Just sharing this bug here, as it’s kinda funny… Half way through my training session, the Tickr X decided to invert the readings, looks like 210 - HR… check it out… My heart rate goes up as I recover
Would be great to fix, but in the meantime what’s the fastest way to reset it? I tried disconnecting the press-studs for 10 seconds and also disconnecting in the running SYSTM desktop app, but no change. Right at the end it seemed to fix itself, but by then the session HR recordings were useless.
To reset, open the battery compartment, remove the battery and reverse polarity put the cover back on for 3 full seconds then, put it back the way it is supposed to be.
As an electrical engineer, putting the battery in backwards gives me the heebie jeebies. But if that’s the design… will give it a go next time, thanks!
I am a professionally qualified electronic engineer, with nearly 25 years in my field.
Without asking to see the circuit schematics, I would like an explanation of how reversing the polarity
Batteries provide power if there is a closed circuit. If there is no circuit, nothing more will happen than just taking the battery out - without some other special circuit going on.
How are components being “overcharged”? That sounds like a tremendous design fault straight away.
Without some sort of reverse polarity protection on sensitive circuits (ADCs, at least), damage could occur. Capacitors should discharge (probably slowly) with just the battery removed.
Similar to @gwydion, I wince whenever I read this instruction and it goes against almost everything I’ve learned.
I’m no electrical engineer, but I once barely passed a class in it on my way to being a mechanical engineer! Anyway, with the coin style battery, wouldn’t flipping it upside down more or less ground it out since both contacts would be negative to negative instead of negative to positive? That’s the only thing my non electrical brain can think of….
The load circuit has no concept of positive and negative. The “ground” is provided only by the battery. Demonstrably this cannot be ground but can only be one side of the battery.
Batteries only provide a difference in potential - positive and negative are naming conventions only. Current flow (by convention) will still occur from higher potential to lower potential, if a closed circuit exists.
Reversing the polarity to the load circuit just means that the higher potential is now connected to parts of the circuit that are not designed* to receive higher potential (electrolytic capacitors, for example, do not behave very well when reverse biased. Small transistors may fail completely when reverse biased meaning the cannot behave correctly when correctly biased).
*unless the circuit is designed for this but I can’t imagine what this really looks like if the only reason to reverse the polarity is to initiate some sort of device “reset”.
But I think I have the answer… Putting the battery in backwards doesn’t reverse the current direction, due to the position of the battery contacts. Putting it in backwards will cause both positive and ground terminals to make contact with the larger positive surface of the coin battery, while the negative surface is isolated. That connection would short circuit positive and ground on the PCB and potentially (pun intended) allow capacitors to discharge and should not generate too much heat if they are small caps.