Important: Throughout this tutorial, we assume you have at least a basic knowledge of soldering. Reach out to us if you need more assistance.

Soldering Instructions

Step 1: Take everything out of the package and make sure all parts are there.

Step 2: Solder GPS module

1. Use the wires that have a white JST connector on one side.

2. Cut wires to about 2 inches in length from the JST header.

3. Strip all 4 wires (22 gauge) so that about 1/8 inch of wire is exposed.

4. Twist strands of  each exposed wire to make it easier to insert to holes.

6. Solder the black (GND) wire to the GND pin on the microcontroller.

7. Solder the red (VCC) wire to the 3V3 pin on the microcontroller.

8. Solder the white wire (GPS TX) to Pin 7 (microcontroller RX).

9. Solder the green wire (GPS RX) to Pin 6 (microcontroller TX).

At this point, 4 wires should be soldered to the microcontroller:

1. GPS GND to microcontroller GND
2. GPS 3V3 to microcontroller 3V3
3. GPS TX (white) to microcontroller RX (Pin 7)
4. GPS RX (green) to microcontroller TX (Pin 6)

Important: If the TX (Pin 6) and RX (Pin 7) pins are soldered backwards (TX->TX and RX->RX, which is incorrect), the GPS will not communicate correctly with the microcontroller.

To fit the module into the case, these GPS wires need to be soldered to the back of the microcontroller. Inserting the wires through the holes from the back makes it easier to solder and also makes a stronger connection.

Insert the wires through the holes from the back of the microcontroller. Solder the exposed tips of the wires on the top of the microcontroller, as shown. The video on this page might be useful showing this.

Step 3: Solder Battery Wires

Important: Some included battery wires have 2 connectors on them: a JST connector and a Molex connector. The correct side is the JST connector. You can test which one is the correct one by inserting the battery into it.

If the battery wires you received do not have both connectors on it, do not cut it skip to step 2.

1. Cut the wires close to the Molex (the incorrect) header, so that the JST (the correct) header has the whole length of both wires attached to it.

2. Cut the red (power) wire in half, so that half of the wire is still connected to the JST connector. Don't cut the ground (black) side.

3. Strip both wires so that about 1/8 inch of wire is exposed.

4. Using the red power wire that you just cut from the battery connector wires, strip both sides, so that about 1/8 inch of wire is exposed.

Tip: Tin the tips of the exposed wires

5. Solder one of the red wires to the middle pin of the switch.

6. Solder the other red wire to one of the edge pins of the switch.

7. On the back of the microcontroller, there are 2 exposed pads that are labeled “BAT+” and “-”. Tin these pads on the microcontroller.

8. Solder the black (ground) battery connector wire to the exposed pad that is labeled “-”. For reference, it is the one closest to the USB-C port.

9. Solder the red (power) wire (the other end of which should be connected to the switch) to the pad labeled “BAT+”.

Note: It can be helpful for fitting the module into the case to orient the wires with the wires directed inward (see picture)

10. Soldering is complete!

Assembly Instructions:

Important: Install the GPS first. The GPS module will be difficult to install if the microcontroller is installed first.

1. Slide the GPS module in at a low angle. Make sure the ceramic antenna is oriented against the top of the case (the label of the GPS module should be visible when installing).

Note: There will be some play (moving) when the GPS module is placed correctly. This was a design decision to facilitate inserting the module into the case.

2. Insert the microcontroller so that the USB port fits into the slot.

Important: Make sure the wires do not get caught underneath the microcontroller as you insert the microcontroller.

3. Push until you hear a click. The click means the clips on the case have engaged.

4. Remove the adhesive cover from the foam piece and attach it to one side of the battery.

5. Place the battery in the case, with the foam oriented so that one side of the foam is stuck to the battery and the other side of the foam is against with the GPS module. The purpose of this foam is to protect the battery from the rest of the components in the module.

6. Push the switch into the switch slot. Note that this may require some force, but be careful not to push too hard, or you might break the ridges on the case that hold the switch in place.

7. Place the top part of the case onto the bottom case.

8. Assembly is finished!