I have encountered a hard to pin down problem, (for me) I am wondering if any one has seen something similar to this or has any ideas for a remedy or work around.
As soon as the electron is powered it enters what my guess is a brown out cycle. The status LED is white with short flickers of off, and the D7 LED is very dimly lit blue. No code is executed.
I am building a remote ultrasonic sensor using an electron as the communication path, an accelerometer, and two maxbotix MB7040 ultrasonic sensors. This device needs to run on battery’s for a long period of time, so it spends most of its time in DEEP_SLEEP. In order to save power the ultrasonic sensors and the pull up resistors for the I2C lines have been placed on a high side switch, when the system wakes it triggers the high side switch which passes the 3.3V rail (from the electron) to the I2C bus, and the ultrasonic sensors.
So my first guess is that it is a current draw problem, even though the MB7040’s only draw 3mA and I was only testing with one. I placed an ammeter on the v+ wire of the ultrasonic sensor and powered the electron (with the included LiPo) and it work perfectly fine, what?, so I removed the meter and it went back to the brown out cycle.
After further trials, if the electron is started with the ammeter in the circuit, it can be removed and the systems continues to function fine, until it goes to sleep and wakes up again.
My guess would be there is some resistance or capacitance introduced by the meter that is fixing the problem, but before I start adding random components I am curious if anyone has seen something similar. (or if I made a mistake)
Here is a rough schematic:
It exhibits the above problem when in “test 1”, but works under “test2”
Any help is very much appreciated.