Here is a comprehensive guide to installing the hardware components that make up a MaxMon installation. If you are new to MaxMon it is worth first checking out How MaxMon works.


There are three main components in a MaxMon system: an Android phone, one or more Quatropus units and a number of transducers connected to the phone via the Quatropus units. An Android app runs on the phone, controlling the system. Transducers are either sensors (measure things) or actuators (control things).


Up to 4 transducers can be connected via standard cat-5e cables to a Quatropus. Some transducers require further wired or wireless connections, for example the Sensor-C2 requires wired connections to separate float and proximity sensors.

Planning your installation

Planning a MaxMon installation is all about where to place the components and where to run cables, taking into account tidiness and limitations on cable lengths (as documented in the technical specifications). In some cases it's as simple as leaving the MaxMon components on a table, plugged into mains power, in some cases it's a little more complicated.

Our recommended approach to planning is to begin by choosing the best location for the phone. This will then suggest the best locations for the Quatropus units, which must be within 2-5m of the phone. This in turn will suggest the best locations for the transducers connected to the Quatropus units, which vary widely in their cabling requirements (but generally support longer cables and are thefore more flexible re location). As with all such planning exercises there will probably be some iterating back and forth before deciding on the final installation.

Step 1: Choose a location for the phone

Factors which affect the location of the Android phone include:

  • Control panel - the phone is used as the control panel for the MaxMon system, so it should be easily accessible.
  • Wifi and/or mobile networking - the phone requires a reliable connection to WiFi and/or mobile networks. In some properties this can require mounting the phone in unusual locations, such as using suction cradles (designed for a car) to mount it to a window.
  • Quatropus - the phone must be connected to the Quatropus units. For the older Quatropus1 this means a ≤2m USB cable. The newer Quatropus2 communicates with the phone via Bluetooth (≤5m line of sight, no intervening metal) but can also supply power to the phone (see below) via a ≤2m USB cable.
  • Power - the phone requires a 5V micro-USB connection to stay charged. This can be provided from (a) any compatible mains- or battery-derived phone charger, or (b) via a USB cable from a powered Quatropus unit, or (c) via a USB cable from a powered Sensor-B transducer. USB cables used to charge the phone should be ≤2m in length.
  • Camera - in many MaxMon systems the phone is mounted so that its rear-facing camera points at the interior of a monitored property, so it can take photos. This is often achieved using off-the-shelf car phone cradles. Note that to use the the phone as the MaxMon control panel it will need to be picked up and turned round. Some MaxMon owners use more expensive phones with both front- and rear-facing cameras, to take photos in both directions.

These factors often, but not always, lead to locating the phone in a relatively central location within a monitored property. Once you have an idea where you might want to locate the phone, proceed to Step 2: choosing a location for your Quatropus units.

Step 2: Choose a location for the Quatropus

Factors which affect the location of your Quatropus unit(s) include:

  • Phone - proximity to the Android phone. A Quatropus1, or a Quatropus2 providing power to the phone, needs to be connected to the phone via a ≤2m USB cable. Quatropus2 units that are only connected to the phone via Bluetooth must be ≤5m from the phone with no intervening metal. Nearby pumps or motors can also interfere with Bluetooth.
  • Power - each Quatropus requires a 5V micro-USB power connection. The most common configuration is to use the charger that came with the Android phone, with a USB cable to relay power on from the Quatropus to the phone (in other words the Quatropus is connected between the phone and its charger). But the Quatropus can alternatively be powered by any 5V micro-USB charger. Still another alternative is to power the Quatropus from a Sensor-B transducer, via a ≤2m USB cable.
  • Transducers - each Quatropus unit can connect to up to 4 transducers using standard cat5e cables (1m cat5e cables are supplied as standard). Most transducers support up to 10m cate5e cables, although voltmeter-based transducers only support up to 2m cat5e cables - see per-transducer technical specifications for details. Using higher quality but more expensive cat6 or cat7 cables can considerably extend these lengths. We recommend using super-flat cat5e|6|7 cables as they are flexible and easy to lay under carpets.
  • Tidiness - Quatropus units are relatively small (about the same size as a mobile phone) but they have flashing lights and cables coming out of them, so you may want to tidy them away in a cupboard or drawer.

Step 3: Choose locations for your transducers

When you know where your Quatropus units are going to be located it is relatively straightforward to figure out where to place your transducers. Transducers are matchbox-sized and easily fixed in place using adhesive-backed hook & loop tape. Different transducers have different placement requirements so we list them all below:

Sensor-TRH (temp, humidity)

  • Place in an open location where it can measure representative temperature and humidity inside a property. For example, do not mount in a cupboard, or near a radiator, or near a window where it may be in direct sunlight.
  • Requires a cat5e connection (≤10m) to Quatropus.
  • Usually installed close to the Quatropus, using supplied 1m cat5e cable.
  • Full technical specifications...

Sensor-M (PIR motion detector)

  • Place so the dome on the sensor faces the area to be monitored - see specs for range, beam width, etc.
  • Usually mounted (using hook & loop tape) on a wall or bulkhead.
  • Requires a cat5e connection (≤10m) to Quatropus.
  • Full technical specifications...

Sensor-C2 (float & door/window proximity)

  • Typically used to monitor an included float sensor and an included door/window proximity sensor, but sometimes two float sensors or two proximity sensors.
  • Requires connections to Quatropus (standard cat5e ≤10m) and to float or proximity sensors (2-core, 24AWG, MTE-terminated cables, ≤100m - contact us for details).
  • Usually mounted close to Quatropus with longer cables running to float sensors (e.g. in bilge) and to proximity sensors on doors/windows.
  • See technical specifications for images of float and proximity sensors. Float sensor has a screw thread and bolts on its body, to mount onto a custom bracket. Proximity sensors are in two pieces (see images) and can be glued or screwed in place. 

Sensor-V2 (dual channel DC voltmeter)

  • Typically used to monitor the voltage of one or more lead-acid battery packs, or the activity of battery-powered circuits - for example a float-operated automatic bilge pump.
  • Requires a cat5e connection (≤2m) to Quatropus.
  • Also requires wired (2-core, ≤100m) connection to monitored battery or circuit.
  • Usually mounted close to Quatropus with longer wires running to monitored circuits.
  • SAFETY NOTE: be careful connecting to external circuits. Short-circuiting batteries or connecting to too high voltages could destroy the MaxMon system or cause a fire.
  • Full technical specifications...

Sensor-B (uninterrupted power supply & battery monitor)

  • Typically used to power the MaxMon system from mains power, or from battery power if mains power is absent. Also monitors the voltage of the connected battery.
  • This transducer has multiple wired connections.
  • Requires a 5V micro-USB input, typically derived from mains power via a phone charger.
  • Requires a wired (2-core) connection to a 12V or 24V battery.
  • Outputs 5VDC which typically powers a Quatropus via a ≤2m USB A-to-microB cable. You may use a high quality USB splitter cable to power two Quatropus units.
  • To monitor battery voltage connect a ≤2m cat5e cable from the Sensor-B to a free Quatropus port.
  • SAFETY NOTE: be careful connecting to external circuits. Short-circuiting batteries or connecting to too high voltages could destroy the MaxMon system or cause a fire.
  • Full technical specifications...

Sensor-S (mains power monitor)

  • Used to monitor total electrical mains power consumption at a remote property, using a current transformer clipped around one of the main power cables entering the property.
  • Requires a cat5e connection (≤2m) to Quatropus.
  • Requires a ≤50m standard 3.5mm audio extension cable (to reach meter box).
  • Usually mounted close to Quatropus with long extension cable from sensor to clip-on transformer in meter box.
  • SAFETY NOTE: the clip-on current transformer is electrically isolated from the mains cables. But do NOT cut cables or insulation or use with non-insulated cables. Contact a qualified electrician if you are in any doubt.
  • Full technical specifications...

Actuator-RF (remote control of mains power sockets)

  • Offers wireless control over off-the-shelf remote control (r/c) mains power sockets.
  • Requires a cat5e connection (≤10m) to Quatropus.
  • Range from actuator to r/c sockets ≤25m (no intervening metal).
  • Usually mounted close to Quatropus (using included 1m cat5e cable).
  • Full technical specifications...

Actuator-R2 (dual channel relay controller for 0-30VDC circuits)

  • Two-channel relay actuator capable of switching up to 5A at 0-30VDC, used to remotely control battery-powered devices (e.g. switching 12V lights on/off to simulate occupancy).
  • Requires a cat5e connection (≤10m) to Quatropus.
  • Typically ≤100m 30-12AWG 2-core wired connections to controlled circuits (max. length determined by wire resistance and application).
  • Usually mounted close to Quatropus (using included 1m cat5e cable), with longer wires to controlled circuit(s).
  • SAFETY NOTE: be careful connecting to external circuits. Creating short-circuits or too high voltages or currents could destroy the MaxMon system or cause a fire.
  • Full technical specifications...