Yup, you heard it right, version 1.2u of OpenSprinkler will debut at Maker Faire Bay Area on May 19 and 20. If you are going to Maker Faire, you are welcome to drop by and see our live demos. I started working on v1.2u shortly after releasing v1.1, and we were lucky to get the PCBs and components just in time for Maker Faire. The PCBs and components are shipped directly there, so it is not yet available for online purchase until May 23. But it is available for purchase at the Maker Faire and will be available online shortly after that.
So what’s new in this version? The main improvement is an on-board USB programmer. Specifically it’s a USBtiny ISP programmer built on a pre-programmed ATtiny45. USBtiny is one among many choices to directly program an AVR microcontroller without using a bootloader. The main advantages are that it is low cost (costs just a couple of dollars) and it enables the entire program space on ATmega328 (since no bootloader is needed). It is based on a post by Tequals0 and this version makes use of the internal clock and PLL on ATtiny45 to implement USBtiny with only three external resistors. Very elegant. With the on-board USB programmer, you don’t need any external programmer any more. Note that this version is named v1.2u, where u refers to the USB connectivity.
The second change is that some components have been replaced to adopt more common parts, including the switching regulator, the Ethernet jack, and the LCD. Also, there is now a rain sensor screw terminal, and a pinout for sensing power loss. The program will be updated to support these features soon. Another change is that the LCD pin assignment is slightly modified to free up analog pin 1, which is useful for talking to sensors. Finally, the extension board connector is also updated to use more common 2×3 pin header and cable. Note that this is still compatible with the previous version of extension board. If you have the previous version of extension board, it still works with v1.2u by switching a pin on the extension cable.
If you are interested, check the detailed release notes here and the release video below.