Xiao Daughter Board -> Xiao Module
Solder wires between J1, J2, J3, J4, J5, J6, J7 & J9 of the daughter board to the respective solder tags on the Xiao module. The holes roughly align but will be at a small angle with respect to the boards. As the KiCAD drawing above depicts, the connections are:
J1 - D10
J2 - 5V
J3 - Batt+ Note: An insulated wire needs to pass through the Xiao D2 solder hole to the back of the Xiao
J4 - D1
J5 - SCL
J6 - SDA
J7 - 3V3
J9 - GND
Sensors Soldered Together with Flying Wires
( +, - , SDA , SCA to Daughter Board)
Use double-sided tape to attach the DPS310 PCB to the SDP31 PCB.
3D Print a soldering jig from the Onshape drawing here: Onshape Nose_Jig
Insert the boards and run wires like this:
With all 4 wires run, solder them and trim the wire-ends at the SHT45 PCB:
For testing outside an enclosure - the wires connect from the Sensor-PCBs to the Xiao Daughter Board 1 to 1. Be sure to start at GND, which is a square solder hole (the other three are round):
If installing into the Onshape 3D printed enclosure, insert the Xiao|Daughter Board combo into the middle section of the probe enclosure:
Here is how the PCB's slot into the nose section:
UPDATE August 2023
I found the RF-can of the Xiao board could easily short out connections if not carefully insulated. Therefore I am now insulating the can with Polyimide (Kapton) tape. Picture:
With the daughter board placed and soldered:
Now is a good time to solder-connect the sensors to make sure all is working:
With battery and Ammeter in series (battery is charging via USB):
Here is current draw in normal operation (BT connection established & transmitting data):
Prepare the slide switch by soldering wires and heatshrink covering:
Position switch:
Prepare electronics:
Note: I mechanically secured the wires first with 5-minute epoxy)
Fit sensors to nose:
Note the air-gap above the Temp/Hum sensor. This needs to be filled so the enclosure does not pressurise and affect the barometric sensor (thank you Bernd from TotalVario!). I use Star brite liquid electrical tape:
Pressed some foam into the aforementioned gap to roughly fill it:
Fill the aforementioned gap and allow to cure:
Trim excess with a sharp knife:
Before assembling there are two new tasks I had not anticipated (again thanks Bernd).
The first is to add pitot-like static pressure holes. I have created a jig on Onshape for this. The holes are 0.5mm and there are four of them (just like the static-pressure pitot tube)
.The second is to add Xiao reset connections if wanting to re-program the Xiao. Otherwise, disassembly may be required. There is also a jig for this on Onshape.
.The second is to add Xiao reset connections if wanting to re-program the Xiao. Otherwise, disassembly may be required. There is also a jig for this on Onshape.
I used the pins of an IC socket (machined type, not folded):
Insert electronics:
Start making connections between wires (showing reset wire):
Insulate:
Insert the battery and finalise all connections (remember to have the switch OFF):
Add the brass pins and close up the enclosure.
Power ON via the slide switch. You should hear the startup tones. Connect to BT on your phone and you should then hear a short 'connection successful tone'.
Test with TotalVario.
Programming
To finish, here is a reset push-button switch connected:
To finish, here is a reset push-button switch connected:
