I'm working with a new sensor I picked up a few days ago and was wondering if I could use a Lithium Ion or Polymer battery vs the TWO 9V batteries the circuit is described to use.
Thanks guys. Any way I can circumvent using two batteries vs. one? Not sure why this circuit was designed with two batteries. Doesn't make sense to me.
Would appreciate some links to a battery I can use.
first, you need make decision which one you need, Wh/kg or Wh/dm3, first one is weight and second one is size.
if you ask Lithium Ion or Polymer battery, they have same Wh/kg and Wh/dm3 for Lithium Ion or Polymer battery.
second, Muscle Sensor use 2 Ops;- AD8221 and TL084.
current consume of AD8221: 1.2 mA
current consume of TL084: 2.5*4 mA=10 mA
total is 12 mA, could reduce current by replace TL084 to low power version.
third, how long do you need sensor last per battery change or charge? by use alkaline one will give you 47 hours. The massive Polymer Lithium Ion Battery - 1000mAh 7.4v will give you 83 hours (3.5 days per charge).
My goal is weight and size. Need the circuit the work for a few hours. So the smallest power package works. I'm not too seasoned with batteries and how to connect them to this particular circuit, so would greatly appreciate some help.
dakrisht:
Can't grasp why the circuit was built to use two massive 9V batteries vs. a small LiPo or Li-Ion?
That is the way normal analogue electronics works. If you are doing something like picking up tiny voltages you need a solid ground referance, then voltages go either side of that.
You can use a single supply and create a vertical ground by using two equal size resistors, say 1K but that is prone to interference pickup and with this application you are very suceptable to it.
So using a split supply is the way to make it work and not the perverse decision you think it is.