Caspar Menkman

An Interview with HIH-4030

The smartass humidity chip by Honeywell.

In this first installment of interviews with sensors, the HIH-4030 Humidity Sensor breakout board will introduce itself.


HIH-4030 -

So introduce yourself.
Well er. you're slightly putting me on the spot, but here it goes. I am HIH-4030 and I am a humidity sensor.

What does HIH stand for?
I don't know. It could have something to do with my manufacturer's name, Honeywell International. And also with the fact that I am a humidity sensor.

How do you actually measure humidity?
I measure the relative humidity with my laser trimmed thermoset polymer.

(that sounds dirty, but)... eh, what?
Let's start at the beginning. Humidity is the amount of water vapor in the air.

I knew that.
Every volume of air has a maximum capacity for 'storing' water. The relative humidity is the percentage of this maximum capacity stored in a given volume of air at a given moment. This correlates to the temperature and air-pressure at that moment in the volume of air.

OK, I understand, but what's up with your laser trimmed thermoset polymer?
Well, a polymer is a large, often synthetic, molecule built up from atoms that are linked together through covalent chemical bonds.. *cough* I mean shared atoms. When a polymer is thermosetted it has been treated with heat or radiation and has been irreversibly hardened.

OK, I think I got it now. But what kind of signal do you pass on to the system formed around you?
My output is in voltt. This means that my output is easily integrated in any system. And can be used to trigger countless responses.

You know an awful lot for such a small chip.
Yeah, I am 19.05 x 7.62 mm full of awesomeness.