The design files for the Spark Core v0.2 have been published to Github:
This version can be considered a release candidate for Spark Core v1.0 (the version that will be delivered to Kickstarter backers); we expect to make minor tweaks but keep the overall design the same.
v0.2 includes some significant changes from v0.1, which was the version displayed in our Kickstarter campaign. These changes include:
- Added a uFL connector for an external antenna. This is a stuffing option, meaning that there is one PCB design, but two resulting versions of the Spark Core, depending on which components are “stuffed”: one with a chip antenna, and one with a uFL connector.
- Added an RTC crystal for accurate timekeeping.
- Improved RF design. The downside to this particular improvement is that it required making the Core slightly larger; the Core is now 0.1" longer than before (although the corners are kinked, so we really just gave the Core a ba-donka-donk).
- Improved power performance. We have made significant changes to the power regulator, which have some notable trade-offs. We’re using a larger power regulator that will be able to handle 500mA of current with proper heat dissipation. This regulator also has a very low dropout voltage (210mV) to improve performance with 3.7V batteries. The downside here is that this power regulator maxes out at 6V, so the Core is no longer spec’ed for 9V or 12V batteries. We were hoping to rate the Core for higher voltages, but there was unfortunately no way to do so within our size constraints; because of the current draw of the Wi-Fi module, an LDO would generate too much heat, and a switching regulator would create noise that could negatively affect the RF performance of the Wi-Fi module.
- An RGB LED for displaying the state of the Core’s internet connection. This makes debugging connectivity issues much easier.
- An LED connected in parallel to D7. This is much like the LED attached to pin 13 on the Arduino Uno; it means you can test out the Core with a simple blinking LED (or in this case, an internet-connected LED) without any external parts.
There were some other smaller tweaks and improvements, but that covers everything major. Enjoy!