BotParty: Telepresence robots for $120 in parts

During the COVID-19 pandemic of 2020, most of us were confined to our homes and unable to socialize indoors with even many of our closest friends. What better time is there for telepresence robots? As most existing solutions on the market were too expensive, I set out to create the most inexpensive possible telepresence robot, built 10 of them, and held several social events with friends.

When many hobbyists hear "inexpensive", they instinctively reach for a $25 Raspberry Pi, but by the time you add the necessary HATs and boards to make a Pi-based robot actually functional (including battery management, motor controllers, etc.), you're often looking at several times that in price.

Instead, I used used Pixel 1 phones, which I was able to get from eBay for around $60-70 a pop. For that price you get a pretty decent processor, a high-DPI touchscreen, IMU, GPS, Bluetooth, Wi-Fi, battery, battery management. That's a pretty good deal for that price, and this was also my foray into repurposing old phones as robot compute that might otherwise become e-waste.

The robot uses a 3D printed chassis, a phone external battery pack, Pololu motors, and an ESP32 to drive the motors and for expansion for other sensors you'd like to add, if any. All the robot-side software is contained inside an HTML5 webapp that uses the Web BLE interface to connect to the ESP32 and drive the motors, and uses WebRTC on a video call with the operator.

The result is pretty neat. Although we're starting to get out of the pandemic, it's still a pretty neat way to socialize across timezones, and possibly even as a security robot if you want to check up on your home remotely while on vacation.

The robot is capable of wireless charging as well, so you need to just drive it up onto a Qi charging pad to recharge.

Build your own

Head over to my Github repo for plans and assembly instructions.