LiPower Shield

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Joe WeatherBalloon
Posts: 2
Joined: Sun Dec 24, 2017 10:23 am

LiPower Shield

Post by Joe WeatherBalloon » Sun Dec 24, 2017 10:51 am

Greetings!

I've been using the LiPower Shield to power an Arduino Pro Mini. I connect a 3.7 volt 850 mAh LiPo battery, move the switch to ON, and the power light glows red. The Arduino program starts and everything is as expected.

In between the LiPower Shield and the Arduino Pro Mini (which is mounted on a ProtoShield Kit board), is the Ardumoto shield. I wanted to extend the built-in indicator (I/O pin 13) so I connected 13 from Arduino Pro Mini to 13 of the ProtoShield Kit. In the stack, 13 connects to DIRB on the Ardumoto shield. I placed a 1k resistor and LED on 13 of the Lipower Shield and connected the other end of the LED to ground. When I moved the power switch to ON, the power light did not illuminate immediately. It slowly brightened and then dimmed. I thought I smelled a burning capacitor (possibly the 22uF after the boost circuit).

Might you have some ideas why the Lipower Shield has changed behavior? From the present behavior, might I consider the Lipower Shield inoperable?

Thanks!
Joe

paulvha
Posts: 270
Joined: Sat Nov 11, 2017 2:39 am

Re: LiPower Shield

Post by paulvha » Tue Dec 26, 2017 4:15 am

normally a capacitor will only be damaged because of over voltage. I would not expect that. however it could be that you created a short circuit and then something might get overheated and damaged.

I tried to follow your description, but which build-in indicator ( I/O pin 13) you refer to? Is that on the Arduino-promini or the ardumoto?

Looking at the code and schematics: DIRB is an output for to drive the motor direction. during initialization in setupArdumoto() it is set LOW. if you now connect a plus voltage from the indicator, you have a short circuit. You might have damaged the D13 output from the ATmega 328.

Joe WeatherBalloon
Posts: 2
Joined: Sun Dec 24, 2017 10:23 am

Re: LiPower Shield

Post by Joe WeatherBalloon » Tue Dec 26, 2017 11:06 am

Thanks for the quick reply!

Sorry for the confusion - I refer to the I/O pin 13 on the Arduino Pro Mini.

I wondered about the Arduino also. I powered it from the programming cable - that is, not using the LiPower Shield and non connected to the ArduMoto board. The LED on D13 glowed as expected and it drove a second LED that I connected to the Arduino. I'll continue to monitor it as I move forward with resolving this issue. I removed the connection from the Arduino to the Ardumoto board on D13 as I did not intend to use DIRB; that was a design miss on my part.
I have an older version of the Ardumoto board so the DIRA and DIRB are inputs to designate the direction of the motor. In practice and using only the A side of the board, this has been successful in driving a Cytron Technologies motor in two directions and various speeds; the Ardumoto board is wonderful!

I isolated the Lipower shield from the Arduino and Ardumoto shield - that is, I connected a LiPo battery (3.7 v, 850 mAh) and the Lipower shield is connected to nothing else. I moved the switch to ON. The power LED does not illuminate. I fear attempting more experiments might damage the LiPo battery. I'm concluding the board may not operate as designed. Thoughts?

Thanks!
Joe

paulvha
Posts: 270
Joined: Sat Nov 11, 2017 2:39 am

Re: LiPower Shield

Post by paulvha » Wed Dec 27, 2017 6:09 am

if you do not DIRB, make sure NOT the use it as output and drive it high/low from the code. Leave it as input or use another pin.

The power led is taking directly the 5V USB input, NOT the board output. So I would not have expected it to lit. If you have a voltmeter, I would measure the output voltage otherwise I would just try to connect to the Arduino and see what happens. (short :-) It that does not work, the battery could still be low and could need to be charged otherwise I suspect that the LiPower is damaged.

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