benkrasnow / dsky_el_replica Goto Github PK

In doing some research on selecting an "optimal" value for current limiting resistors in EL Display Driver design, I came across this reference: https://patents.google.com/patent/US5095248

I suspect this might be applicable here -- any thoughts?

Subj, please fix ASAP

Hi Ben,

I was looking at the last committed Segment PCB layout in GitHub and comparing that with your YouTube walk-through video.

I see what looks like the Common protection diodes you mentioned at the end of your video already on the Segment PCB (1)-- I see sixteen parallel Common lines rather than the eight you mentioned in the video, though (2).

I'm guessing you made a late change in the number of Common driver lines subsequent to producing the walk through video -- correct?

I'm guessing we'd still put one current limiting resistor on each Common driver line (you mentioned a value of 47K Ohms elsewhere) -- if all that is correct, I might just put together an updated board layout and get a fresh batch of Segment boards made.

Your thoughts?

I was wondering what hardware you run the https://github.com/benkrasnow/DSKY_EL_replica/blob/master/software%20-%20Processing.org/DSKY_serial_control_tester/DSKY_serial_control_tester.pde Arduino program. You ran that on a Windows PC connecting to the Driver board with a USB A-to-microB cable, correct?

Ben, do you ever use the USB interface on the Driver board? I'm noticing that VBUS (pin1) on X1 doesn't seem to be tied to anything. That's a bit different than the Trinket M0 where the core design seems to be derived from.

I'm guessing that means that you'd first power up the board using the power plug before connecting the USB. Just curious.

I am working on adding current limiting resistors as we discussed and I'm just looking at the Driver schematic. There don't seem to be connecting wires between the HV507 output lines and the connectors. Was that an oversight in the SCH file that was committed or did you route each of those manually on the PCB design?

Decided to open this as a new issue/question (rather than adding onto the closed BOM issue)

Hi Ben,

I was watching your video and noticed that you mentioned that you'd added some current limiting resistors to the HV507 outputs that drive common. But, I don't see these resistors on the driver or segment schematics... am I missing something or looking in the wrong place?

I've been working non-stop on this project for a while, and want a
rest to work on other things. I don't have time to make 10 glass panels, but
if there is enough interest, it may make sense to contract some work out, and
maybe do some work in my shop. I'll let you know.

I'm interested as well! I'd buy 2 or 3.

Thanks & best regards,

Craig

I worked this change up last night. Sixteen 0402 75K (or 100K) resistors.
CircuitHub will make a batch of 10 unpopulated boards for about $220 and 20 for only $20 more. Want any?

I can send you a pull request with the modifications.

Awesome project Ben! Keep up the great work.

Hi Ben,

Since mid last year I've been contemplating using the Lumilor paint to create a DSKY EL digital indicator, so I was pleased to see your project was a success. I hesitated because Lumilor says you need to use an HVLP gun with their paint.

I don't know enough about airbrushing to have an opinion on using an HVLP gun, but I was startled to discover that most HVLP guns require 5+ CFM, and that even my middling air compressor puts out less than 2CFM... and that compressors that can put out 5+ CFM can be expensive. Sadly, Amazon doesn't specify the CFM required by the PowRyte guns.

Where am I'm going with this?

A question: did you use a high (5+) CFM compressor with that small PowRyte HVLP gun, or did you use a standard work shop (or air brush) compressor (<2 CFM)?

If you used a <2 CFM compressor with the small PowRyte gun then my existing compressor should suffice as well. If needed to use a high CFM compressor with the PowRyte then I'll likely trying using a Paasche HG-08, which (best case) only requires 1.5 CFM.

Thanks,

Craig

Do you have a BOM for the PCBs?