bit)

Surprise (or scare) people with three hens jumping out of a box. A holiday twist with electronics on the classic Jack-in-the-box. These three hens are French, of course.

• 1 milk carton (1 Litre or Quart)
• 3 toilet rolls3 ping pong balls
• 3 sheets of A4/letter paper (stiffer is better)
• 3 micro servo motors
• adhesive tape
• mounting tape
• Blu Tack
• micro:bitTinkercademy GVS Breakout Board for Micro:bit (or similar)

Cut three lids (6 cm by 6cm or 2.36 inches) with a spacing of 1cm or 0.4 inches in between for the hens to pop out from. Remember to leave one end attached to the milk carton as that will serve as a lid. Cut the other end about 1cm or 0.4 inches from the opposite edge so you have a mini-lid for servo motors.

Use mounting tape to attach a servo motor to each lid. Position the rotor such that it can form a latch for each of the lids. Run the servo wires out through the spout – this is easier if you're using a carton with a screw top.

Mark the required length of each toilet roll. We want them to be just a little shorter than the height of the carton (when on its side, of course). You can hold a sharpie stationary on one corner of the box and rotate the toilet roll against the sharpie to get a nice marking line.

Cut slits to the line we marked then flatten and trim to about 1 cm or 0.4 inches all around. Here we're making a little cardboard flange as a base for the french hens.

Cut an access panel along the back of the carton. This will make it easier to reach in and attach toilet rolls to the inside of the carton.

Centre each toilet roll within each lid and tape the bottoms to the inside of the carton. The toilet rolls help ensure each Hen-in-the-box goes straight up and does not get stuck in some other part of the milk carton. Also, tape the top of each cardboard roll to the side of each pocket to keep the toilet rolls centred.

Begin with 2 strips of paper of equal sizes, such as 8.5 inch by 1 inch or 21 cm by 2.5 cm. Tape one end of these strips together, overlapping the ends so that the strips form a right angle.

Snugly fold the lower paper strip over the top one. Next, fold the paper strip that is now the lower later snugly over the paper which is now on top. Continue this process of always folding the lower strip over the top strip, until the entire length of the paper has been folded into a neat little square.

We used 3 pairs (6 strips) for each hen.

Draw a chicken face on each ping pong ball. It helps if you have red, yellow, and black markers. Cut out a comb from red paper and tape it to the top. Finally, attach the hen to each paper spring using Blu Tack.

Roll some clear tape onto itself to make it double-sided and attach it to the bottom of each paper spring. We don't use actual double-sided tape because the added height of the rolled tape makes it easier to attach. Slide each hen into a toilet roll and press down so the tape attaches at the bottom.

Close each lid and attach each servo motor to a micro:bit via a breakout board. Code it up to rotate each servo one by one (press reset to move the servos into a locked position, press the A button to open). Enjoy!