I don't know what is going on with delivery services this week, but once again I had a bizarre elongation of a shipment occur here in Northern California. The plate was laser cut by Ponoko and ready for shipment by UPS Next Day air by midday Monday. Since I live less than 30 miles from Ponoko that should be an easy delivery for UPS.
However, UPS never showed up on Monday to pick up packages. Tuesday they accepted the Next Day Air package but then absolutely nothing happened all day Tuesday and up until very late Wednesday, totally blowing the delivery 'promise' of next day air. Finally by late evening it began moving and was delivered Thursday, turning an overnight shipment into a three day shipment.
Putting that aside, the plate was perfect as usual and I quickly mounted all the pins to allow me to enter five bit codes into five rows of relays, thus switching the segments on the EL panel to light up all five digits of the first (R1) register row. This adds to the Prog, Verb and Noun digits, the COMP ACTY light and the sign for R1 that were already being controlled by the first relay module.
WIRING THE NEW RELAY MODULE INTO THE EXISTING SETUP, PLUS A FEW ADDITIONS
I paralleled a number of lines between the two relay modules, such as the AC high and low wires and all the set and unset (latch/unlatch) connections. Therefore, when my Arduino activates a set for one of the five columns that encode a digit value, it will be present on that column of BOTH relay modules. Since both the set/unset and the selection lines must be active to actually operate a relay coil, as long as the select lines are unique to each relay module, this will work fine.
I did have to build five more driver circuits for the new select lines, hook those drivers to the Arduino and finish updating my firmware to allow me to put values into the digits. Fortunately the components arrived on time from Mouser today. These driver circuits were wired to the select lines on the new relay module.
Before I completed wiring the new module up to the segments for the R1 register on the EL panel, I tested the latch and unlatch for the digits. I set a few test values and checked for switched AC on the output pins of the relay module.
Once all appeared well, I did the wirewrap connection of the 35 wires from the R1 digits between Relay Module 2 and the EL Display Panel Module. Some visual inspection and sanity checking were conducted before firing up the project. Mainly I wanted to detect dead shorts of the high voltage AC and insure there was no leak of the AC over into the low voltage DC control lines.
DSKY EL PANEL WITH A TOTAL OF 11 DIGITS, A SIGN AND OTHER FEATURES ACTIVE
Here is a view of the panel working with everything I have wired up. If I wanted to take it to the next level, I would have to build a new PCB with 74 relays to take the place of Relay Modules 3 and 4, strictly to light the ten digits spread across R2 and R3 as well as the sign for those two rows.
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| Leftmost digit of R1 intentionally blank |
Since the relays would need to work safely with 275VAC on the contacts, I can't just grab the cheapest relays. In an ideal world, I would need 54 latching DPDT relays but that would make the cost and size extremely high, so I can settle for SPST relays with one per segment being controlled.
Frankly, the additional cost and work goes up dramatically yet the incremental value of seeing the other two register lines is not commensurately high. Therefore, I will stop at this point and declare the project a success.
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