DARKROOM TIMER Display LEDs & PB's
This
section is the visible end result of all settings, the actual
'time left' function in progress using 5 x FND500/560 LEDs
plus a 'double adaptor' function to permit the 'remote' use
via a common floppy drive cable (34way IDC) and to allow
a larger (2.3") display up on the wall, several feet (2+ metres)
so as others in the DARKROOM can see 'cause & effect'
The 5
x 7 Seg (FND500/560) LED readouts are used as follows.
MINUTES x 10, minutes x 1, SECONDS x 10, seconds x 1
plus tenths or deci - seconds for better accuracy.
(at RCS, we use 8.3
seconds @ 15w for Ortho B/W film exposure)
(and we use 44 seconds @ 400w M.V. for RISTON 'AE' exposure)
(with appropriate O.H.& S. Donut & Coffee breaks)
The
3 duplicate Push Buttons are my only 'luxury' , using up
spare space on the Display Board so as 'remote' Push Buttons
can be used, in case the others are buried in a small panel/case.
If using the JAYCAR HB6094 case, then the Push Button board
can be left attatched to the FND 500/560 LED Readouts board
or it can itself, be guillotined off and mounted elsewhere.
The double
adaptor 34way, IDC (floppy disc drive adaptor)
should be used if you want BOTH displays to work, the local 5v
Display LEDs and the remote 12vDC LARGE LED READOUTS.
The practical
use of 3mm RED LEDs
for the HhSs
colon was
a simpler way rather than software and waste a PIC pin
as well as the deci-point single LED
indicator, you will notice
a pair of pads, below the 34way IDC connector, this is in case
you wish to cut the track between these pads and insert an
el-cheapo ' LED' on the under side surface 'hidden'
so as the local readout here on the small panel box looks 'ALIVE'
shall we say 'political cosmetic presentation', your call or use.
Section D (Display) & Section
C (more Push Buttons)
5 x FND500/560 7 SEGMENT LED Readouts & 3 more Push
Buttons
7 Segment FND500/560
LED Display & Extra
(duplicate) Push Buttons
Don't
forget to send in an S.A.E. for an
A4 checkplot of the circuit board etc.
