Instructions for using the devkit
The devkit boards come with a built in boot loader that enables you to flash new firmware using your mobile device using bluetooth. It's also possible to connect to an ARM debugger.
We already put the latest Freedrum firmware on the boards, so if all you want is to drum away, you just turn it on and connect to your GarageBand or whatever app you're using.
You can either power the Freedrum dev board with a 4.2V LiPo battery, with a USB cable or with a 3.3V power source. Notice that if you use a battery you need to connect it to the battery connector, and if if you use a 3.3V source you need to use the VTG pin.
Check the polarity of the battery carefully before connecting. Reversing it WILL break the board.
Here's a nice little battery that works well with the devkit.
Turn on: push the power button briefly.
Turn off: hold the power button for 5 seconds.
Hard reset: If the device hangs, press Hard-reset.
Power LED: device is on (with battery).
Charging LED: device is charging.
Connecting to Garageband
If you run GarageBand on IOS this is how you connect:
- Start GarageBand.
- Add a drum track.
- From the drum screen, open Settings -> Advanced -> Bluetooth MIDI Devices
- There should be a device called "freedrum" in the list. Just press to connect.
Troubleshooting: Sometimes Bluetooth devices are a bit problematic in IOS. You might need to have IOS "forget" your freedrum if it won't connect. Head over to the system settings, Bluetooth and check if there are any "freedrum" devices listed there. Hit "forget".
Connecting to Android
Android is a bit different than IOS. Below is one way of doing it, tested with G-Stomper
- Connect to Freedrum with nRF Connect
- Start G-Stomper
- You should get a popup when starting, asking if you want to use the connected MIDI device. Press "yes" :-)
- Remap the drum sounds in G-Stomper. By default not all notes that Freedrum outputs are mapped to drum sounds.
Calibration / zeroing
- Calibrate. The gyroscope might need to be calibrated to minimize drifting. Just turn it on and leave it on a flat surface for about 10 seconds without moving it. This should only need to be done once, but if you notice heavy drifting, try it again.
- Zero it. While holding Freedrum in your hand, push the power button briefly. That will "zero" it for the current orientation. That means, the current orientation of Freedrum will represent the middle of your drum kit. These early prototypes are prone to drifting even with a good calibration, so you will need to zero it again from time to time while playing to "reset" the middle position.
Developing your own firmware
How's your thirst for adventure? Unquenchable? Then read on!
Check out our midi lib with a test app here.
This sample does not connect to the on-board MPU6050 sensor, it’s only a demonstration of the Bluetooth MIDI protocol.
To flash a new firmware
- Install nRF Connect on your iOS or Android device.
- Get a firmware update file onto your phone. Get the latest build from us here.
- Startup the dev board holding the on button for at least 5 seconds before releasing it. It now should show up in nRF Connect with the name “DfuTarg”.
- Hit the “Connect” button in nRF Connect.
- Hit “DFU” in nRF Connect and select the zip file with the firmware that you want to flash.
- Wait for about a minute while the device is updated.