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Hello again.

I've put together a RedBoard-Simultaneous RFID Reader-external antenna combination as per the instructions on your website. It's now working pretty well, the only glitch is that, when I first plug it into my laptop and fire up the Arduino IDE serial monitor, it always gets stuck at "Press a key to begin scanning for tags." The only way to get past this line is to power down the component and disconnect it from my laptop, and then try again. After this, it works normally. But if I come back to the component after a little while, I run into the same problem again.

Rooting through some of the code - I'm using the Simultaneous RFID Reader code on GitHub - it seems that the problem is in "loop()". The "if(nano.check() == true)" returns false, and keeps returning false, so "loop()" just repeats over and over and does nothing. But I have no idea how to fix this! It seems odd that powering down and restarting allows the "if" statement to return true. Any ideas?

For the time being, this glitch isn't the end of the world, but I'm trying to build a sell-able product - which means that eventually it'll have to work first time reliably.


BONUS QUESTION: Will the RedBoard-Reader-antenna combination described above shut itself down if it gets too hot?
Hi Tom,

That is a weird error that I am not sure we have seen before. Just to confirm the issue, the code hangs at "Press a key to begin scanning for tags." and then regardless of what you enter in the serial monitor, it never progresses past that? Have you tried uploading the other examples to see if the issue is persistent across multiple examples or just the "Constant Read" example? Finally, even though I doubt it is a hardware issue, can you take a few photos of the top and bottom of your Simultaneous RFID Reader and attach them to your reply? Please do your best to make sure they are clear and well-lit.
Sorry for taking so long to reply. It's been a heck of a week at my end! Hopefully I'll be allowed to resurrect this thread...
Just to confirm the issue, the code hangs at "Press a key to begin scanning for tags." and then regardless of what you enter in the serial monitor, it never progresses past that?
That's exactly right.
Have you tried uploading the other examples to see if the issue is persistent across multiple examples or just the "Constant Read" example?
I didn't think of that! Unfortunately, when I tried uploading the other examples just now, the same error - or an equivalent thereof - cropped up in each of them. In those examples without a "Press a key" stage - or where I removed it from the code - I'd get either a "No response. Check wiring" or "Error reading tag" (I forget the exact wordings). Again, disconnecting the equipment from both the laptop and the power supply, and then starting again, resolved the issue.

It's also worth noting that I've actually built *two* of these RedBoard-Reader combinations, and the same error crops up, in exactly the same way, on both. I must be doing something very silly somewhere, but I don't what!

I've attached the pictures you requested.

Also, as per my last post, I do need to know whether the RedBoard-Reader has any overheating/bursting-into-flames prevention mechanism built in.

I couldn't get the
Code: Select all
thing to work, so I've just attached the images as links. ... VmZlQHNmG- ... _FttXRz7_9 ... 286ouavdYK ... 7ZuoUxP9LM
Hi again Tom,

Thanks for clarifying where the issue is cropping up and taking those photos. If you're getting the "Module failed to respond. Please check wiring." error, it might be a power issue. What are you using to power the RedBoard+M6E Shield? Also, if you have another computer available, try testing on that to see if the issue follows the computer.

Also, to answer your previous question, the M6E Nano does have a thermal shutdown feature if it gets too hot. The included heat tape should work to prevent that feature from triggering unless it is in a tight enclosure. If that's the case, you may want to look at adding an actual heat sink to the heat sink pad on the bottom of the M6E Shield. There are mounting points on the board specifically for this application.
Thank you both for getting back to me so quickly. The first-start-up fault now seems to have disappeared almost as mysteriously as it arrived.

With respect to the overheating issue: you mentioned that it ought not to be a problem, so long as the component wasn't housed in too tight an enclosure. How tight is too tight? I've attached a photo of our current setup: we're housing two Reader-RedBoard pairs in an aluminium - I suppose you chaps would say "aluminum"! - box. Will this be okay?

Is there anything we can do, in the software, to keep things as cool as possible? The device we're trying to build only needs to send out a pulse every few seconds. Could we shut the reader down for two seconds between each pulse? Would this prevent it from building up heat.
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Huh. Those are always the worst issues to have since you're not sure what caused it and what might trigger it again. If it comes back, let us know and we can try and figure out what the root cause is.

As for overheating, I do not think you'll have problems with that enclosure if you're just running the M6E's at short bursts. I cannot say with 100% certainty whether or not that enclosure is too tight but I don't think you'll have any issues with that enclosure. You will probably want to run some stress tests with the enclosure closed prior to a permanent installation, though.

As for controlling the readers to try and mitigate any heat-related problems, you can absolutely modify the code to turn the readers on/off or just starting/stopping reading. The full list of the available functions in our Arduino library can be found in the C++ File. You can either use delays or interrupts to trigger the M6E to either power on/off or start/stop reading tags if you want them to switch on and off every few seconds.

If you run into any other issues or have any other questions about the Simultaneous RFID Reader, let us know and we would be happy to help as much as we can.