I've designed an analogue front end for EMG signals that I want to turn into a PCB. However currently it runs off of two 9V batteries which makes the end product quite large and heavy. I was wondering how I would go about changing my design (or components) to a single battery supply?
Here's a picture of the the design(I apologise about splitting the circuit picture it's too big to display as one!) I use TL072's for op amps and an ina129 for the instrumentation amp: