This project interfaces an Invictus Trainer with a computer or a phone by using encoders and an nRF52840. The video shows a gameplay demo, where you can see what the player sees on the screen to the left of the player.
The project uses the Zephyr RTOS and the nRF Connect SDK. To get started, you must download the nRF Connect SDK which comes with the Zephyr RTOS included: See the installation guide for a how-to
- Clone this project into the root-level folder of a working nRF Connect SDK v2.1.2 installation
Note: In Zephyr terminology, this is a Zephyr workspace application
To build a project, follow the official nRF Connect SDK guide
In short, navigate to the wheelchair-ergometer-game-contrller folder (this may be referred to as the root folder in later parts) and call west build -b nrf52840dk_nrf52840 for building for the nRF52840 DK. Call west build -b adafruit_itsybitsy_nrf52840 to build for the Adafruit ItsyBitsy nRF52840 Express.
NOTE: Sometimes the building might fail for various reasons. If you get error messages that don't make sense to you, try to do a clean rebuild by either deleting the
wheelchair-ergometer-game-controller/project-code/buildfolder and/or callingwest build -p -b adafruit_itsybitsy_nrf52840.
Zephyr does not currently support building for the Adafruit ItsyBitsy nRF52840. You must add this support by copying the adafruit_itsybitsy_nrf52840 folder into ncs/v2.1.2/zephyr/boards/arm. The result should be that adafruit_itsybitsy_nrf52840.dts should be found here: ncs/v2.1.2/zephyr/boards/arm/adafruit_itsybitsy_nrf52840/adafruit_itsybitsy_nrf52840.dts.
If you have not done the copying described above properly, you will get a "board not recognized" warning when you try to build using the
adafruit_itsybitsy_nrf52840target.
Call west build -b nrf52840dk_nrf52840 followed by west flash when the device is plugged into the PC.
The ItsyBitsy comes with the Adafruit UF2 bootloader. This bootloader must be updated as described in the Adafruit nRF52840 guide (note that this guide is for the nRF52840 Feather, but the same applies ItsyBitsy nRF52840). I have only gotten it to work following the command line instructions part of the tutorial.
If the ItsyBitsy ever starts pulsating red, it means something is wrong and you might have to reflash the bootloader firmware as described above. To save you some time, here is the command I usually use:
adafruit-nrfutil.exe --verbose dfu serial --package itsybitsy_nrf52840_express_bootloader-0.7.0_s140_6.1.1.zip --port COM9 -b 115200 --singlebank --touch 1200
Flashing a program is done by dragging and dropping a .uf2-file into the "drive" when it is in boot mode (double tap the RST button). To generate a .uf2 file, make sure to enable CONFIG_BUILD_OUTPUT_UF2=y in the project configuration (prj.conf-file).
To build and flash, perform the following steps:
- In the root folder, call
west build -b adafruit_itsybitsy_nrf52840 - Navigate to
build/zephyrfrom the root folder - Double tap the
RSTbutton on the ItsyBitsy to enable bootloader mode - From
build/zephyr, dragzephyr.uf2into the removable driveITSY840BOOT. - The light on the ItsyBitsy should flicker for a bit before the device disconnects. This means the flash is successful.
If the ItsyBitsy ever starts pulsating red, it means something is wrong and you might have to reflash the bootloader firmware as described in "First Time Setup".
In this project you must choose either CONFIG_HID_MODULE_CONTROLLER_OUTPUT_A=yor CONFIG_HID_MODULE_CONTROLLER_OUTPUT_B=y. Which controller you choose is based on what you want the ergometer to output. I have only used Config A but Config B might be useful for some purposes!
On startup, the device will perform Bluetooth advertisement. It should be found in the pairing menu like you can most normal Bluetooth devices. It is named Wheelchair Ergometer and uses Bluetooth LE (4.0).
| Color | Number of times | Duration | Meaning |
|---|---|---|---|
| Green | 1 | Long | The device successfully booted |
| Blue | 10 | Long | The device is advertising itself as "Wheelchair Ergometer". It should be found when you scan for it on your device. |
| Orange | 2 | Medium | The device is connected but the connection is not secure. |
| Green | 2 | Medium | The device is connected and the connection is secure |
| Red | 5 | Medium | The device failed to connect to its peer |
| Red | 2 | Short | The device was disconnected from its peer |
The device stores which peers it has been paired to. Currently, it can paired to 2 different phones/PCs. This means that the device might not advertise itself (it only does if it has a free slot to store the pairing), or that the device might fail to connect to a paired device in some other way.
To clear these pairing slots, do the following:
- Reset the device by tapping the "RST" button
- Before 5 seconds have passed, double tap the "SW" button
The device should then clear all the pairing slots which frees it up to try pairing again.