The first thing that people ask me when I show them my rock timing system is: "Can it work on my phone?" The answer is now YES! After lots of failures, there is now a method to have the system work as a standalone timer like the original version or also send data to a phone, tablet, computer via a website and also allow the website to control the system. Here are the additional features of LarryRockTimer2.0
Connect to an access point created directly on the backline unit. SSID=LarryRockTimer. Password=12345678
Direct a web browser to IP address: 192.168.4.1
System setup choose between 1 or 2 Hog Line Sensors. End a session and reset sensors without needing to restart.
Arm the System before delivering a stone. Just like the IR sensor which still can be used. Arm with phone or IR sensor.
Display interval times and speeds on a single page.
End Session and save data to a spreadsheet or simply end the session.
In addition to these features, the redesigned backline case is a simple two piece case that is MUCH EASIER to assemble even with the additional components needed to create the webpage interface.
If you want to make the cheapest possible system, ignore the ability to control it as a standalone system and only plan to use your phone for setup, arming, control and display. That eliminates the need for the OLED display and IR sensor. It will be a snap to build with fewer components and I don't even want to tell you how cheap it would be to put it together yourself.
Here are some screenshots from the webpage control system...
Plastic Part files for 3D printing
Assembly Instructions (need videos and detailed instructions)