[Ovmsdev] V3 size and arrangement

[Edward Cheeseman]

On 19/05/2017, at 10:48 PM, Mark Webb-Johnson wrote:

>> Personally, the v2 size is great 
> 
> Even if it was thicker? OVMS v2 is approximately 73mm x 73mm x 23mm.
> Making room for two stackable boards would probably increase it to 73mm x 73mm x 43mm.

The toll road things are thinner than 23mm, but there is height room to grow into.

I've lost track of why two expansion boards are needed but I think it was for GPIO expandability. Having the cell modem changeable seems sensible given the international fragmented cell frequencies.
Given that, I can't see how to fit them in without going to the height you have said.

Simple answer: I like your stacked version better. The wider version wouldn't be a deal breaker though. Let's see what others think.

> SIM card slot accessible from outside is not so easy. Most of the trays around here are all top-down attached. A slide in tray may not be so easy to find. Why do we need to change SIM card so much?
Only for development - I think I have hit an issue with a local cell provider and the SIM808 module not being able to reply to SMS. If it had been easily accessible I would have swapped a few SIM cards in to try. But no, it's not a real product requirement so disregard.

>> More generally to make a more reliable product: expansion boards need to be mechanically latched. 
> 
> Really? Even with two rows of 14pin SIP socket? That is pretty robust. I can ask what the manufacturer recommends.
Automotive is a high vibration environment, and friction alone can work loose. Maybe a recommendation to use a bit of hot glue, or cram some foam between the expansion boards and case would be more than sufficient.
So again, probably don't bother as there are simple ways of fixing it if it ever becomes an issue.

Edward