NSklavos

A MAX1491 is a self contained DC Voltmeter that can drive an LCD display to 2000 counts. Also, here in the US, you can buy inexpensive DC panel meters for about $10.00-$15.00 each.

I have used the following circuits to null out offsets on wheatsone bridge circuits. The first circuit just puts a resistor in parallel with one branch of the bridge allowing any offset to be adjusted out. R Offset value can be calculated by figuring out parallel resistance needed to compensate for the bridge offset when the pot is at either extreme of it's range (i.e. R Offset will be either tied to +V or -V/Gnd). The second circuit just uses an op amp in a voltage mixer configuration. The potentiometer can be any value (10k ohm works OK). R Offset can be calculated by figuring out how much offset you need to adjust for and the votage gain of the op amp.

I have used the following attached schematic using a 7486 exclusive or (XOR) chip. It is basically a digital frequency doubler. It relies on the propagation delay of the second and third section to provide an output pulse. With Pin 1 High, the output (pin 11) will be High with a negative going pulse. With Pin 1 Low, the output (pin 11) will be Low with a positive going pulse. Pin 2 is the clock input or a hi/lo switched pulse. The output pulse is pretty narrow so you may want to follow it with a 555 timer or one shot chip to get a desired pulse width out of it. You can probably use a cmos chip like a 4070 for the XOR also, I believe just the pinouts are different.