Home  >  Short Range Alerting Systems  >  EFM-100C RS485 Electric Field Mill Kit

High accuracy short range lightning detection from 0 to 24 miles (0 to 38km) with the capability to receive lightning alerts on your cell phone or email while out in the field.

EFM-100C RS485 Electric Field Mill Kit

EFM-100 Sensor with Pole Mount Bracket


• High accuracy lightning detection (0 to 24 miles / 0 to 38km)
• Customizable alarm distances and electric field levels
• Monitors and alerts for weather conditions that precede lightning
• SMS text messaging and E-mail alarm notifications
• Electrical isolation from the field mill to PC or Laptop
• Monitor up to four separate locations per computer
• Inverted Mounting Kit greatly reduces the number of false alarms during heavy precipitation
• Standard RS485 data output with optional fiber optic package
• Aluminum and stainless steel parts throughout for corrosion resistance
• One year parts & labor manufacturers warranty
• Free software updates


Measuring the static electric field generated by thunderclouds the Boltek EFM-100 not only detects nearby lightning but can detect the atmospheric conditions which precede lightning. Electric field data is displayed and graphed on your desktop computer using the included software.

For complete electrical isolation from the field mill outside, the EFM-100 connects to your computer using a fiber optic cable. The EFM-100 features aluminum and stainless steel construction for corrosion resistance, gold plated connectors throughout, and the highest quality ball-bearing brushless dc motor for excellent reliability.

The electric charge contained in a thundercloud also generates an electric field. This field can be measured on the ground.

Electric fields develop wherever there is a difference in electric potential. If the electric field gets high enough you can feel your hair stand on end (if this happens outdoors during a thunderstorm crouch down with your feet together as you are about to be struck by lightning.) An electric field is what attracts your hair to a charged comb or a charged balloon.

Electric field is measured in Volts per meter (3.3 feet) The electric fields which accompany thunderstorms normally measure in the thousands of Volts per meter, usually abbreviated to kV/m.

Lightning is detected as a sudden change in the static electric field.

Parts Included

EFM-100 Electric Field Mill
100 Foot (30m) Cat6 Power/Data Cable
120/220V AC Power Supply
EFA-21 Power / RS485 to USB Module
USB Cable
DIN rail clip for EFA-21 module
6 Attenuator Plugs
Windows Software & Manual

Inverted Mounting Kit:
Inverted mounting mast*, shroud, Inverted EFM-100 cover, Junction box, Silicone grease, and a Pole Mount Bracket or Tripod

Optional fiber optic package includes fiber optic cable, EFA-20 with USB cable, and EFA-10 with DB9 serial cable

*Custom mounting masts available


*Select Power Supply
*Select Power/Data Cable Length
*Select Inverted Mounting Kit
Fiber Optic Cable Package (Optional)

Contact Us