Tools

Tools & calculators

Free tools that run in your browser. The calculator values below are an example ESP32 sensor node, so change them to match your build.

ToolESP32 pin plannerFlags strapping, flash and ADC2 conflicts on ESP32, S3, C3, C5 and C6, and writes your MicroPython pin map. ToolWill it survive winter?Size a solar panel and battery for the worst month of the year where you live. ToolLoRa repeater height plannerWill the link work, and how high does the repeater need to be? Fresnel zone, earth curve and link budget. ToolRooftop solar yield estimatorDaily and monthly kWh from east, north, west and south roof faces, using your BOM solar exposure. CalculatorBattery lifeHow long a sleepy ESP32 node lasts, and what's eating the charge. CalculatorLoRa airtimeTime on air and charge per packet for any SF, bandwidth and payload. CalculatorVoltage dividerScale a battery voltage to an ADC pin without draining it.

Battery life

mAh
%
Allows for ageing, cold and cutoff voltage
mA
s
µA
min
%/mo
Estimated runtime
–
Average current
–
Usable energy
–
Wakes per day
–
Where the charge goes
AwakeAsleepSelf-discharge

LoRa airtime

Time on air for one packet, using the Semtech SX127x/SX126x formula. Longer airtime means more battery used per message and more chance of collisions on a busy mesh.

bytes
symbols
mA TX
Time on air
–
Symbol time
–
Payload symbols
–
Low data rate optimise
–
Bit rate
–
Charge per packet
–

Each step up in spreading factor roughly doubles airtime, which buys range but costs battery. Check your local MeshCore preset before changing radio settings, because every node on the mesh has to match. To check range and antenna height, use the LoRa repeater height planner.

Voltage divider

Scale a battery voltage down to an ADC pin, and see how much current the divider itself draws.

V
kΩ
kΩ
V
ESP32 at 11 dB attenuation is about 3.1 V
Output voltage
–
Ratio (multiply reading by)
–
Divider current
–
Headroom to ADC limit
–