ARTIFICIAL SENSES 

Why should we be limited to the spectrum we're born with? 

Post-Apocalypse, everyone will want to own a geiger counter to see if the fallout is going to get them. Why in the world can't we put a geiger patch on each of our shoulders and be hypnotized into believing that we have Geiger ears on our shoulders that can "hear" radioactivity. 

Implant them young enough and the brain would wire itself to accept the input from the sensors are part of "the senses." 

This guy is kinda doing that 

DIY Headphone Implant with Coil

So what could we sense? 

Galvanic Skin response in our fingertips to see if someone is lying
Carbon Monoxide / Carbon Dioxide / Smoke detectors
Barometric pressure - our own weather station
Echolocation / Radar Pings ?

Ears / Eyes 

Since there are many flavors of radioactivity that are harmful to humans, the sensors would be like ears, with thousands of On-Off gates that tell which frequency was present, and intensity guages that tell how "loud" it is.

However for some frequencies you would want an array of pixels so that the sensor could create an image, like an eye. 10kx10k sensors in the palm of each hand, sensitive to the band used by Radiotelescopes, and you could be your own observatory.   (how would you focus them? not sure) Besides Infra-Red and Ultraviolet and Xrays, I can't think of other useful frequencies.

The point of this is that there is only so much space in your eyeball - all of this is doable with Google Glasses but you will end up walking into lampposts.