the PCB layout is now generally complete. it just needs some silkscreen fanciness and a final look over to verify that the tracking is sound.

i may put some form of protection on the ethernet lamps, they dont have any right now

i put the design into aisler to get a RoM cost on the PCB and it is expensive at about £50 per PCB and MOQ of 3 which gives a total PCB cost of £100 per switchBox. this means it needs to be as close to perfect as possible as its very much a oneshot as theres probably about the same in components on the PCBA still, it should be fine...right?

after too many hours of searching for 5mm requirement clearenced ethernet connectors with no success i give up. this design will have to have the PCB butting againt the chassis panel. the USB connector will be reworked to provide the same amount of edge overhang as the ethernet connector

the contact connectors were revisited and actually the chosen part was fine, the model was incorrect but the chosen part was fine and its BoM information is now populated

the PCB is almost done just needing:-

• ethernet
• silkscreen tidying
• routing final look
• DRC
• any additional silkscreen

then it will be on to software! its been a long time coming

relayout in progress.

there are several component changes to make, they are:-

• longer ethernet connector - there is a 5mm pcb overhang requirement to allow connector access through the chassis wall
• contact connectors - when originally specified, there was insuffiucient bill of materials data and they are fairly tall

i will also need some series resistors as the traces are a bit long...

the next device that will be supported by skipper is the siglent SDM3055-SC. i have not yet decided whether to support the front panel or scan card first; there is a forced exclusivity between the two as when the scanner card is active, the chosen input is routed to the front panel

this will lead to a new DMM and scanningDMM? interface. the interface name for when a DMM with a scan card is used is currently undecided as this may fit better under a DAQ label but this is uncertain as i have not looked at DAQ that deeply

after many hours of work, the layout was complete. then the enclosure was drawn and does not fit. the layout(which was provisional) is now undergoing major rework

the mezzanine structure has been scrapped as it would impose too many cutouts, the two levels of PCB will be retained but their stacking will be directly above with wire to board connectors allowing the position offset

this has also triggered a rethink on the internal contact connectors as the existing vertical molex KK are fairly tall and the new layout allows more vertical freedom, the current connectors under review are molex microfit 3.0

front panel connectors are not under review as they still meet all requirements. i did think about instead fitting some D-sub instead but the lower cost connectors dont have the same current rating and this is a non-negotiable feature