Just fried one more arduino disconnecting the sensor with the power on
Dew Controller Feature Rich
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After a full night of imaging, with the first light, i pulled the sensor stereo connector out of the socket with the power on. The screen went immediately blank, and Arduino does not boot anymore.
Reading http://forum.arduino.cc/index.php?topic=101016.0 after suspecting that the stereo connector could be shorting the power to data lines when pulling out the plug, there are more people who say that stereo plugs momentarily short the leads when the jack is inserted/pulled out.
I guess i need to look for another connector, because i am sure this will happen again
Yes, that is why there is big red warning text in documentation re this exact issue. The temp sensor uses 5v, Gnd and Data, so yes, something might sustain damage if you plug the sensor in or remove it when power is on. Thats why the warning is there.
BUT
However, the way the sensor is connected (tip = data) when unplugging it or plugging it in, it is near impossible to short the data line of the Arduino to VCC. Even if it did, that in itself should not damage the Arduino anyway.
What will happen is that VCC and GND will probably be momentarily shorted. This could have blown the fuse or a pcb track. But is very unlikely to blow the Arduino.
If you have a voltmeter I would check these first. Plug in USB and check that there is 5V on the Arduino 5V pin. If not, trace back from there.
If using 12V remember that the 5V on the arduino comes from the onboard voltage regulator, so you need to check VIN is at around 11V. If not check back from there.
If there is 5V on the Arduino 5V pin, then its probable that the arduino is dead (especially if there is no red pwr led on the nano/uno).
You are correct in that a different connector is the better solution.
Ive just ordered these from ebay to see what they are like.
Ive also been guilty of removing cables when power is on - but have not had any failures so far.
http://www.ebay.com/itm/3-Pin-Male-Mini-XLR-Audio-Microphone-Chassis-Mount-Standard-Socket-Connector-Set-/161517964108?pt=LH_DefaultDomain_15&hash=item259b388b4c
http://www.ebay.com/itm/3-pin-Female-Mini-XLR-Audio-Microphone-connector-TA3F-/191092226559?pt=LH_DefaultDomain_0&hash=item2c7dfbf9ff
Ive ordered 4pcs, for the dew controller, and the other 2 for myFocusers.
I was looking into the XLR connectors and mini din connectors as well. i am also thinking abount something along the lines of http://www.ebay.com/itm/221614705449 (although cutting a rectangular hole is quite a headache), since i want to have a few more outputs for peltier dslr cooler setup (that's 1 more sensor and 2 more fans that i need to connect), this would take less space and be less expensive.
The RJ11 looks ok, it comes up with $10+ shipping for me though.
Did you manage to find the time to troubleshoot your issue?
Ive only ever blown 1 Arduino, and Ive had a lot of mishaps, plugging and unplugging sensors with power on, connecting componets live, shorting things out etc. The one I blew was related to too much voltage on VIN (a lot of the chinese clones apparently will not handle 13.8V car batteries) hence the change to using VIN protection circuit. It was completely dead, no leds lit up at all when connected to usb 5V.
The arduino lights light up when i connect the USB, but the usb communication is dead and the communication to the LCD as well. Haven't troubleshooted beyond that yet.
One thing that is suspicious to me, now that i think of it, is that this is the first time i was setting the whole system up on a mount (i was running test with just the reflector tube on a table before), and i got a few static electricity discharges when touching the tube at the beginning of the session. Everything (mount and my pc) were powered through an inverter feeding off a 12V 120AH battery, the arduino was not even connected to the 12v because the dew point was 15C below ambient, i was just monitoring the temperature of ambient and scopes. I am wondering if the temperature probes that touch the scope tubes could be conducting some power into the tube, mount, whatever, and that could have aggravated the issues (like large ESD discharging into the arduino when i unplugged the temperature sensors )?
the mount was powered off 12V transformer connected to the same inverter, no ground lead. the laptop power brick does not have a ground lead either, so could these potentially be 2 different "grounds" ?
Perhaps the firmware loader got corrupted - the lights can light up but the usb would be dead and thus the lcd as well (as it would not be running a program).
Do you get the backlight on the LCD?
This happened to me once and I was able to reload the bootloader.
I would try reloading the bootware loader -
See
http://www.instructables.com/id/How-To-Burn-a-Bootloader-to-Clone-Arduino-Nano-30/?ALLSTEPS
or
https://learn.sparkfun.com/tutorials/installing-an-arduino-bootloader
I doubt that the probes are conducting power - the metal case is just that, the temp sensor ic fits inside the tube and the ones I have pulled apart had no connection to any of leads to the metal enclosure. Though who knows with some of the chines probes? I just havent seen it. You could test each lead and the metal case with an ohm-meter and measure its resistance (I have tested all of mine, are fine, no resistance). Its probable you got some serious voltage spikes through ground or power to the Arduino.
Yes, ALL GROUND LEADS SHOULD IDEALLY BE CONNECTED TO THE SAME POINT TO AVOID GROUND LOOPS OR GROUND POTENTIAL DIFFERENCES.
If you experienced static electricity touching the scope tube then that is a really serious issue that could potentially blow a lot of things up. It indicates the ground power to the scope is NOT at ground (normally the power ground is connected to the metal housing of the mount so all metal beings of the mount will be at ground potential). Potentially that could be 400+ to 1000+ and yes, that will blow stuff in the twinkle of an eye. If you can feel it then its pretty much an unsafe place for electronics nearby.
I have a metal pipe that goes about 4 feet into the ground beside the observatory, then a thick solid copper wire (about 4' long) that feeds into the floor at the base of the pier to which all grounds from each PSU are connected.
Just another thing
if you plug in the arduino to your laptop, is a com port recognised?
If it is, but the Arduino IDE cannot upload new firmware then its a bootloader issue
If there is no com port found when plugged in it can still be a bootloader issue, but more likely a dead arduino.
I have had 1 arduino where there was no com port found but reloading the bootloader (using a spare Arduino uno) saved it from the bin.
The PC does not do anything when i connect the arduino, so i am guessing its dead. My suspicion was that the inverter was touching the metal in my car (and it was), i did not get any spikes after i put the inverter on a plastic surface. but i will examine this once more
After a lot of back and forth, I am going with RJ11 6P4C connectors. Easier and cheaper to make extension cables, and easy to crimp (no fiddly soldering). Just the challenge of making a rectangular hole for the socket (simple large drill and then use a small file I think will the answer). So I have updated the layout, PDF and parts list to reflect this. I found that soldering the Mini DIN XLR connectors was quite a complex task and it also raises challenges if the probe cable length is too short. At present, using a 1 meter cable extension lead it works fine. The RJ11 extension cables are much cheaper than the XLR ones.
The docs look good. I will do another iteration on the project when i get the xh and rj11 connectors from ebay, should be about 2 weeks