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@neilh20
5 days agoHey @ Shannon, thanks for posting the Eagle files, and I was able to convert them to Ki-CAD to be able to follow the circuits/pcb . Really appreciate there is a lot of effort gone into Mayfly rev1a3, and some risk with new circuits. Really challenging with such small components.
I’ve received three rev1A3’s so looking forward to trying them out, but I would like to know where the current states goes from “cutting edge” to “bleeding edge”.
You’ve hinted that the +12V isn’t meeting design spec, but it is possible to simply measure and specify this. I created a tracking item with my cct analysis ..https://github.com/EnviroDIY/EnviroDIY_Mayfly_Logger/issues/33
When I’ve asked technical questions in the past, I haven’t got an acknowledgement that there may be something tricky, so I’m humbly checking in and trying to be helpful.
From a paper analysis I’m concerned with is the powering of the Xbee socket. For the Mayfly 0.5 it required a separate LTE board to provide sufficient power to have it run, and very obvious that it needed specific LTE powering.
I’m wondering how much testing has been performed with an LTE device (eg Digi LTE Xbee3 CAT-M1) .. and that maybe none at this stage due to software support/complexities.
I’ve put up a Norton Current analysis of the LTE powering on https://github.com/EnviroDIY/EnviroDIY_Mayfly_Logger/issues/31
For me engineering is about being reliable – a vehicle that some times doesn’t start when the temperature drops below 10C, doesn’t give me much confidence. If I’m in a cold climate I need to how cold it can get and the vehicle will be guaranteed to start – eg -10C.
Since you are talking about a new revision, one of these reliability areas is on measuring LiIon battery power from a discharged battery that is charging. It could do with some discussion how to solve it, and maybe there is a simple solution. Not sure where the discussion could be, so created issue https://github.com/EnviroDIY/EnviroDIY_Mayfly_Logger/issues/32
@Shannon Hicks – I wonder could you provide a technical list of target/designed functional specs and what is tested and what hasn’t. Its pretty standard to be transparent for a new product, and to list the issues (sometimes a bug?) against the revision.
What’s really hard is not knowing if something is supposed to be working, and testing it only to then find its “known broken”.
Looking at your comment, as an EE, there is “current-limiting circuitry in another part of the board” doesn’t make a lot of sense to me. Its either generating +12V with an available power rating, or its not generating any 12V. My method of testing – if its generating any 12V, is to put a large power resistor on the 12V with a series amp meter, and scope, and wind down the resistance looking for when the 12V droops and or oscillations start up. The chip also says its short circuit protected. So either Mayfly 1.0 A3 supports this to a given power OR you need to indicate that its broken for A3.
thanks – neilh01@wllw.net. Great to see them on Amazon. Congrats a big milestone I’m sure.
I was discussing it with a Sonoma State Uni project, and they searched amazon found them and ordered the new boards. They have a timeline for a prototype and then a project for the Sonoma Center for Environmental Enquiry Fairfield Osborne Preserve.
Just wondering, will you be putting out the BOM with parts number?, in a location like https://github.com/EnviroDIY/EnviroDIY_Mayfly_Logger/tree/master/hardware. While I appreciate the overview on the new Mayfly, there is only so much that one person can respond to when it comes to detail.
For instance would be nice to know what the voltage rating are on C33, C2, D1 and D2.? bq24074 OVP is rated up to 28V.
