I don't think he can do too much damage brain wise - the effects of the noninvasive transcranial magnetic/direct current stimulation only last for a few hours a

I don't think he can do too much damage brain wise - the effects of the noninvasive transcranial magnetic/direct current stimulation only last for a few hours anyway. The bigger issue is potentially getting skin burns by not getting the circuitry hooked up correctly. Or maybe frying your electronic gadgets if you have a magnetic stim device. I guess maybe you could theoretically trigger seizures if you have epilepsy, but in that case you'd be seeing a doctor regularly anyway and wouldn't have to DIY these things.