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HowTo: Simple PIC-Based 8-Port Dimmer
( Phil Short)
Step 2 : Build the Hardware
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| | Build the hardware shown in the attached schematic. The schematic shows a single PIC, but multiple PIC chips can be daisy chained together on one PCB by wiring pin 6 of each PIC to pin 5 of the next one (all of the pin 2's can be connected together, as can the pin 4's).
The top connector J2 is to be connected to 110VAC for detecting the AC-Line zero-crossing. This part of the circuit is basically the same as in the 'Dimming the Olsen-595' How-To.
Pins 1 and 2 of the next connector (J3) are connected to TxD and ground on the RS-232 serial output port of the controlling computer (or to pins 1 and 2, respectively, of the J4 output of the previous controller in the chain).
Power is provided to the controller through J5. This should be connected to a source of regulated 5VDC using a circuit of your choice. Plan on providing about 5mA of current for each PIC (the duty cycle on the SSR opto-isolators is 1:256, so the average current for each SSR input is below 1/16 mA) plus about 45 mA for the oscillator.
J4 on the right side of the schematic is connected to J3 of the next controller in the chain.
J1 is the connector to the SSRs (sink-type connection). These SSRs can be similar to those described in the Howto: '4-channel SSR to go with the controller in the "How To"' (by Sean Bowf), although an adapter cable would be required in this case. J1 could also be directly connected to a Triac8 board from simpleio.com configured for sink-type connection and using non-zero crossing opto-isolators (although I haven't tested this, so there are no guarantees).
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