It's right here!

This release is pretty significant. I am preparing to shift from the oft-repeated arduous process of hand-soldering modules... to creating printed circuit boards. I wanted to have the specs for the major connectors (DE-9, DA-15, DB-25, etc.) firm before moving forward with any production runs.

The key things that have changed:

• DA-15 is now an Enhanced Battery Connector.
  • LiPo batteries already have a balance connector. Why use an EBC instead?
    • Pretty much all balance connectors in the RC industry merely allow a battery charger to monitor two or more cells of a battery pack with an unknown chemical composition. The EBC spec supports battery packs with 6 cells (e.g. 6S) & includes one id pin. This pin has a resistor connected which can be used to identify both how many cells are in the pack, and what their chemical composition is. For instance, a 4S LiPo could have a simple 1.3Kohm resistor embedded within. Off-the-shelf battery chargers could include new functionality that analyzes the resistor value of the battery pack, compares it to the matrix & pre-loads the best settings for charging the pack.
  • LiPo batteries are already too heavy. Why add a heavy old-school DA-15 connector?
    • You don't have to! You can use a 16 contact socket IDC header instead. All 16 contacts are only really necessary on a fully-equipped 6S battery pack. A 3S pack would still use the 16 contact socket IDC header, but could terminate as few as four wires on said header.
  • Why not smaller?
    • There's nothing that would prevent use of a smaller connector. It seems, however, that good-ol' 2.54mm headers are best suited for external battery management, and 16 contacts seems to provide just enough functionality & flexibility.
  • Why no digital communication?
    • There is! I was able to squeeze in `one-wire-data` on contact 1. This digital bus allows one to embed inexpensive digital temperature sensors & similar into the pack.
  • Why support only LiPo?
    • They support more! Enhanced Battery Connectors support Pb (lead acid), NiMH, LiIo & LiFe batteries as well! As seen on the matrix.
• DC-37 is now 'The High-Def D-Sub'.
  • The connector now is spec'd to support HDBaseT (1080, 4K, etc), USB3, & standard BaseT connections. Example: "6x Raspi's and/or 6x Nvidia Jetsons sharing a backplane."
• Most connectors now support up to 40VDC.
  • Why so high?
    1. 24V battery systems (such as those in some RVs) may reach voltages as high as 36V while charging. I wanted Retro Modules to be compatible.
    2. A grid of 9x 18650's (a 3x3 9S battery pack) has a max safe voltage of 37.8VDC.
    3. While the average D-Sub contact can support up to 5A, D-Subs with IDC termination use wires that can only support about 1.2A each. An increase in the maximum supported voltage safely allows for more wattage on those same wires.
    4. Some module arrangements may have a common backplane, while some module arrangements may feature daisy-chaining. The higher voltage allowance helps reduce risk of connection-related power delivery issues.
  • Why not higher?
    1. 40VDC is the maximum voltage supported by many inexpensive DC-DC buck converters that use the LM2596 (or similar) regulator.
    2. Voltages over 50V can be considered dangerous (hat tip to: @Njkotzur via https://hackaday.io/project/45999-dewalt-flexvolt-60v-battery-adapter/discussion-100764)
• Many connectors now support (on a dedicated contact) voltages up to 15VDC.
  • Why up to 15VDC?
    1. Smaller modules may not have any room for a beefy DC-DC buck converter. The lower voltage limit allows for simple linear regulators (etc) if needed.
    2. Smaller modules may not need much power at all.
    3. Many 12VDC automotive accessories are able to tolerate up to 15VDC.
• Some connectors now support 12VDC with the ability to request more.
  • Why the complexity?
    • There are many 12VDC automotive accessories (and similar) that prefer just that: about 12VDC. The connectors (such as `din5-240`, `din6-240` & `din8`) will provide about 12VDC by default if a suitable power source is available. Some devices, however, make do with 12VDC -- but work better with higher voltages if they are available. These connectors (much like functionality described in USB-C PD documentation) are able to provide more power if a source can provide it & the client device requests it.

This spec is becoming easier & easier to work with. I'm now able to manually make one or two modules in an evening with great ease. I'll be posting a few new (related) projects soon!