Greetings everyone! Figured I’d update you on what’s going on with the Super Badge, the V2, NightMare Nights, and anything else I can think of by the end of this article.
First up, the fun stuff: Updates on the Super Badge! If you take a look at the last post, you’ll see some things about the Super Badge. Well, most of them are now wrong. I found a screen that, instead of taking up almost all of the pins of an ATMega328, operates under SPI. This means significantly fewer pins are used, meaning we don’t need to have the 328, or its associated hardware such as the MUX, at all. This trade actually reduces the total cost by a handful of cents. Even though it is SPI, it’ll use a few more pins. Three pins will be used by the Chip Select pins for the display, the touch controller, and the SD card. Additionally, the display needs another data pin and a pin for the backlight, bringing the total used pins to 5, plus the 3 for the SPI bus.
That’s not an insignificant amount of pins. The ATmega32u4 only has 17 digital pins, and we’re using almost half of them for the screen! It does have six additional analog pins but we’re still using a lot of pins. It was at this time that I came across the concept of port expanders. While I initially was looking for SPI port expanders to save pins, they were all fairly expensive. Then I found the PCF8574, an incredibly inexpensive I2C port expander. Each chip adds eight ports, and while they require the use of the I2C pins, this doesn’t prohibit the use of other I2C devices unless there’s an address conflict. With this in mind, I immediately added two of them to the board’s proto-design. Then I went even further and added a PCA9685. This is a 16-channel PWM chip, designed for use with LEDs but often used for controlling servomotors. It can also be used as a general-purpose PWM output as well. With these chips added, the Super Badge will have 43 pins available. Granted, 16 of them are PWM output only, but that’s still a lot of pins.
Now, for other things.
In a few months I’ll be heading out to Texas for Nightmare Nights where I’ll be selling the remaining V2 badges and will have the first Matrix Pendants there too. If things go well, I might even be able to have a Super Badge prototype there, too! Given my track record with prototypes, I don’t expect to have the Super Badge until closer to the end of the year. I fully expect the first few designs to have horrible disastrous flaws in them, but that’s why you prototype.
Now, if you noticed, I said the “Remaining V2 Badges” – As you may have presumed, that wasn’t a typo. I’m currently in the concept stage of an improved version of the V2 badge. Whether it warrants a V2.x label, a V2+ label, or even a V3 label remains to be seen, but it’ll be different. First thing I’ll be doing is figuring out the SD card reset issue. A capacitor’s been suggested to me and should do the trick, but the question is how large of a capacitor do I need? After that, I’ll be looking in to squeezing on a small Flash memory chip for storing settings through power cycling, and I’ll also be breaking out as many of the pins as I can manage. Most of them are used, so it won’t be many, but it’ll be all of them that are available. I’m having Alabaster adjust his case design to accommodate this new badge, so we don’t have to turn around and immediately redesign the case for the modified board.