Mighty Mule FM231 Wireless Driveway Alarm
- Electromagnetic sensor detects vehicles, not people or animals
- Up to 400 ft wireless range to the receiver
- Indoor receiver with audible chime
- 2 AA batteries (not included) power the sensor
- Low battery indicator on sensor and receiver
- Expandable with extra receivers (FRM231-R)
- 12 month limited warranty
Updated 25 days ago · Based on the Amazon listing and published specifications, not hands-on testing.
A dependable driveway alert for long drives and rural property that triggers on vehicles rather than wildlife. The transmitter needs shelter from sprinklers and heavy rain, and batteries are extra.
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ASIN: B003765W0WModel: FM231Category: Home Security Systems
Overview
Burying the sensor beside the driveway is the main install step: the Mighty Mule alarm senses large metal objects like cars and sends a signal to an indoor receiver that chimes. No wiring is needed.
Electromagnetic detection reacts to cars rather than people or animals, cutting false alarms. The long wireless range covers rural drives and businesses. The transmitter should be shielded from sprinklers and heavy rain, and batteries are not included.
Who it's for
Rural homes, farms and businesses with long drives get early warning of visitors. People wanting to watch for pedestrians or see who arrives need a camera system.
Pros and cons
- Ignores people and animals
- Long wireless range
- No wiring needed
- Expandable with more receivers
- Batteries not included
- Transmitter needs rain protection
- Detects vehicles only
Performance notes
Detection works by the sensor reading changes in the magnetic field as large metal objects pass, which ignores animals and walkers. Signal reach depends on the path between transmitter and receiver. Installing batteries at the site lets the sensor learn its surroundings.
Specifications
| Brand | Mighty Mule |
|---|---|
| Model | FM231 |
| Dimensions & fit | |
| Item weight | 1.5 pounds |
| Capacity & performance | |
| Maximum Range | Up to 400 ft wireless |
| Power & efficiency | |
| Power source | 2 AA batteries (not included) for sensor |
| Compatibility & installation | |
| Installation Type | Wireless DIY, buried sensor |
| Warranty & support | |
| Warranty Description | Limited 12 month manufacturer warranty |
| Other details | |
| Sensor Technology | Electromagnetic vehicle detection |
| Alert Type | Audible chime |
| Number of items | Transmitter, sensor, receiver, transformer, mounting post, instruction manual |
Frequently asked questions
Will the Mighty Mule FM231 work with additional receivers?
Yes. You can add more indoor receivers, sold separately as FRM231-R, for coverage in other areas.
Will the Mighty Mule FM231 go off for deer or people?
It uses an electromagnetic sensor that detects large metal objects like cars, which reduces false alarms from animals or pedestrians.
Where should I put batteries in the FM231 sensor?
Install the batteries near the installation site so the sensor can learn the area. Installing them in the house may cause it to work improperly.
Is the FM231 transmitter waterproof?
It is weather resistant, but the description advises protecting it from direct sprinklers and heavy rain.