My project is to connect Doppler motion detectors HB 100 and/or CDM 324 to a Raspberry Pi. I an searching for an op amp that will enable me to amplify the microvolt signal to accurately time an event. For prototyping I am using Python. Any suggestions would be appreciated. Thanks

 

MCP6001
How fast of a signal?
Here is a low voltage, rain-rail amp.
Watch there are too many different pin-outs.

 

ronsimpson, Thank you for the suggestion. I am researching the MCP6001. The data sheet is not really helpful.
I will be sampling the output of the Doppler every 20 milliseconds and the output is in the low millivolts. The sinal has to be strong enough the trigger a Raspberry Pi input pin from zero to HIGH (3.3 volts)

 

The MCP6001 or any R-R input/ R-R output opamp is simple to think about. Most will not work if the inputs get near the supply voltages. But R-R is Rail to Rail so the inputs can be at any voltage from 0 to 5 (in your case). I looked for a 'low voltage' part because you do not have 12 volts. I also picked a part that can pull down to 0V well and pull up to 5V well. (I forget you want to use it at 3.3 volts, it will work down to 1.8V)
I picked a part that has a gain bandwidth of 1mhz. (if gain=1 bandwidth =1mhz, if gain=10 bandwidth =100khz, if gain=100 bandwidth =10khz)
There are many parts like this. This might help you understand my thinking.