DB2.1 1.0

DB2.1 v1.0 - 2 Button Doorbell
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Developer	Alexander Christian
Status	In Development
Microcontroller/Board	M0dularis+
KNX connectivity	MicroBCU

Description

PCB replacement for 2n Entrycom IP Uni doorbell. It will have 2 buttons with RGB background LED light and a speaker for PCM WAVE playback.

Hardware

M0dularis+ is used as base-controller.

				Description	Pin		Description
				GND / KNX GND	1	2	GND from 24V Input
			SJ: 3.3V	VCC	3	4	24V from 24V Input
			PA22/SDA	SDA / IO0	5	6	IO3	SJ: PA02/A0	PCM Audio Output via DAC on A0
			PA23/SCL	SCL / IO1	7	8	ExtINT Application / IO2	SJ: PA18/D10*#	ReedRelay Speaker Enable
		PWM R on LED1	PA09/D3*#	Option0	9	10	Option7	PA17/D13*#	PWM R on LED2
		PWM G on LED1	PA08/D4*	Option1	11	12	Option6	PA16/D11*#	PWM G on LED2
		PWM B on LED1	PA15/D5*#	Option2	13	14	Option5	PA20/D6*#	PWM B on LED2
		Button 1	PA14/D2#	Option3	15	16	Option4	PA21/D7#	Button 2

Solder-Jumper (SJ) configuration:

• IO3: SJ to A0
• IO2: SJ to D10
• Application connector: SJ to 3.3V
• Frontend connector: SJ to 3.3V (but is unused)
• I2C (on IO0/IO1): PullUp

* = PWM capable
# = INT capable

24V from yellow/white bus connector -> LM2596 step-down buck converter module -> 5V supply voltage for amplifier + LEDs

Software

The software enabled the user to fully have control over the buttons. One idea ist to have multiple states for the buttons. For instance

• Default (white background light): Rings the bell
• Postman (yellow background light): Ringing the bell will playback a wave file, telling where he can put the package that you are waiting for. Additional things can be triggered by calling a KNX GroupAddress, f.i. open the garage door half a meter so safely store the package.
• ...

Open Questions

• how to get files onto the SPI flash?!

-> see filetransfer via Bus PoC

Links

• https://github.com/arduino-libraries/AudioZero
• https://github.com/PaulStoffregen/SerialFlash