I have been selling kits for the Octasonic 8 x HC-SR04 board for some time because I love seeing the projects people make with this board.
I sell the kits as a convenience to others but I have now decided to fully open source this project so that people can build this project without having to wait for me to have kits in stock.
Also, I am now only shipping to USA and Europe as packages going to other countries (such as India or China) consistently go missing and there’s nothing I can do to fix this. I’ve been refunding customers in full and losing money on those sales.
The bare PCBs can be purchased directly from OSH park (in packs of three) here.
The Eagle PCB design is available at https://github.com/andygrove/octasonic-board.
Documentation is available here.
Note that if you purchase the parts yourself you will need to burn the firmware onto the ATMEGA IC using an AVR programmer so this is not an ideal project for a beginner!