Reply To: SDI-12 Change Address for Meter Hydros 21 CTD Sensor

The Mayfly is not designed to have 2 microSD cards inserted at the same time. No one should ever insert two cards. The reason for the second vertical socket is for people who have the logger mounted inside an enclosure that makes it difficult to remove the card in the regular horizontal socket. Various electrical irregularities will occur if you use two cards at the same time, and the processor will only write to one card anyway, so there’s no benefit to having two cards in together.

So are you saying that the board performs properly as long as you’re using only one card? Because I have seen a few of the optional vertical memory card adapter boards have the bent pin that results in the short circuit when a single card is inserted. The issue is fixed by simply replacing the vertical memory card board. I’ve never seen a Mayfly have the issue with the onboard horizontal memory card socket because that’s one of the things I test for before shipping each Mayfly.