ECE 110/120 Honors Lab Section : TA Project LED Matrix

Project Description:

The ECE 110 Staff holds their offices hours in the room connected the ECE 110 Lab. Being in such clear view to ECE students and prospective ECE students, the staff would like a LED sign letting students in the atrium that office hours are in session. We will be utilizing numerous LED Matrices that will be daisy-chained together to create a vivid sign the entire department can enjoy and boast about. The initial design calls for 2 matrices that will scroll. We will then have a button implemented to change it from on to off then to switch between office hours in session to lab in session. We will then ask the machine shop to create a nice case for it all and then suction cup it to the glass in the classroom. The entire system will run off the rechargeable batteries from the ECE 110 lab. 

Original Block Diagram:

Updated Block Diagram:

Weekly Journals:

Week 1:

Today we created our block diagram. This process exposed some 'question marks' in our planned design, such as who is the user of our product, how will the sign be controlled, and how will it be powered. More specifically: will the sign be used by all TAs (Grad and Undergrad)? If not, will there be a schedule uploaded to the MCU to control what is displayed on the sign? Who will control this schedule and how will it be edited? Finally, will the sign be powered by a battery or an outlet. There is an outlet placed conveniently by the glass wall in the ECE 110 lab class room. After considering these questions we have decided to make a prototype using the basic design outlined in the updated block diagram seen above. All TAs will have control of this sign and it will simply change what is displayed by pushing a button connected to the MCU. Next week we will order the LED panels, MCU, Buttons, and a bread board as well as plan out font sizes to make sure we order the correct number of LED panels. The power supply will be made up of 4 rechargeable batteries found in the ECE 110 lab. The machine shop will be used to make a case for this device.

Week 2:

The progress this week was stalled due to waiting on parts to be shipped. We begun to discuss possible digital logic circuitry to control the system, in addition to planning out how each of the individual letters will be mapped with the LEDs. Sparkfun, the vendor we purchased the matrices off of, published a completed library of code for an Arduino Mega to power up a single matrix. However, a single matrix is not large enough for the sign so the libraries will need to be adapted to work with our setup in the upcoming weeks. Next week, if the parts come in we will begin to test the device with an Arduino Mega and begin to write code to display our desired messages.

Week 3:

This week we received the LED panels and began testing them. The data sheet stated that the panels will need up to 2 amps of current to work properly. We doubted this so we used a 1 amp power supply in the lab. Surprisingly the panel does draw 1.5 amps consistently so we ordered a 5V 2A power converter to power the panel. We will test the panel next week with this power supply.

Week 4:

We received the 5V, 2A power supply and we tested the panel with example code. One of the panels was damaged when 12V was accidentally applied to it. This can be fixed by replacing an OR gate that was broken. The other panel was tested, the example code seems to work partially with the panel. We are not sure if this is a code issue or a panel issue right now. The full library with text and shapes does not work right now, there is an issue with the code. These issues will be addressed next week.