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 battery- and/or mains-driven devices, but there are a lot of disadvantages:

  • Wireless communication may be disturbed by other communication in the same band, may be hacked and open a backdoor into your system on the wrong side of the firewall where there is almost free access to your other devices and computers, 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, which may cause false alarms and false security, 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 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 TV and other entertainment systems, 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 systems, which are designed for the entire 100 %. 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. With a sufficient number of solar panels and a big battery, 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, additional heating is not needed most of the year and the outlet of cold, dry air can be used for a (supplementary) compressor-less refrigerator. This can save a lot of energy and make the household much less vulnerable in crisis situations where cooling capacity for food is vital. 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:

Daily use
Max-i may be operated any way you want. Since all devices can communicate with each other without the use of a central controller, you may for example control lamps, window openers etc. with traditional wall mounted buttons, which is usually the most convenient. Almost nobody wants to find the right app every time they just want to turn a lamp on or off. The only difference you will experience with Max-i is perhaps a more beautiful touch control and that you simultaneously get a light dimmer in all lamps with night light, programmable start level, automatic daylight control, 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. In case of burglary, it can alarm the neighbors and with a few high-power stroboscopic lamps, it can even destroy the night vision of the thief. In the future, it may even be 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.

Unique Privacy
Connect a WiFi based camera and a cloud based speech recognition system to your smart house and your privacy is gone. Everything you say or do may end up on the wrong places on the internet or just in an alarm center and since such devices are seldom safety updated, it just gets worse over time and the safety is not better than the weakest link. 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 and nothing prevents that everything is transmitted if the possibility exists. If safety is only handled by software and/or a device can do other things than it is supposed to do, it is just a matter of' time before you don't have any safety anymore. Just search the internet for "mousejack" if you are in doubt!

With Max-i it is different. The Max-i controller (chip) is entirely hardware based and therefore cannot be reprogrammed to anything else than its dedicated purpose and in daily use, you don't need an internet connection, which keeps even the best hacker out. Even when you need remote access, the connection only goes through one device, which is much easier to keep safety updated, and unlike wireless systems, it is very easy to log all communication to ensure that nothing transmit unwanted information behind your back and/or a hacker is controlling the system. The Max-i controller even has a fairly advanced and hacker proof acceptance filter, which can block telegrams, which would otherwise overload your log-system.

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

.This page is created with WebSite X5 and updated March 23rd 2020
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