jayachar88
Member level 3
hi,
this is my first post here, and a rather long one at that. have read the stickies, and done a search before posting. if in spite i miss something, plz excuse and point it out
i am a programmer by training/education, and have limited (but exciting) experience using Arduino (Duemillanove USB to be precise), but very limited understanding of anything more than basic electronics -- especially so for analog electronics. willing to learn though, and thus these questions.
objective: design mcu based ckt that acts as slave, accepts short-range RF signals from a main controller (master), and turns on/off mains electrical equipment (230VAC-50Hz), including equipment like lights, fan, TV, music-system, refrigerator, and even water pump/motor (rated at 1.5kW). also it should be able to send back acknowledgement, and few other pieces of data s.a. overall health, status etc., to the master. this slave device should ideally be mains powered, and have optional battery backup.
From slave standpoint, I think MCU needs atleast 3 GPIO pins -- 1 pin to control (on/off) device (+ into the Relay), 1 pin for serial rx and 1 for serial tx. If it doesn't have a USART, I could fallback on bitbanging. the rx/tx pins connect to some RF module. For the RF part, my search tells me the 433/315MHz ASK may be the cheapest option for short-range comm. (basic command/response).
The master controller, for now might be a PC with a 433MHz/315Mhz usb dongle, but eventually a MCU based independent design.
I am aware that the above is a common objective of home-automation devices, but I'd like something DIY.
questions:
1. Does the description of slave circuit above sound reasonable or is it incoherent ?
2. for the slave-device, what mcu could lead to cheapest overall BOM considering that the mcu has a reasonable C/tiny-C/small-C programming environment. The question of cheapest needs qualification. Idea is to see if possible, make a commercial venture out of this , so consider something produced in say 5-10k lots.
3. any existing reference design that could be leveraged for this sort of thing ? designing a complete circuit from scratch isn't exactly something I have high hopes of achieving.
all pointers / suggestions welcome.
thanks,
jay
this is my first post here, and a rather long one at that. have read the stickies, and done a search before posting. if in spite i miss something, plz excuse and point it out
i am a programmer by training/education, and have limited (but exciting) experience using Arduino (Duemillanove USB to be precise), but very limited understanding of anything more than basic electronics -- especially so for analog electronics. willing to learn though, and thus these questions.
objective: design mcu based ckt that acts as slave, accepts short-range RF signals from a main controller (master), and turns on/off mains electrical equipment (230VAC-50Hz), including equipment like lights, fan, TV, music-system, refrigerator, and even water pump/motor (rated at 1.5kW). also it should be able to send back acknowledgement, and few other pieces of data s.a. overall health, status etc., to the master. this slave device should ideally be mains powered, and have optional battery backup.
From slave standpoint, I think MCU needs atleast 3 GPIO pins -- 1 pin to control (on/off) device (+ into the Relay), 1 pin for serial rx and 1 for serial tx. If it doesn't have a USART, I could fallback on bitbanging. the rx/tx pins connect to some RF module. For the RF part, my search tells me the 433/315MHz ASK may be the cheapest option for short-range comm. (basic command/response).
The master controller, for now might be a PC with a 433MHz/315Mhz usb dongle, but eventually a MCU based independent design.
I am aware that the above is a common objective of home-automation devices, but I'd like something DIY.
questions:
1. Does the description of slave circuit above sound reasonable or is it incoherent ?
2. for the slave-device, what mcu could lead to cheapest overall BOM considering that the mcu has a reasonable C/tiny-C/small-C programming environment. The question of cheapest needs qualification. Idea is to see if possible, make a commercial venture out of this , so consider something produced in say 5-10k lots.
3. any existing reference design that could be leveraged for this sort of thing ? designing a complete circuit from scratch isn't exactly something I have high hopes of achieving.
all pointers / suggestions welcome.
thanks,
jay