The White T Shirt Project
This January Designer label Prada was highly criticized for selling a plain white logo T-shirt for 270 Euros.
While T shirts from such labels are probably of higher quality both in fabric and construction, it is hard to explain the margin of up to 250 Euros when comparing prices with fast fashion brand like H&M or Zara.
Leading to the inevitable conclusion that what we are really paying for is a logo and overhead for brand identity.
This project takes a critical and ironic look at this issue by suggesting that customers only buy a digital logo. The logo of their choice will displayed on an LCD broach.The price varying, depending on the logo they chose.
The Board design for this project consists of (BAM):
1 1.8″ TFT bitmap display
1 Micro SD card reader
1 Micro SD card
1 ATMega 328 Microcontroller
1 ATMega socket bed
1 16 Crystal
2 22pf capacitors
1 3.3v regulator
1 500 mah lipo battery
1 lipo battery socket
I started by breadboarding using an Adafruit breakout board 1.8″ TFT display to check the connections, code and image display. I used an Adafruit basic example sketch to load my own bitmap of the Lacoste logo.
I planed on using an ATTiny 85 or 84 but soon realized I needed 10 pins meaning I would have to use an ATMega.
Trying to burn bootloader to the Mega using Minimal Circuit (Eliminating the External Clock)proved to be very difficult which was very frustrating considering it was an essential first step in realizing the project. It turns out that the new version of the Arduino IDE is known for having issues and I ended up downloading an older version and using two Arduino Unos to bootload. That worked but it meant I would have to recreate an Arduino on my board with an external Crystal and caps which I was not happy about because it meant the board would be bigger than what I had hoped.
After designing the schematic and the board which was mind bending since just about every power, ground and data line were intersecting each other on the way from the display, to the Mega and the card reader resulting in quit a few vias.
I decided to turn the display on to the other side of the board to allow for the flattest surface possible (remember those vias?)
One of the biggest challenges of this project was soldering. I have to give props to Jordan for walking me through creating a stencil for printing paste, which I ended up not using because everything was so small but mostly the displays’ leads are so close together I had to use a magnifying glass to make sure I wasn’t connecting them to each other. it was painful but it worked and I feel I have some really good soldering techniques gained from this project.
Looking at the image of this finished board gave me such satisfaction! This feeling quickly dissipated upon connecting the battery to discover it doesn’t work!! Cara, Nick, David and Jessy all have to be thanked for trying to help me figure out why?! I checked for continuity, re soldered two legs of the Mega bed which where a bit sketchy, and finally found the the problem is most likely coming from the regulator. The circuit is getting approximately 4.5v off the battery but coming out of the regulator is close to nothing. The Texas instruments data sheet suggests connecting 2 capacitors one of 0.33uf from input to ground and a 0.01 cap from VCC to ground. If I can find a 0.33 cap I can try this but I find it hard to believe this will solve the issue.
At this point I am not sure this project is going to work and I will be very sad if that happens but I will say, that regardless, I have learned a great deal. From different components and their functions, soldering techniques and paste control, paste printing and stencil making, trouble shooting ( I am positive that with more time I will get to the bottom of this mystery) and moved one step closer to feeling comfortable dabbling in tiny electronics.
In regards to fabricating the incasing for this project I found a 3D printed design for a case I thought would be a good start but don’t think I will be able to reach that point as I am knee deep in troubleshooting.
I thought I had found the problem and decided to mill a new board with a ground plain. re-soldering everything re-checking and guess what.. It still doesn’t work back to square one. 4.5v going in nothing coming out of the regulator…
It is 3AM and sadly I need to give up.. the evil lords of the fashion industry have won again!!
Notes to self and others:
- Breadboard as early as possible
- Work clean and precise
- Add led for power indication
- Add programable pins, microcontrolers don’t really like being remove
- leave a lot of time to debug
- know that you will follow all these steps and still it might not work and unless you work for Texas Instruments you won’t know why 🙁