GSM Alarm Systems — Remote Sites, No Broadband

SMS and 4G remote switching, alarm triggering, gate control and equipment management.

GSM alarm controllers and relay units enable remote control of equipment via SMS text message or 4G app. Open gates, turn on pumps, switch lights, trigger alarms and monitor sensor inputs — all from your phone, from anywhere. These devices accept a standard SIM card and respond to SMS commands or app controls. Ideal for agricultural automation, remote site management and security alarm integration.

Key features

• SMS & App Control. Send simple SMS commands or use the smartphone app to switch relays on and off remotely.
• Multiple Relay Outputs. 2, 4 or 8 relay outputs for controlling gates, pumps, heaters, lights and alarms independently.
• Sensor Inputs. Connect temperature probes, door contacts, water level sensors and PIR detectors for automated alerts.
• Timer & Schedule. Set automated schedules — turn equipment on/off at specific times without manual intervention.
• Power Failure Alerts. Get instant SMS notification if mains power is lost. Essential for fridges, freezers and livestock systems.
• Low Cost SIM Operation. Uses minimal data — a basic PAYG SIM with £5 credit lasts months. No broadband or WiFi needed.

What SIM and data plan do I need?

GSM alarm controllers work with any standard UK SIM card — EE, Vodafone, O2 or Three. The device is unlocked, so you can bring your own PAYG or contract SIM, or buy a pre-configured one from us. Most controllers use SMS commands and very little data, so a basic PAYG SIM with £5–10 credit typically lasts months.

If you're using the smartphone app for control, expect around 100–500 MB per month depending on how often you check status or trigger relays. For critical sites like cold stores or livestock sheds, dual-SIM models are available — if one network drops, the controller automatically switches to the backup SIM for uninterrupted alerts and control.

Frequently asked questions

Do I need broadband?

No — GSM controllers work entirely on the mobile phone network using SMS and 4G data. Just insert a SIM card and you're ready to go.

How many devices can I control?

Each controller has 2–8 relay outputs, and you can manage multiple controllers from one phone or app if you need to control more equipment.

Can it send me alerts automatically?

Yes — connect sensor inputs like temperature probes or door contacts, and the controller sends SMS alerts when your chosen thresholds are triggered.

How much does it cost to run each month?

Very little — most controllers use only SMS and minimal data, so a basic PAYG SIM with £5–10 credit typically lasts several months.

Is it difficult to set up?

Not at all — insert a SIM, wire your equipment to the relay outputs, and send a simple SMS command or use the app. Most people are up and running in under an hour.

Can I use it outdoors in all weathers?

Yes — weatherproof enclosures are available for outdoor installations, and the units themselves are designed to handle UK conditions year-round.

What happens if the mobile signal drops?

The controller will queue commands and reconnect automatically when signal returns. For critical sites, dual-SIM models can switch between networks for extra reliability.