I have a sparkfun battery shield. and my project behaviour normally when it’s powered from the USB. However as soon as I switch to the LiPo Battery the behaviours becomes erratic. I am using the D4. D5 D6. I am wondering If any of these outputs are reserved in any way?
How are you connecting the battery shield to the Photon and do you have a link to the shield?
okay I am only using d5 and d4… still not behaving as expected… :frowning
do you have a multimeter?
Also, when you say erratic, can you say what’s exactly happening?
@mrclj, what capacity LiPo are you using (mAh)? Do you have any devices connected that use power? When the shield is not powered via USB, the battery voltage is fed to Vin of the Photon via a Schottky diode, creating a 0.3v voltage drop. This voltage drop occurs at 100-300ma current draw (total).
A poorly charged or poor quality LiPo will not produce the minimum 3.6v input to Vin required by the Photon’s switching regulator. To get the 3.6v, the LiPo needs to supply a minimum of 3.9v. As @kennethlimcp, suggests, you should measure the voltage on Vin when USB is not connected.
AHHH this maybe my problem… I also have a PIR sensor connected to my VIM and that is the think that is behaving strangely when running from the LIPO… any work around for this?
I have a PIR sensor connected to the VIM wired up like this… https://particle.hackster.io/gr1m/particle-photon-pir-sensor-and-event-reporting-268aa0
and so soon as it connects to LiPo i get a false positives from the PIR sensor
@mrclj, one note from Adafruit and depending on the PIR sensor you use:
Runs on 5V-12V power (if you need to run it off of 3V you can do that by bypassing the regulator, but that means doing a bit of soldering).
This might explain the false positives. Which sensor are you using? There are low power sensors (which @RWB has used) but they are ultra sensitive and difficult to use.
You need a PIR with adjustable sensitivity for sure. Here is one sold by SparkFun https://www.sparkfun.com/products/13968
And here is one that I saw but haven’t bought yet but looks pretty cool.
Yep I have a adjust sensitivity PIR from AUKRU. So my problem is i am powering the PIR form the VIM output which is also powering the LIPO charger. Is that correct?
@mrclj, I believe you mean the Vin pin. The Vin pin is the direct connection to the Photon 3.3v regulator and is fed from the battery through a Schottky diode as I said before. Is the Aukru PIR able to be powered from 3.3v without modification?