If you don't want to read any pointless chatter you can feel free to skip to page two.
You have been warned.
Over the summer I once again was looking for a fun project, that I could learn something from (AKA mess up twenty times, and correct my mistakes then try again). As I walked outside it was burning hot, my best guess was 451 degrees Fahrenheit (yes that was a reference) or for everyone outside the United States 232.778 degrees Centigrade (The joke doesn't quite transfer as well). Anyway, on that day I knew I
had to know the temperature all the time when I was outside. So, I went online and looked for outdoor thermometers. As with my desk
none of them were what I wanted and I thought I could make one myself. So, I started on the project off and on. In all it took me about 3 months (Most of which it just sat there) to build my thermometer. In the end I am pretty happy with the results. There are a few thing I would like to change if I was going to do it again, all of which will be listed in the different steps as there are relevant. But, in the end I had what I set out to make, and it even looked good. :)
Disclaimer: I have no formal education in either woodworking, electronics, or programming I am completely self taught in all three areas. Thus, I cannot promise that my work will follow any conventions of the three. And for anyone reading my programming, I know it is very inefficient and if someone would like to rewrite it for other I would be happy to upload it will give credit to you.
Safety Disclaimer: The use of tools can be dangerous, please use common sense. I cannot be held responsible for any injury due to misuse of tools. That includes injury to animals that may be in the vicinity of your work space.
Answers for the Make to Learn Youth Contest
What did you make?
I made a digital outdoor LED thermometer. The thermometer comprises an AtMega328P which analyzes the one wire digital temperature sensor, which is then displayed using a custom 2.1 seven segment display (two full digits and a one) made by 10mm LEDs. Each controlled by a MOSFET mounted on a custom PCB. In addition to the electronics, I also produced a suitable wood enclosure made from multiple boards of poplar and plywood. Finally, I used the Arduino IDE to write code for the AtMega328, I then uploaded the .Hex file created by Arduino to the chip with an ISP. If you would like to read more of the reason for the project the first paragraph provides a dramatized account of my choice to make the thermometer.
How did you make it?
After searching the web trying to find a outdoor thermometer I liked I came up empty. So I decided to build one on my own. (In hind sight it would have helped to get someone who knew what they were doing to help). As I started out I had a set plan to take a precut circular table lazy susan top and route out the back. Well that didn't work which describes much of the project. I would plan for a certain path but many times I had to rewire/recut/reflash to finally get a working thermometer. More of detail is available on the third and fifth step.
Where did you make it?
I did all the major work on the project at my house. All the woodworking was with my limited tools in the garage, the soldering was on the kitchen table until my mom kicked me off. While all the actual work went on at home, much of the deign went on during school when I had free time in classes or was just bored I would sketch the redesigned circuit or think about a better way of constructing the enclosure.
What did you learn?
The biggest challenge for me was designing and building a circuit that could drive multiple segments of LEDs which required a higher current and power than the AtMega could provide per channel. The biggest surprise to me was how well it actually came together in the end. I had some what expected to finish it half way and then give up after getting one part to work, but I finally got all the parts working together. After was all said and done the proudest part of the build was the PCB I designed, after soldering up the whole circuit on proto-board I decided to design and have manufactured a PCB which I think turned out beautifully. If I had to do it again I would probably spend a little more time on the enclosure because I have some ideas on how to improve its function and performance.
More information is spread through out the instructable which answers the questions. These answers are just a summary of the information.