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A compact and easy soldering modular Smol Slimes / nRFSlime solution with dimensions of 40x28x17mm! If you'd like to learn more about Smol Slimes / nRFSlime, feel free to read the [Smol Slime - SlimeVR Docs](https://docs.slimevr.dev/diy/smol-slime.html). >[!CAUTION] >The current version (1.1) has the following issues: > >- When using the ICM-45686 module from LWKJ, the sensor cannot be detected upon powering up the switch; you’ll need to press the button again to start it properly. >- The button's functionality does not behave as expected. > >Pull Requests are welcome to help fix these issues! ## Description ### PCB The PCB is designed using the **EasyEDA** Pro version, and the repository provides the source files for further modification. For different pre-made sensor modules, I’ve created the following PCBs for different types. However, due to time constraints, only the `VGGALXI` version has been verified. The others should theoretically work. - **`VGGALXI`**: Pin order from bottom to top is `VCC GND GND SDA SCL X INT` (**verified**) - **`VGLAXXI`**: Pin order from bottom to top is `VCC GND SCL SDA X X INT` (**not verified**) - **`KOUNO'S_ICM45`**: Designed for KOUNO's module (**not verified**) ### Case For the case, two versions are provided: - **`Case_v5.stl`**, which requires M2 heat insert nuts. - **`Case_v5_No_Heat_Insert_Nut.stl`**, where screws can be directly fastened into the case. The version with heat insert nuts is more durable. For Bambu Lab printers, pre-configured printing settings are provided here. **https://makerworld.com/zh/models/966982** The case files in the repository are designed to fit **25mm-wide straps** and are also compatible with ReboCap’s quick-release system. If you prefer wider straps, feel free to modify the `.step` source files. ### Firmware The pin positions of this PCB match the default layout in the original project (`SDA-006`, `SCL-008`, `INT-017`), so you can directly flash the firmware provided on the [Smol Slime Docs](https://docs.slimevr.dev/diy/smol-slime.html) without additional changes. ## BOM ### PCB and Assembly The table below shows the components needed for **one tracker**. Note that you’ll also need to purchase one **nRF52840 SuperMini/Dongle** as a receiver. For more details, refer to the Smol Slime page. According to the Discord community, one receiver can pair with approximately **20 trackers** (this hasn’t been fully tested, but it should work for at least 6). | Component | Qty | Notes | | :-----------------------: | :--: | :--------------------------------: | | nRF52840 SuperMini Board | 1 | | | MSK-12D19 Slide Switch | 1 | A legacy switch; other switches may also work | | 3*6*4.3 Tactile Switch (Side) | 1 | Other side tactile switches can also be used | | 401230 / 501230 Battery | 1 | 501230 is recommended; smaller batteries are also fine | | Double-sided tape for battery | 1 | | | Sensor Module | 1 | | | M2*14 Screws | 2 | Used to secure the case | | M2*4.5*3 Heat Insert Nut | 2 | Not needed for the screw-only case version | | 25mm-wide strap | 1 | You can modify the case files for other straps | ### 3D Printing For 3D printing, PETG is recommended, but PLA is also fine. | Component | Qty | Notes | | :-------------: | :--: | :----------------------------------------------------------: | | Lid_v5 | 1 | The lid | | Case_v5 | 1 | Case body that requires heat insert nuts; use `Case_v5_No_Heat_Insert_Nut` if not needed | | Button_Cap_v5 | 1 | Button cap for extending buttons | | Switch_Cap_v5 | 1 | Switch cap for extending switches | | Screw_Holder_v5 | 2 | Screw support pillars; optional but increases durability | ## Assembly Instructions ### Soldering and Assembly - (Optional) Use a probe or other tools to check if the SuperMini, sensor module, etc., are functioning properly. - **Solder the sensor module first**: - Make sure the sensor’s pin order matches the PCB. - Align the pins and secure them by melting solder from the back of the PCB. After soldering, use a multimeter to ensure the circuit is properly connected. - Solder the switch and button. - Make sure the switch is in the OFF position, then solder the battery. - Finally, solder the SuperMini module. - After confirming normal functionality, stick the battery to the back of the PCB using double-sided tape in the designated rectangular area. - Embed the heat insert nut into the Case. - Install the button and switch caps into the case, align the holes, and insert the main body into the case. - Insert the screw support pillars, attach the lid, and fasten the screws. ### Flashing Firmware - Refer to the [Smol Slime Docs](https://docs.slimevr.dev/diy/smol-slime.html) for instructions on flashing firmware. - When using **LWKJ's ICM-45686 module + `VGGALXI` layout**, the firmware configuration `Tracker SuperMini Disabled Disabled` works properly. ## Links - **SlimeVR nRF Receiver Firmware:** https://github.com/SlimeVR/SlimeVR-Tracker-nRF-Receiver - **SlimeVR nRF Tracker Firmware:** https://github.com/SlimeVR/SlimeVR-Tracker-nRF - **Scawanf's PCB R3 on Github:** https://github.com/SlimeVR/SlimeVR-Tracker-nRF-PCB - **Scawanf's PCB R3 on OSHWLab:** https://oshwlab.com/sctanf/slimenrf3 - **SlimeVR Discord:** https://discord.gg/SlimeVR - **Smol Slime Docs:** https://docs.slimevr.dev/diy/smol-slime.html