Jumper Pads
On the back of your PCB, you’ll notice jumper pads that can be used to re-route pins, or short connections using a little solder. Don’t touch these unless you know what you’re doing!
| Jumper | Name | Description | |
|---|---|---|---|
| JP1 | GPS Low-Power | Disconnects GPS from power in Sleep Mode | |
| JP2 | GPS RX Switch | Switches GPS RX pin to D3 or TX* | |
| JP3 | GPS TX Switch | Switches GPS TX pin to D4 or RX* | |
| JP4 | LiPo Meter Passthrough | Measures battery with a single resistor | |
| JP5 | LiPo Switch Bypass | Acts as a permanent switch |
*RX and TX refer to ESP8266 pins
Default Connections
chart here
Jumper Descriptions
JP1
This experimental feature disconnects the GPS from power when the ESP8266 enters deep-sleep.
The GPS is connected directly to the 5V line by default, and its not recommended to re-route this deep-sleep mode until tested further.
JP2 & JP3
The ESP8266 is finicky when talking to the GPS, which uses Serial.
The GPS is connected to D3 & D4 by default, which requires SoftwareSerial to communicate - but you re-route the pins to connect directly to the ESP8266 RX & TX pins which use a reliable Hardware Serial connection.
JP4
The Battery Meter feature uses 2 resistors to measure voltage on analog pin A0.
Since the D1 Mini has a built-in pulldown resistor on pin A0 already, the 360K ohm resistor is redundant, and can be bypassed by just shorting the connection.
It’s still included to support other boards which might not have an internal resistor.
JP5
Shorting this jumper will connect the LiPo battery directly to the ESP8266, if you don’t have a physical switch. If you’re powering via USB, you won’t need this feature.