The guys over at Openschemes have hacked a set of Smart Tweezers to measure voltages. The internal DMM chip that was used in the Smart Tweezers has voltage measurement capability however it was never meant to be used. It also seems that even if you purchase one of these Smart Tweezers you should probably adjust the internal calibration pot to allow more precise measurements.

"Disassembly of the MS8910 is trivial – remove the battery screw to expose two hidden screws. Remove these, and one more near the probes and the case can be easily slid open. The PCB resides in the LCD side, held by a few plastic clips. The battery resides in the battery compartment, obviously, and is connected to the PCB by red/back wires. Be careful not to break them during disassembly. One interesting point is that the red wire (battery positive) is considered the GND terminal of the device and is directly connected to the top probe (near HOLD button). The black wire (battery negative) is considered the V- negative (-3v) supply for the DMM chip. The positive (+3v) supply for the chip is generated by the DMM IC itself with a capacitor-based charge pump. Makes sense, when you consider that a typical meter needs to measure both positive and negative voltages so a bipolar supply will be required."