Ta da!

Today I'm releasing a preview version of what I've been working on for the last couple of weeks--a version of OpenStim capable of driving up to 5 electrodes at the same time with fully independent current regulation for each electrode.

OpenStim accomplishes this using time-domain multiplexing. Essentially, electrodes are switched on and off very rapidly, so that only two are connected to the circuit at any given time. By swithing between pairs of electrodes at a high frequency, OpenStim can safely stimulate multiple areas of the brain at the same time.

Supporting multiple channels is a big step technically, and a lot of the underlying software has been overhauled and made more robust. You probably won't need to make many changes to use old protocols with the new version, as it's been designed to be completely compatible with single-channel imprint files, but the new software is significantly better and will probably serve as the base for the beta version).

One thing that has changed is the hardware configuration. In this version, pins 4-8 all act as programmable channels. The "default" channel, which is used by the diagnostics,calibration, and anything that doesn't specify a particular channel, is on pin 8. The programmable resistor and current sensor should remain attached to pin 2.

A more technical and in depth description of the hardware and software involved can be found here. You also might want to take a look at the latest hardware schematic

Keep in mind that this feature is still not under development, and some things may not work properly in this version. If you can't live with that, don't download it. In particular, it's safe to assume that the custom waveform and sham modes won't do what you want them to do.