Powering an iComSat GSM Shield and Gear Motor using LiPo (Lithium Polymer) Battery

Discussion in 'The Projects Forum' started by macdonaldtomw, Mar 26, 2014.

  1. macdonaldtomw

    Thread Starter New Member

    Mar 26, 2014
    I have an iComSat GSM Arduino Shield (based on the sim900) and a gear motor that I am planning on using with a Teensy 3.1 microcontroller. I'd like to power the whole rig using a 2000mAh LiPo Battery Cell. The datasheets for the battery and gsm module are attached.

    So I have:

    Teensy 3.1 microcontroller Vin= 3.4 - 4.5V
    GSM Shield | Vin=9-20V _ Iavg=500mA _ Ipulse=2000mA
    Gear motor __ | Vin=6V _ Ifree=70mA _ Istall=1600mA
    LiPo Battery __ | V=3.3 - 4.3 V _ Imax = 2C = 4000mA <--somehow I doubt this... more like 3000 mA probably
    My question is which of the following courses of action should I take, and are there alternative courses of action that I haven't thought of yet?

    1. Use boosting circuits to boost the battery voltage up to 6 V and 15 V for the gear motor and the GSM module, respectively
    2. Use a higher voltage battery source (i.e. 12 or 15V) and use voltage reduction circuits to limit the voltage seen by the servo and microcontroller.
    3. Get a sim 900 GSM module on its own (i.e. not integrated into an Arduino Shield) and use it directly with the battery (the sim900 on its own needs 3.2 - 4.8 V). I would still use a boosting circuit for the gear motor.

    What's the most energy efficient and robust solution? Or is there another solution I haven't though of?
  2. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    How long do you require this device to operate on battery power?
  3. macdonaldtomw

    Thread Starter New Member

    Mar 26, 2014
    I plan on having this unit turn on for about 10 seconds, every 3 hours or so.

    It only needs to be able to send a user-entered PIN # and the cell tower/signal data to a remote server for tracking purposes. Then it waits for the server to respond with a text-based command such as "clear", or "hold".

    I have attached a pdf the communication protocol schema I plan on using to this post.

    The battery will be recharged via a nominal 6V bike dynamo which will run approx 30 minutes per day (at more like 3 or 4 V), which I figure should be enough to keep the battery juiced!