Thursday, May 11, 2006
The big picture
The solution for driving the upper panel (from small gauges to large gauges) is slowly getting shape. I will need 5 or 6 PICs to drive the servos and (in case of modified servos) read position feedback, optical interrupter, rotary encoder, things like that.
I will build:
"power board"
6 DB9 connectors to connect to PC's 6 serial ports
power connector to standalone ATX power supply (hacked to power up without PC)
dimmer circuit outputting 5V-10V regulated by potentiometer
6 DB9 connectors to connect to "control boards", this connection will provide TX,RX,GND,+5V,+12V,dimmer output to control boards
"control board"
1 DB9 to connect to power board and receive TX,RX,GND,+5V,+12V,dimmer output
78L05 to create +5V from +12V for logic circuit
MAX232N to interface to RX,TX
PIC16F628A or PIC16F88 as needed
connectors as needed (illumination LEDs from dimmer voltage, servo connector etc.)
servos will be driven from +5V from ATX power supply (to separate from logic circuit)
PC - power board and power board - controller boards are connected with null-modem or serial extender cable (I have to make sure not to mess up which line goes where).
It means installing 4 additional serial ports to the PC. Not really nice, but this way I can develop and test different control boards individually and later simply plug them all into PC. Also it (hopefully) eliminates the need for some kind of addressing scheme (PC control software will "know" which control board is connected to which COM port).
"Miles to go before I sleep" :-)
I will build:
"power board"
6 DB9 connectors to connect to PC's 6 serial ports
power connector to standalone ATX power supply (hacked to power up without PC)
dimmer circuit outputting 5V-10V regulated by potentiometer
6 DB9 connectors to connect to "control boards", this connection will provide TX,RX,GND,+5V,+12V,dimmer output to control boards
"control board"
1 DB9 to connect to power board and receive TX,RX,GND,+5V,+12V,dimmer output
78L05 to create +5V from +12V for logic circuit
MAX232N to interface to RX,TX
PIC16F628A or PIC16F88 as needed
connectors as needed (illumination LEDs from dimmer voltage, servo connector etc.)
servos will be driven from +5V from ATX power supply (to separate from logic circuit)
PC - power board and power board - controller boards are connected with null-modem or serial extender cable (I have to make sure not to mess up which line goes where).
It means installing 4 additional serial ports to the PC. Not really nice, but this way I can develop and test different control boards individually and later simply plug them all into PC. Also it (hopefully) eliminates the need for some kind of addressing scheme (PC control software will "know" which control board is connected to which COM port).
"Miles to go before I sleep" :-)
# posted by ltornyi @ 10:04 AM 
