As discussed in the June, 2011 Wired article, Harnessing the Power of Feedback Loops, it is important to deliver actionable data quickly and preferably “in a context that makes it emotionally relevant.” Most of what we do at RJMetrics revolves around data visualization and reports, but there are other ways to deliver information.

Enter the Gonginator

For thousands of years gongs and bells have been used to signal important events, and what news is more important to a startup than the arrival of a new paying customer? During our Spring Hackathon, Xiao, Rohan and I built an automatic gong ringer. Gonginator 1.0 was built using an Arduino microcontroller, node.js, the Noduino project, and an electric windshield wiper motor. A POST request to the node.js server signaled the Arudino to turn on the windshield wiper motor for 5000ms and then turn off.

Eight hours into the project we realized we underestimated the gong ringing mechanism itself. We thought simply banging a rod or a stick into the gong would work, but the spinning motor’s contact point needs to push through the gong to make a full revolution. This deadens the sound and requires a significant amount of force. We improvised by crafting a disc from a pizza box to swing the hammer in a circle, which solved the force issue, but it proved unreliable. The hammer occasionally jammed the disc.


During our Summer hackathon we revisited the Gonginator project and, at Shaun’s suggestion, invested in a WeMo device allowing us to signal the gonginator motor directly. This eliminated the need for the arduino and the node.js server, which had to be hooked up all the time. For some reason, the motor also spun significantly faster without Arduino providing the control system.

We also tried a simpler gonging method with a hooked stick instead of a disc. This made the gonginator more reliable, but didn’t completely eliminate jams.


We configured the WeMo to be signaled via email using and added some code in RJMetrics to send an email alert to whenever we got a new customer, which initiated the WeMo and the Gonginator.

Phase three was the followup to the Summer hackathon. We came up with a solution that gave us the reliability of just smacking something into the gong, while allowing the arm to continue freely once the hit was made. We settled on a stick attached to a rubber ball on a string. I acquired a few from their natural habitat (under furniture at my house) and drilled holes through them for the string. This is how the final product turned out.