Power up from VIN issue

[perky]

Now I'm confused.

Can you tell me exactly what you have and exactly how are they all connected together? Have you got an arduino? An arduino uses 5V logic on its I/O pins BTW and a moteino uses 3.3V logic and as far as I am aware not 5V tolerant.

This is the bit that I'm confused about though:

I started with fresh Mote #3 and connected my CO2 sensor only.  It could not be powered by the 9V battery, yet it worked fine connected to USB.

The sensor you quoted requires a +5V supply, so presumably is that coming from the +5V rail on the arduino? If you only connected the CO2 sensor and nothing else to your moteino, how are you powering the +5V of the sensor?

That arduino +5V rail comes either directly from a USB connector, or from the output of a +5V regulator which is powered by Vin and which has to be 7V to 12V (and if it is powered from Vin there is a FET on the arduino that automatically disconnects the USB +5V from that rail). My guess is the regulator provides much better regulation on the +5V than the USB which is why they recommend using 12V.

Mark.

[odiephd]

Mark,

I have Moteino RFM69HW version (no Arduinos).  The sensor can be powered by 3.3V/5V according to website but the spec sheet says 5V.  It works great when I power the Mote with USB power. 

In addition to the C02 sensor, I have the SHT31 temp/hum sensor, and a photoresistor.  All are connected now, powered by USB through the moteino and it streams data beautifully to my Pi gateway which has the MoteinoUSB attached. 

(The part you said was confusing) If I wire up the CO2 sensor only with the moteino and power it with USB power, it works great.  But, if I try to power it with a 9V battery through VIN, it does not work.  It says it only draws <85mA so I don't understand why it can't work with 9V battery.

Thanks for your help!

[perky]

OK. I can find no reference to being able to power it from 3.3V on the website (it mentions 3.3V or 5V selectable for IO signalling, but that's a different thing). Unless you can point me to where it explictly says this can be powered from 3.3V I think this device requires a 5V supply.

The other thing worth noting is you're taking at least 85mA from the 3.3V regulator on the moteino, which has 9V input from the battery. The regulator is dissipating (9 -3.3)*0.085 watts, i.e. about half a watt. This is a MCP1703 in what appears to be a SOT-23 package so it'll get up to 168 deg C above ambient according to the datasheet, that's some way above max working temperature. It would not surprise me if the regulator is continually thermally shutting down, that could be your reason why it doesn't work.

Mark.

[Felix]

This is starting to get stranger. The thread title suggests this is just the Moteino, but its clear that's not the case now.
@odiephd I want you to try a unmodified moteino only, with nothing else attached (well headers are OK), load it with a blink sketch (no sleep, no libs, nothing else). Program via FTDI then unplug and power from 9v batt. Let me know if the LED still blinks.

[odiephd]

Felix,

Sorry I think you missed some of the info, probably because I've been posting my troubles a lot.

I did start with the node_test_example sketch with nothing connected to the mote, and it worked perfectly every time.  Then, I started adding code back to try and determine if was my code.  I added line-by-line checking to make sure it worked off battery each time for the SHT31 temp/hum sensor.  I integrated the temp/hum sensor and had no issues at all powering it from USB or battery.

I proceeded with same mote to add the code line-by-line for the CO2 sensor.  I added the #include library stmts and had no issue.  Once I added the line to establish mySensor with the library, that is when it would not power up using the battery.  That's what has lead me to believe I have a power issue.  But, I don't understand why because the spec sheet says it draws <85mA. 

To make my problems more interesting, I tried to get the mote to work again.  I couldn't get the mote to work off battery even after removing the line and re-uploading the sketch that worked moments ago. It worked powered off USB.  I even uploaded the node_test_example on the mote and tried to power off battery but no.   To make it more confusing, it sat overnight, and the mote worked perfectly with the node-test example.  Actually, two of them that I was using for testing behaved the same, and both worked after they sat overnight. 

Yesterday, I started with a fresh mote and node_test_example.  All worked fine.  I added the code again for the CO2 sensor alone (not with the SHT31 as above).  It had the same problem at the same line of code, establishing mySensor using the library.  CO2 sensor was attached in all cases.  It was also consistent in that I couldn't get the mote to work off battery power, no matter what I did....like DTR-GND short, RST-GND short.   It has been sitting overnight and I am just getting started this morning. 

Currently, I have a FTDI/USB powered mote with the SHT31 (i2C), CO2 sensor(I2C), and photoresistor (A0) integrated and streaming data to my Pi Gateway/MoteUSB.  It ran overnight flawlessly.  I say this because I am made some great progress, and I am very excited about using Moteino as the basis for my project.

Let me know if I can clarify anything else.  Most of all, thank you to everyone for your time!
Jim

[perky]

I suggest again that it's the regulator on the Moteino getting too hot and thermally shutting down. With USB you only have 5V going into the regulator so power dissipation is much less than with the battery which is 9V. This would explain why it works up until the sensor is turned on and starts to sink 85mA, and why it works with USB and not the battery.

Mark.

[odiephd]

Ok....that is a great theory.  A couple days ago I ordered parts so I could power everything with 5V/1A cube plugged in the wall using mini-USB connector to power sensors and mote, and not use the mote to power the sensors.  I am just waiting for parts.  Will revert back with outcome.

Thanks again!

[Felix]

I suggest again that it's the regulator on the Moteino getting too hot and thermally shutting down. With USB you only have 5V going into the regulator so power dissipation is much less than with the battery which is 9V. This would explain why it works up until the sensor is turned on and starts to sink 85mA, and why it works with USB and not the battery.

Mark.

Totally....