A pair of smart motion tracking sticks that let you play a full drum kit in thin air.
Already have an account? Log in.
To make the experience fit your profile, pick a username and tell us what interests you.
Space Drums are a pair of smart motion tracking sticks that let you play a full drum kit in thin air. Its free (as in freedom), open source, portable to carry in a tiny backpack, and so much fun!
This is the second version of the project. The original Space Drums relied on a smartphone to track your posture and determine which virtual drum you were hitting. In version 2.0, the motion tracking has moved onto the sticks themselves, making the system more compact, self-contained, and responsive.
Before heating up the soldering iron, let's take a quick look at how all the pieces work together.
Space Drums 2.0 is made up of three main parts:
The two sticks communicate with the hub using ESP-NOW. The hub then sends the drum and pedal events to the computer over USB serial, where the audio application plays the appropriate samples.
The drumsticks
Each stick contains two ICM-42688-P motion sensors, along with an MMC5983MA magnetometer and a DRV2605L haptic driver.
When you calibrate the sticks, you point them toward the location where you want the snare to be. That direction becomes the reference point for the virtual drum kit.
From there, the firmware continuously tracks the stick's orientation. When you swing the stick, it detects the swing and determines which virtual drum corresponds to the direction you're pointing.
The drum layout is divided into two rows:
The upper row is selected when the stick is angled above 35 degrees, while the lower row is selected below 35 degrees horizontal playing. Within each row, the stick's yaw determines which drum zone you're pointing toward. Outside the defined angular zones, no drum is triggered.
The firmware uses the motion data to detect a swing and the resulting deceleration. Once a hit is detected, it produces a drum ID and a velocity value. The velocity is represented as a value from 1 to 6 loudness values.
The stick can also trigger its haptic actuator, giving you physical feedback when the virtual hit occurs.
The foot pedals are connected directly to a separate Xiao ESP32-S3, which acts as the receiving hub for both sticks.
The left pedal is connected to GPIO 1 and the right pedal to GPIO 2. The switches are wired between the GPIO pins and ground, with the ESP32's internal pull-ups making the inputs active-low.
The right pedal always acts as the kick drum.
The left pedal can be configured either as a second kick drum or as a hi-hat controller. In hi-hat mode, pressing the pedal closes the hi-hat and releasing it opens it. This assignment is handled by the application (PC/Android), so changing the left pedal's function doesn't require reflashing the hub.
There are three assemblies to print:
1 × Drumstick assembly
2 × Foot-pedal assemblies
Print all the parts before beginning the electronics assembly. The stick enclosure is designed around the custom PCB, with openings for the USB-C connector and power button, so make sure the printed parts are clean and the relevant openings are unobstructed.
Start by placing the Space Drums PCB into the printed stick base.
Use strong 3M double-sided tape to secure the PCB in position. Make sure the board sits correctly in the enclosure and that the USB-C connector lines up with the opening in the printed housing.
The USB-C port is accessible from the outside so you can use it both for charging the battery and uploading new firmware without having to open the stick.
Connect the battery
The stick is powered by a rechargeable battery.
Solder the battery wires to the BAT pads on the PCB, making sure to observe the correct polarity.
Install the power button
Next, solder a momentary switch to the dedicated switch pads on the PCB.
The printed stick housing has a mounting location for this switch, allowing the button to be operated from the outside. I also designed a small 3D-printed cover for the switch, which can be fitted once the switch is in place.
Close the stick
Once the PCB, battery, and switch are installed, fit the printed tip onto the base to complete the drumstick assembly. You'll need 3 m2 screws to connect them together.
Repeat the same process for the second stick.
The foot pedals can be built with adafruit's guide: https://learn.adafruit.com/usb-foot-switch-circuit-python/overview
Then the switches can be connected to the hub esp32 as mentioned before.
Makestreme
Sally Jenkins
AVR
Bryan Souza