Today we visit Sjaak’s workshop and talk about a USB 1.8″ TFT Backpack he’s been working on, as well as some history behind the popular ATX Breakout Board.
Sjaak describes the USB 1.8” TFT Backpack which features:
- 1.8” 160×128 pixel TFT, with 18bit color depth
- Micro SD card holder
- Small footprint designed to fit into a PC case 5 1/4 drive bay cover
- MiniUSB connector
- USB connection is solderable (for direct connection to a PC motherboard)
- Unused pins are broken out (digital I/O and analog input)
- 3V3 and GND broken out
- Buttons are broken out
- PIC18F26J50 uC
Current firmware supports the Matrix Orbital protocol. This allows it to emulate HD44780 character displays from a USB or serial interface. It works with popular LCD apps like LCDproc (Linux) and LCDsmartie (Windows).
Set a diode on fire? Sjaak used one of the extra ADC pins as simple analog data logger. A graph of the voltages measured is shown on the display. For a demo he hooked up a diode with resistor to measure the forward voltage of the diode. At room temperature the forward voltage is about 0.7 volts. Hold a lighter to the diode and the forward voltage drops quickly, as shown on the graph. Pop it in a mug of frosty beer and the forward voltage would increase.
This is Sjaak’s third revision of this board. He explains some of his earlier errors, and how he got around them.
We also got to take a look at the first version of the ATX Breakout Board, and some of the design changes made to the production version.
We’ll give away two free PCBs in the comments. Leave a comment on this post with an idea for this board and one could be yours tomorrow.