Can I use a Li-Ion battery instead of a 9V battery for this application?

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.

Here is the sensor: https://docs.google.com/file/d/0B8Wy2qiwirwyNFV1dlA2T1JVZFU/edit

PCB takes three inputs: +Vs, Gnd, -Vs (see the link above)

Wondering what's the smallest battery / form-factor I can use for this?

Thanks!

if I could use a Lithium Ion or Polymer battery vs the TWO 9V batteries the circuit is described to use.

You can but you still need two of them.
The two batteries make what is known as a split supply.

Wondering what's the smallest battery / form-factor I can use for this?

It depends on the voltage, current drawn from the power rails in your application, and for how long you plan to feed the board on.

Muscle Sensor v3 spec;-

Nine-volt battery;-

u could use primary Lithium for double capacity or Lithium-ion polymer for rechargeable.

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.

Any way I can circumvent using two batteries vs. one?

Not so easy. The only way I see is to create a virtual ground then (with single battery).

Energizer LA522 9V Industrial Lithium Battery

Amazon, $8.11 & FREE Shipping

Polymer Lithium Ion Battery - 1000mAh 7.4v

Sparkfun, $5.95

pito:

Any way I can circumvent using two batteries vs. one?

Not so easy. The only way I see is to create a virtual ground then (with single battery).

Can't grasp why the circuit was built to use two massive 9V batteries vs. a small LiPo or Li-Ion?

sonnyyu:
Energizer LA522 9V Industrial Lithium Battery

Amazon, $8.11 & FREE Shipping

Polymer Lithium Ion Battery - 1000mAh 7.4v

Sparkfun, $5.95

Thanks for that but the first one is a normal-sized 9V and the second one is massive.

My goal is to figure out how to power the circuit with the smallest possible battery.

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).

once you know what you need, select battery by Electric battery - Wikipedia, You're on your own.

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.

You can use a dc-dc converter - for example from 3.7V lion/lipo to +5V and -5V (or +9V and -9V)..

http://uk.mouser.com/Power/DC-DC-Converters/_/N-5gc7

Will this work with a 3.7v LiPo battery for this circuit?

LiPower - Boost Converter - PRT-10255 - SparkFun Electronics - or - the cheaper Polulu: http://www.pololu.com/catalog/product/798

Noob question: connect this to my Arduino Micro using headers?