Students will learn about circuits using the Hummingbird Robotics Kit and Squishy Circuits.

Squishy circuits are circuits made of conductive playdough. Watch the tutorial for an introduction to using Squishy Circuits with Hummingbird or jump past it for a quick reference on connecting items from the Squishy Circuits Kit to the Hummingbird. Please note that this tutorial was originally created with an original Hummingbird kit, but the concepts work with all generations of Hummingbird – original, Duo, or Bit.

Connecting LEDs

You can connect multiple LEDs to a single Hummingbird LED port through conductive playdough. The image to the right demonstrates two ways of connecting LEDs to the Hummingbird. On the left side five LEDs are pressed into a conductive dough sandwich – two disks of conductive dough with insulating dough in between them. The red top disk of dough is connected to the ‘+’ terminal of Hummingbird’s LED port 1. The bottom disk is connected through a black wire to the ‘-‘, or ground, terminal of LED port 1. The LEDs are inserted into the sandwich with the long leg of the LED in the red top disk and the short leg into the bottom disk. In general, you can safely hook up any number of LEDs to a single LED port, but each additional LED will make all LEDs a bit less bright. The LED circuit on the right shows three LEDs hooked up to tri-color LED port 2. A red LED is connected to the ‘R’ terminal, a green LED is connected to the ‘G’ terminal, and a blue LED is connected to ‘B’. The short legs of all three LEDs are inserted into yellow conductive playdough, which is connected through a black wire to the ‘-‘ terminal. This setup allows you to individually control each LED.

Connecting a Buzzer

We’ve found that we can control the piezo-electric buzzer in the Squishy Circuits kit with the Hummingbird’s LED port. To do so, create two blobs conductive dough, put the red wire from the buzzer into one, and hook this blob up to the LED’s ‘+’ terminal. Put the black wire from the buzzer into the other blob and hook it up to the LED’s ‘-‘ terminal. We’ve found that you need to power the port to at least 60% before the buzzer turns on.

Connecting a Playdough Sensor

Did you know that you can use conductive dough as a sensor? You can sense whether someone is pulling a ball of dough apart, twisting it, or squishing it together. To create a playdough sensor, take a single ball of dough and stick a black wire and a red wire into opposite ends of the dough. Connect the black wire to a sensor port’s ‘-‘ terminal. Connect the red wire to the ‘S’ terminal (not the ‘+’ terminal). Now take a resistor (we used this 470 ohm one), and push one lead of the resistor into the ‘+’ terminal of the sensor port. Put the other lead of the resistor into the ‘S’ terminal; there is enough space in the terminal for both the red wire and the resistor’s lead. Then check the sensor value in Snap! – it will change as you pull or twist the playdough, as well as if you break the playdough apart or squish it close together.

More Information

Learn much more about Squishy circuits on their website. Finally, watch Dr. AnnMarie Thomas’ very fun TED talk on Squishy Circuits:

COMPUTER SCIENCE TEACHERS’ ASSOCIATION (CSTA)

CSTA Standards are split into different grade levels: 3-5, 6-8, and 9-10. Working with the Hummingbird Robotics Kit meets multiple standards across these grade-level delegations.
Visit this page for a more detailed explanation of how working with the Hummingbird Robotics Kit applies to meeting CSTA Standards.