Greenhouse Station

Many years ago, when I knew just enough to be dangerous, my dad had a small

greenhouse in the backyard. Being young and naive, I said "Hey, why don't I 

make something that can log temperature and humidity?". 

So I went to work, I found a very easy to use humidity sensor, a digital 

temperature sensor and some thermistors. I used a PIC16F886, which is an entry

level 8 bit 28 pin micro-controller. At the time I had just learned about how 

to use serial ports on computers, so the design also had a max232 chip. I

could write a program to talk to the board over the serial port. This 

would allow me to gather temperature and humidity to store it for graphs and 

other things.

As I've said in the past, I always hate having to deal with powering things.

This led me to design the device to be located inside, with a long LAN cable

reaching outside that would connect to the sensors board. Unfortunately,

the sensor board was lost during the many years it was sitting in the 

greenhouse.

Every project needs a cryptic initialism, acronym or codename to make it

legitimate, so I named mine SAGA. I honestly cannot remember what it stands for!

Something about sensors and greenhouses.

Here are images of the final board.

This was the first board I fully assembled and layed out on protoboard.

I was pretty happy with how clean it ended up being, with no jumper wires 

on the top.

I powered it with four AA batteries, which connected to a simple two position breakaway header, sort of like this one on digikey. The voltage was regulated by an LM7805, seen with the machine screw sticking out of it in the above picture.

Finally, the bottom of the board. I'm still satisfied with how well I was able

to lay out the wires, it took a long time but was oh so worth it. I think I salvaged wires from a cut up ethernet cable. They are cheap and provide 8 x 24AWG stranded wires!  

Here is a side view, so artistic. During the time I was thinking about 

how to best get the data back from the sensors, I thought "Hey, LAN cables

are cheap and have 8 wires, why don't I use one?". That's why you see a 

hacked on RJ45 connector here. I had to bend each lead of the second row so

they would fit in the 0.1 inch protoboard. As it is, the footprint of the

rj45 connector is 0.1inch, but the second row is offset by 0.05 inches.

Now here are some more pictures...