Arduino on a breadboard with AMT1001 sensor and seven segment display

As efficient as attiny85 may be, you can't run the seven segment library without using another chip.  So for this project, I will have the arduino display the readings of a humidity and temperature from a cheap AMT1001 sensor into a 4-digit seven segment display I salvaged from an old clock. Instead of using an arduino board, I will make an arduino on a breadboard and save the arduino for another project later on.  

Here's the detailed instruction on how to build the arduino on a breadboard. I skipped the parts for the power supply as I plan to power mine with 4 AA  rechargeable batteries. I also did not include the usb to serial board since I will use my arduino to program the atmega chip on the breadboard.
 
It is tight but everything fits on the small breadboard with no room to spare. The seven segment I salvaged was meant to display time so I just stuck a small tape on one of the dots of the colon to make it a decimal. Here it is ready to be powered.

Until now, I still can't believe how the seven segment library works. It is so clever! I thought I would at least see a little bit of flicker because only one segment would be lit at any given time.  I'm really surprised that the numbers look steadily lit.  Even at 60 frames per second, it doesn't flicker at all.

Here it is displaying temperature and humidity.  I programmed it to read the sensors very 4 seconds but it displays the values alternately every second. 

Notes on the AMT1001 sensor:

There isn't a lot on the arduino community using this sensor so I had to dig long and hard to find the calculations to be done on the sketch.  The humidity part is straightforward but I find the temperature reading to be a couple of degrees inaccurate. It uses a thermistor and I had to use an external 10Kohm resistor for the temperature reading.  I compared the value to the LM35 reading and it's giving me a reading of at least 2 degrees lower. To triple check the values, I compared it to a room thermometer and the LM35 is very close.  So I concluded that it's really the AMT1001 that is off. I would probably just use it for the humidity reading and stick with LM35 for the temperature.

Here's a video of it with the thermometer for comparison: http://youtu.be/ShHf0ecPVl8