Raspberry pi Zero W + Arduino Nano headless Heater Meter problems


 
Hello, Im trying to put together a small HeaterMeter with a Raspberry Pi Zero w, Arduino Nano and a Maverick PR-005 probe.
I'm having trouble with the Raspberry pi resetting and coming back up in AP mode. I believe i could possibly have a wiring
issue with the probe wiring because it only does it when the unit is powered down and probe setup plugged into the breadboard and powered back up.
The other thing I was wondering is if the Pi's 3.3 volt line can't handle running the Arduino Nano and the probe at the same time?
I Have the probe wiring 3.3 volt line to 100k ohm resistor to center pin in probe jack with in split with 10k ohm resistor in the line to analog input with a 0.1 u capacitor to ground.
Also Im a little confused on how do I include pictures in these post from a mac?

Thanks,Adam.
 
The only thing I can think of is that the overlayfs, where all the changed configuration is stored, is getting corrupted and somehow resets. I can't seem to reproduce this. I actually tried unplugging power fifty times in a row at various stages of the boot sequence and never had the configuration reset. I'm not saying it is impossible by any stretch, but the fact that you get it so consistently indicates there's something weird going on here. You'd probably need a monitor to see the messages on the screen when it boots the first time with the reset configuration to see where along the process something new is happening maybe?

The Nano should draw <15mA and the probe pulls <1mA (unless you manage to short something) so there should be no problem with the Pi sourcing that from its 3V3 pins. What about your 5V power supply, is that giving the Pi enough power?
 
Hello, the Pi Zero W is being Powered by a CanaKit 5 volt 2.5 amp micro USB adaptor, a few days back I was messing with a Adafruit P1778 analog type K AD8495 breakout but Im unable to get the readings right, I saw in another thread they need quite bit of modifying to make them work. The Pi did not reset during the messing with the Ad8495 breakout only when I connect the probe wiring and repowered the Pi. I have 3.3 volts to a 100k ohm resistor to center pin with a 10k ohm that splits off that line an goes to data line a 0.1 u cap between data and ground but my sleeve side is also connect to ground which I believe I messed up?
 
I'm not sure you'll be able to get that Adafruit AD8495 to work because it has a +1.25V offset which adds 250C to the output. HeaterMeter can only compensate for +/-127 degrees so that's not nearly enough. You can disable the TLVH431 chip on the board and tie the AD8495 input to ground to remove it's offset and it will work with no offset in HeaterMeter.

I can't follow your description of how you have everything connected to the thermistor, but I think the pictures you emailed me were right at the time. The sleeve side of the probe is supposed to be connected to ground though so that sounds right. I think your 100k resistor is wrong though, it goes between the thermistor output and the 0.1uF cap. It would make things a lot easier until you get things working to remove the 100k and 0.1u cap though. It only filters the analog. Once you get past the initial hurtle of trying to get values into the microcontroller, you can increase complexity by adding it back in.
 
Hello, experimenting on the Pi now with an Arduino Uno. Still seem to be having an issue with it reset to AP mode and rebooting all the time. Powered both units with a micro usb breakout and getting 5.12 volts. I have a level shifter in between the uno and pi uno TX to shifter to pi. I have been using Etcher to flash the SD cards with a download I downloaded earlier in the week.I wasn't sure if Etcher was good to use or not? Ive overwritten the cards a few times because of the reset kicking them in AP mode. Maybe try fresh download and flash with win32?
 
Well that Etcher program is pretty strange, I've never used it before. I do like that it works on compressed images, which is a feature that Win32DiskImager has had on their todo list for like 5 years now. When I tried it, it said the first burn I did couldn't be verified. It seemed to work fine in the Zero. I tried flashing a second time and it verified properly. I am not a fan of the app over diskimager, but it does appear to do the job.

If the Pi boots and works, then the image is fine. I don't know what's happening that's resetting your filesystem, but it seems unique to your setup. Are you making sure to take ESD precautions when touching the devices? Maybe you're shocking it. Do you have other pins connected? Maybe one is pushing 5V at some point. It does seem odd that only the writable filesystem is getting mangled though. Have you tried a different SD card? It is possible you're getting write errors. The only thing you really can do is hook it up to a monitor all the time and keep you eye on the console to see if there are error messages happening.
 
Ok, Im not sure what to think, I've tried about everything even tried it with a Pi 3 and the nano and it runs fine until I power down and hookup the probe wiring. I ran the Pi 3 for 2 hours with nothing connected besides the Nano with TX RX 3.3 power on its 5 volt pin and a level shifter between Nano's RX and Pis TX pin and all was good until the probe wiring was connected Then it continues to crash until the probe wiring is taken off. Im wondering if I need to power the Pi and Nano from two different power supplies? Im using Sandisk SD Cards Ultra plus class 10 same as in I'm full HeaterMeter. I see the Base board has a lot of Caps on it wondering if it's a noise issue resetting or frying the Pi?
 
Eee I wouldn't think you need different supplies. Have you checked all the connections with a multimeter to be sure you don't have a short somewhere? You can also check the voltages. With no probe plugged in you should see 5V=5V, GND=GND, and the wire that runs back to the Nano ADC should be 5V as well. When you plug a probe in, the voltage should drop on the ADC wire, dependent on the temperature.

The capacitors on the HeaterMeter board are for smoothing the incoming 12V, smoothing the outgoing blower, smoothing the 5V we generate on-board, and smoothing the 3.3V we generate on-board. You shouldn't have 12V or a blower, so those are out. The 5V is generated somewhere else, and you're not using 3.3V, so that means probably good with no capacitors. You do have GND on the Pi and GND on the Nano connected as well right?
 
Yes, the grounds are connected. Does the Nano need 5 volts or 3.3 since its a 3.3 volt nano? Also probe powered by 3.3 for the nano? I have the setup with the Uno powering the uno and pi both with 5 volts with a micro use breakout with level shifter between them. they both only trip after the there powered down and single probe connected and powered back up then they run for a bit and just keep rebooting.
 
I don't think there's such a thing as a 3.3V nano, they're all 5V. You can power them with 3.3V if you plug into the 5V pin (assuming they're all made the same, which being knockoffs there is no guarantee). If you're running at 3.3V then you don't need level shifters. If you plug ANY 5V SUPPLY INTO THE NANO while running it at 3.3V then you're going to have a problem, possibly in the destructive sense. This includes the USB port.

Sounds like what you're seeing is a voltage regulator somewhere overheating due to a short and when it does that it turns off for a second then turns back on and repeats. Feel around on the Pi / Nano / etc for anything getting hot. If you are mixing 5V and 3.3V then 5V can actually backfeed into the 3.3V regulator output and cause glorb knows how many problems so watch out for that.
 
Sorry, I saw the info on the Nano sheet it said version 3.0 my bad. Powering Nano at 5 volts now with level shifter in between nano and Pi. Powering probe at 5 volts still trips when running with probe. Probe pulls between 3 and 5 ma. I'm powering everything through the Pi 3 not sure if thats what I need to do? I'll send some pics.
 
Hello, I didn't feel anything get hot. I don't beleive the Pi 3 has a voltage regulator on the 5 volt pins just 3.3 volts? I was thinking maybe it's tripping the 2.5 amp resettable fuse? Everything is fine until I add the 10k ohm pull up from 5v to the analog input. When I was messing with the other rig with the Pi Zero W and the Arduino Uno they were both powered through a USB micro breakout and the software still went Bananas and kept resetting when the Maverick probe and jack was added. Something almost has to be wrong with the probe wiring? Would resistor values have to be changed for 5 volts? They both run fine when the AD8495 from Adafruit was connected, I just haven't got brave enough to mess with the offset chip yet. Maybe thats the way to go though.
 
The resistor is the same on 5V and 3.3V so that's fine. But you say that if you just take 10K resistor and run it from +5V to A5 everything starts going crazy, no probe involved? That I do not understand at all. I thought we might be on to something when you said you got 3-5mA current draw which is way wrong but not enough to cause a problem, but in your photos it is 0.04mA which is closer to the expected value.
 
Just a quick test I did, which works as expected.


From the Pi:
The orange and yellow wires are my +5V, so you won't have those.
The white and graybrown are 3.3V and GND (to +5V and GND on the Nano)
Blue and Purple are RX/TX running right to the Nano
- Confirmed HeaterMeter webui communicating and probes floating all over-

On the Nano:
The 10k resistor goes from +5V pin (actually 3.3V) to A5. Confirmed probe reads as Off in HeaterMeter webui.
The little brown wire with the black alligator clip is connected to the shield of the probe.
If I take a red alligator clip and clip it to the probe connector's "tip" and to the left side of the 10k resistor, it reads room temperature in HeaterMeter webui.

I do not have one of those level shifters so I can't test running the Nano at 5V.
 
Yes, My bad the probe pulls 0.04 ma. I went and placed a 10K ohm from the 5 volts to A5 and powered up and she goes crazy and resets and keeps rebooting. Is the Nano you are using a real Arduino Nano? The only difference is is my resistors are 5% 10K ohm. If I pull the A5 to Ground it reads off on the HeaterMeter.
 
It is a bench power supply, but I never saw the current go over 500mA (normally 280mA), although this is a Pi B+ not a Pi 3. However, the power supply power rating is not an issue. There is something else wrong but I have no idea what it is. Have you tried it on 3.3V like I have it, without the level shifter?
 

 

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