I started with designing the board. The sensor I am using is an ultra sonic sensor. So the the board was relatively very simple but i had to use pad from another part as I could seem to find pads for the ultra sonic sensor so i went with some othe parts that had samilar pad that i could use for pins on ultrasonic sensor. The processor used is AT tiny 45. Apart from communications port(i.e FDTI and 6 header pin) the other component I used are 10K pull up resistor and 1 uF capacitor for smoothing noise in the circuit. I forgot to take a screen shot for this... snap!!!

Today, I have decided to redesign my board completely to use it later for my final project. So, I added 4 Switches and a header that has TX and RX these pins are for my communication and interface week. I have also added pin for ultra sonic sensor. I have fully utilized all the pin in the processor. I do have some doubts about how they all will interact but I guess we will find out. I just completed the schematic right now, I need to reconfirm if all my connections are right before making the board design so after checking with my lecture, I will move along with the design of the board. I am starting to understand connections and functions of the components better now, so I am happy of my progress.

I had some doubts about how the switch will respond with the VCC and GND placed from different sides of the resistor.

I learned that if the vcc is from the side of the resistor the signal at the junction between the resistor and the switch when the switch is turned on the signal at the junction is zero. But if the VCC is from the other side of the switch without the resistor the signal is 1/on. They are both the same idea which can be programed in ways that suits our need.

I found out that I can directly connect my switch between the input pin and ground after referring to the switch board by MIT. So that was also edited from the schematic.

Today after discussing with friends , I noticed that I forgot to add output pins for my stepper motor and all my pins are used so I decided to cancel the ultrasonic board from it.

Now all my designs are done, I have even designed the board. I did auto route but it was very complex and it required two sides so to make things simple , I went with manually making all the traces and Some connections I couldn't make on the route I am planning to use wire later. Now its time for milling. My first designs saw some issues with clearance for the bits between some traces in the mod display so I had to redesign the board. After three times redesigning and getting some mistakes on the board finally this design was working now.

Now after my design was a go , its time for milling. My label on the design was too small so it was milled off but the traces are nice so it fine!

After this it was cutting out, I have drew a line between the switch connections and the all the other components. This is because I want to use the switch as the user interface and having the header and other components will disturb the aesthetic so I have solder few long jumper wire to create the separation.

Now its time to solder. In the process of soldering I have found that I have missed some of the connections, instead to milling again, I did some surgery into it. I added thin wire to complete connections where I missed out in the designs. Now lets see how programs run in it.

Now I have checked all my connections using a multi meter and so far, it's good.

Programming the Board

Now moment of truth, I need to program to see if my connections were alright. My instructor helped me and I am using arduino as programmer for my board. The first step is to program the arduino as ISP programmer so I started by uploading the code for ‘arduino as ISP ’ from the example code in the arduino IDE. After uplaoding the example code, I connected the IPS header with the following pins on arduino board.
GND on board to GND on arduino
VCC on board to 5V on arduino
RST on board to 10 on arduino
MOSI on board to 11 on arduino
MISO on board to 12 on arduino
SCK on board to 13on arduino


During the process of programming I accidentally damaged one of the six header pin so I need to mill again. I also made the label on the board larger this time so hopefully we can get that also milled properly this time. I tried burning the boot loader but it failed every try so I checked out my board and noticed that my communication with the board was set to pins that were not set to it so after referring to data sheet I found that MISO , MOSI or RST pins need to be get at its particular pin specified on the data sheet. So I redesigned the board with new connections as required. After that I milled the board again. The finish was very clear.

Now its time to solder, again. Below is the main board

Below is the button interface

After getting all components soldered on I started again with programming it.I didn't face any issues burning the boot-loader. Even the program loaded well but there were some issues. My plan is to start with zero when the switch is off and after turning the switch on the voltage directly increases to 5v but I am getting noise which is making my LED lit up a little already before turning my switch on. After turning my switch on the LED gets brighter. And when hand motions distrubed the LED


The video below show the reading on oscilloscope. Square waves are generated between 5v and 0, when actually a straight line at 0v is expected. Which lead to different and strange behavior from the LED that blinks without the button being pressed or when my hands hovered over the circuit.


After referring to some tutorials and suggestions from my instructors , I was recommended to add pull down resistor of 10k ohms at one end of button , ground it , make a junction here and take it to a pin on the board and the other pin of the button is supplied with 5v.


So, I prototyped on Arduino and breadboard. Taking the reading from the oscilloscope shows a straight line at 0v when the switch is open and when it is turned on, the wave directly increases to 5v which is according to what I need. And the LED was blinking as I pressed the switch as showed in the video 'here'

Even simple switch was pressing hard on me because I didn't understand well and also the people in my circle had difficulties figuring out which made it more interesting.


Analog signal exist in wave forms where as digital signal is either high or low signal or 0 or 1. Due to the binary nature of digital signal, it is ideal for storage of data without being affected by radiations and noise. Though it's the digital age, analog still plays an important part on our life like the music we play from our phone or the voice that is recorded in a studio. The conclusion is both makes the modern world work well.

Below are few

All the design files are