- Supported grinders & PCBs
- Required components
- Extract some parts from original board
- Solder PCB top and bottom
- Cleanup PCB
- Install the rest and attach wires
- Upload firmware and test
- Cover PCB with protective coating
- Firmware tune
If you wish to customize this project, or join development, see dev notes.
Warning! Don't buy aqua grinders with horizontal switch placement. Those are very similar, but need different PCB inside
PCB:
PCB:
Warning! Those grinders are out of market and not recommended for use.
PCB:
- v1 board
- v2 development board (has additional interfaces, used by developers to prototype new features)
| - | Name | Comment |
|---|---|---|
| 1 | Grinder mini drill | See links above. |
| 2 | PCB & Components | See links above, acording to your model. If you order PCB first, components second, you will be able to join delivery and save some bucks. |
| 3 | PCB protective coating | Plastik 70 CRC or any other acrylic insulating lacquer. |
| 4 | Male & female 2.8x0.5mm power terminals | Optional. You can solder power wires directly. |
| 5 | 22 AWG wire | Stainless steel / Nichrome / ... (any not too soft), for SMT stencil only. Position paste mask over PCB, via reference holes. |
| 6 | Cheap ST-link/V2 programmer | Only for boards without USB connector. You can also order it at LCSC with other components. |
Note, if you have soldering air gun, it's good idea to order SMT stencil to simplify assembly. Select custom stencil, size 70*50mm & bottom layer only.
Important! If you order SMT stencil, add text note to your order: "make stencil according to paste mask file and don't forget corner holes".
Prior to disassemble, turn grinder on for 5 minutes to run-in brushes. That will make following calibration more stable.
You need:
- Potentiometer.
- Motor terminals (optional).
- Tiac (optional, if Z0409).
We recommend to install all components, except regulating knob. Because on flux cleanup phase, some solvents can wash off speed marks.
PCB bottom (Newacalox & BDCAT):
PCB top (Newacalox & BDCAT):
You should remove the rest of flux, to add protective coating later. We recommend use ultrasonic bath (small ones are cheap).
Now you can install potentiometer, and check everything fits into case. Don't forget to remove flux again.
PCB with speed knob:
PCB in drill body:
WARNING! You MUST unplug power cord prior to firmware upload. Turning power off via grinder switch is not enough. If you plug programmer into computer while AC plug in power socket, your USB interface may be damaged!
- Install VS Code.
- Clone this repo or download as zip archive and unpack somewhere.
- Open folder with project AND after VS Code suggests to install plugins - agree with everything. That should install PlatformIO and all required dependencies.
- Make sure you installed & configured ST-link/V2 drivers:
- Attach USB cable or ST-link/V2 programmer (depends on your board).
- In VS Code, click PlatformIO tab, expand
env:...item with matching MCU/programmer and clickUpload(see image blow). Then wait until complete.
Now you can assemble drill, run self-calibration and try how your "new drill" works.
IMPORTANT. When you turn device on after firmware upload, motor will run at slow speed and will not react on knob. That means, motor calibration required (it's done only once, don't worry).
To run calibration:
- Move knob to zero.
- Move knob shortly up-and-down 3 times (in 3 seconds).
- Wait couple of minutes until magic finishes and motor stops. Be patient.
If everything works as needed, you can go to final step - protect PCB from dust. Or see troubleshooting if something goes wrong.
When you work, drill is actively cooled with air flow. Produced dust can be partially absorbed and cause regulator damage. It's strongly recommended to shield PCB with protective coating.
Warning! Coating should be done after you are 100% sure everything works as expected. You will not be able to solder PCB after that.
Prior to apply coating, don't forget to clean PCB with isopropyl alcohol or acetone. That's important for good adhesion.
You can use special PCB coatings or alternatives. See below.
Such products are "officially" declared as suitable for PCB protection. This can be spray like Plastik 70 CRC, acrylic insulating lacquer, or something else.
If your coater is spray - put it to pepsi cap first and use cosmetic brush to cover PCB. Don't apply spray directly, because you need to keep terminals and knob internals clean.
Usually, lacquers need 3-5 layers for best result.
Note, a lot of ordinary lacquers from your local shop can be ok. BUT, some may have not suitable electric resistance. Don't use untested things, if you are not 100% sure. See more safe alternatives below.
If you have no special PCB chemistry, it may be more convenient to find alternate & more cheap materials in your local shop.
RTV1 non-corrosive silicon glues:
IMPORTANT! You should not use any random silicone glue, because those can contain acid. Advised glues were tested and are neutral.
Disadvantage: all silicone glues need 1 day to dry.
UV gels for nails
Those have more weak adhesion to PCB, than previous recipes. But this method may be more simple/accessible for you. At least, that's better than nothing :).
NOTE. You should NOT use any random gel!
- It should have good adhesion to PCB.
- It should be "top coating" (good durability).
- It should be marked as "soak off" / "no wipe" and so on.
After testing adhesion of different samples, those look nice:
- MIZHSE Rubber Top Coat - preferable.
- UR SUGAR Top Coat - may be more viscous than desired for comfortable work.
Disadvantage: average adhesion, not tested in long term (months and years).
By default, auto-tune tries to do the best, and you should not need manual modifications. But, there are some rare cases, when you may wish to change defaults.
If grinder "oscillates" in some modes - reduce ADRC_SAFETY_SCALE to 0.5. Value should be as max as possible.
Enjoy!