Green Smart House Solution - Max-i Fieldbus

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The Green Smart House Solution
A different Solution
Most other smart house systems are based on wireless communication and devices driven by small batteries or mains voltage, but there are a lot of disadvantages:

  • Wireless communication may be disturbed by other communication in the same band, may be hacked and jammed, may disclose information about your behavior and can be difficult to setup.
  • Battery powered devices are often chosen because they are easy and cheap to install, but the batteries require resources to make and recycly, do not have power enough for example for intelligent and fail safe alarm sensors and they must be replaced fairly frequently if a device is to be expected to work. This can be a problem for example for radiator thermostats, locking systems and access control. Besides, battery leakage can cause bad connections and corrosion.
  • Mains driven devices including LED bulbs and chargers include a converter, which
      • increases the price and size of the device considerably and may even be a clumsy "brick" on the charging cable,
      • require big resources to make and are difficult to recycle due the the use of toxic epoxy boards and big components with the result that the device often just end up as waste in the incinerator or even on the landfill,
      • limits the service life of the device considerably - typical to less than half, which makes the waste problem even bigger.
      • generates electrical noise and may turn off for a short time in case of transients or voltage drops,
      • often results in a chaos of socket outlets and cable spaghetti on the floor with very low "Woman Acceptance Factor",
      • may even cause a risk of fire and/or shock due to the high voltage levels and often very doubtful quality and cooling.
  • The necessary conversion to and from mains voltage makes it very expensive to utilize a battery and solar panels to save energy, as an inverter system is needed to generate AC. This also significantly reduces the service life and the efficiency at low power levels.


Max-i offers the ideal solution to all those problems. The high power capability and use of standard installation cables makes it extremely suited as a supplementary 20-Vdc power supply with control possibilities in the houses of the future where it can replace all the mains converters and chargers and be used to drive and control for example LED lighting, window openers and sun shading, computers, tablets and peripherals like screens and modems, low power entertainment systems including TV, low energy refrigerators and freezers, door bells, coupled smoke alarms, burglary alarms and locking systems. In a typical house, such devices use approximately 65 % of the electricity exclusive electric heating, so in case of solar panels, a huge energy saving is possible at a fraction of the cost of a traditional AC system, which is also designed for driving all the high-power devices like stoves, ovens and other kitchen appliances, washers and dryers, vakuum cleaners etc. Calculations done by the Danish engineering company Rambøll shows that such a network can save the Danish households in the order of 1 billion Danish kroner per year corresponding to approximately 134,000,000 Euro or $144,000,000.

The use of 20 V (maximum 5 A per outlet) fits with the maximum level of both USB Power Delivery (USB-C) and Quick Charge and is simultaneously the highest voltage, which do not cause arc risk at high current levels. Since the charging voltage of a 20-V battery fits very well with the maximum-power-voltage of 48-cell or 54-cell solar panels, such panels may be connected directly by means of a simple Max-i controlled switch as shown on the drawing on top of this page, which also shows the "multi-loop plus two tails" structure, and the charging current may then be controlled in steps of typical 20 - 180 W depending on the sun light. In sunny areas, it may be possible to drive the devices totally off-grid even in the winter, and the excess power in the summer may then for example be used to drive a ventilation heat pump so that the house gets ventilated and additional heating is not needed most of the year, which can save a lot of energy. The outlet of cold, dry air can even be used for a (supplementary) compressor-less refrigerator to squeeze the last efficiency out of the system and make the household even less vulnerable in crisis situations where refrigeration capacity for food is vital. In less sunny areas, a grid-powered charger may be necessary to supplement the solar panels, but it can be quite small and thus inexpensive as it should only be able to deliver the average power. Since the voltage is always lower than approximately 35 V (open circuit voltage of panels), there is never any shock hazard even in case of fire extinguishing by means og water, which may be very dangerous on traditional serial connected systems.

For smart house applications where there is no problems with mutual coupling to other cables, Max-i uses a 5-conductor flat cable with two conductors (1 and 5) for positive voltage (L+), two (3 and 4) for negative voltage (L-) and one (2) for communication (COM), and it uses piercing technic to get contact without cutting the cable. If more power is needed than possible with a pure 20-V system, conductor 4 and 5 may instead be used for mains voltage (mains-plus-dimming) as shown below:

Security and Privacy
Security is of the utmost importance to many people, but it is an area where present technology based on wireless communication and small batteries is almost useless:

  • If an alarm system should not give you false security, it must be fail-safe, that is, an alarm is also generated in the absence of a sensor signal - not just as an active signal. If a wire is cut or the system is jammed, an alarm must be generated in less than 1 second, but due to the battery life, it is usually not possible to supervise a device more frequently than approximately once every 10 minutes.
  • Battery driven systems only have enough power for simple, low-power sensors such as passive infrared detectors (PID), but these kind of sensors generate many false alarms and may be easy to fool.
  • Wireless communication is very easy to jam and may generate false alarms due to other wireless communication in the same frequency band. False alarms and jamming are not only very irritating, but also makes you nervous and it can even be used to force you to switch the system off. A thief just needs to jam the system from time to time to trigger it.
  • It can be very difficult to ensure that wireless communication do not disclose information about your home. This is especially a problem with alarm systems with cameras where it is almost imposible to guarantee that your behaviour is never transmitted to third parties or to second parties such as alarm centers when you don't want it. If you even add a cloud based speech recognition system, your privacy is gone forever. Everything you say or do may end up on the wrong places on the internet, and even though it only ought to be the commands to a speech recognition system, which are transmitted, there are people listening to optimize the systems!
  • Wireless connection may be used to hack into the system even from a long distance. The safety is not better than the weakest link and the majority of devices are not updated after some time or not at all. Just one unsafe device is enough to open a backdoor into your system on the wrong side of the firewall where there is free access to your other devices and computers.

With Max-i, it is different.

  • It has power enough for locking systems and even the most advanced and fail safe sensors.
  • It is fast enough to destroy the night vision of a thief by means of powerful light flashes.
  • It cannot be jammed unless you get physical access to the cable or an outlet with enabled communication, which should only be possible from alarm monitored areas.
  • The Max-i controller (chip) is entirely hardware based and therefore cannot be reprogrammed to anything else than its dedicated purpose so there are no "mousejack" problems etc.
  • It is very easy to log all communication to ensure that nothing or nobody transmit unwanted information behind your back. The Max-i controller even has a fairly advanced and hacker proof acceptance filter, which can block telegrams, which would otherwise overload the log-system.
  • Unlike for example WiFi, there is virtually no limitations on how many devices you can connect without any noticeable degrade of performance.
  • In daily use, you don't need an internet connection, which keeps even the best hacker out. Even when you need it, the connection only goes through one device, which is much easier to keep safety updated.

Simplicity in use.
Max-i may be operated any way you want. Even without a central controller, you may for example control lamps, window openers etc. by means of traditional wall mounted buttons, which is usually the most convenient. In the long run, almost no one bothers to find the right app on a mobile phone every time they just want to turn a lamp on or off. The only difference you will experience with Max-i compared to a traditional system is perhaps a more beautiful touch control with light indication and that you simultaneously get a light dimmer in all lamps with a lot of features like night light and programmable start level, automatic daylight control, all-off (and all-on), synchronized multi-way landing switching and possibility for emergency light with programmable color (need to be reddish in case of smoke). If you connect the bus to a WiFi or Bluetooth interface, you may do the same from mobile phones and tablet and this also makes it possible to set different scenes and control the color hue in case of multi-color lamps. Max-i may of course also be connected to controllers and computers, which can enable more advanced functions like energy management and making the home looks inhabited when you are not at home. It is even possible for an advanced TV to control the light in real time from the image lighting with the same speed and performance as professional stage light.

"Everything should be made as simple as possible, but not simpler."
Albert Einstein

"Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away."
    Antoine de Saint-Exupéry.

.This page is created with WebSite X5 and updated April 11th 2020
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