Multi Function Input Device

 

The multi function device can be used for the following functions:

  • transmitting the status of a open/close contact
  • transmitting the status of a PIR (movement) sensor
  • detecting a AC or DC signal
  • touch input switch

It can be powered by battery or a DC supply voltage between 5 and 24 Volt. The function is dependent on the hardware components on the PCB. Not all functions can be used at the same time, as hardware components overlap each other.
As the device can be put to sleep most of the time, the current drawn can be very low. If only the touch control function is used, the batteries will last for several years as the unit draws about 1 uA during sleep, and is only transmitting when it is touched. If it is used as a PIR device, the battery life is determined by the PIR unit, which draws about 50 uA.

Here is the schematic of the board:

The PIR device can be mounted on the 3 pin header. It is a device that is known as DYP-ME003 and can be bought from several sources. It's cheap and easy to use. The device contains a 3.3 Volt regulator and is supposed to be powered by a  supply voltage between 5 and 20V DC.  If the board is powered by battery (2 x 1.5 V AAA), the voltage regulator on the PIR device should not be used. The input and the output of the voltage regulator on the PIR board can be easily short circuited. See picture.
This change of the PIR unit actually leads to another issue:
When the Zigbee unit is transmitting it draws about 40 mA from the battery supply. This causes a sudden voltage drop, which directly influences and triggers the PIR unit. To overcome this, the voltage has to be decoupled from the battery by a RC filter (R6/C10).

If the device should be used as touch control sensor, the TTP223-BA6 has to be mounted on the PCB. The device has two settings (by means of 2 x 2 pin headers). One to control the active state and one to set Toggle mode.

For touch sensing a wire can be used, glued at the inside of the top cover of the housing (as a flat kind of coil).

The device is self calibrating at power up. If the device is powered by battery (which is probably the case), power is applied when the batteries are inserted. At that time the unit is not yet closed, and the automatic calibration function will calibrate the device in the unboxed state. If the unit is closed later on, the touch control will not function correctly; it has to be calibrated in the new situation. As the TTP223-BA6 is only consuming micro amps, it can be powered from a Z100A output and as such it can be repowered (re-calibrated) by software.

The device can be programmed as one of the following Zigbee devices:

  • a On/Off switch (deviceId 0x0000)
  • a Simple Sensor (deviceId 0x000C)
  • a On/Off Light Switch (deviceId 0x0103)

There is a major difference between a On/Off (Light) Switch and a Simple Sensor. The status of a switch can not be requested or reported; the switch can only send an OnOff or Toggle signal to a device it is bound with. A Simple Sensor has an attribute "Present Value" which can be requested and/or reported by/to a device it is bound with.