Scrumtato is an ATtiny85-based gadget to keep overly passionate developers from excessively talking during daily stand-up meetings. The name stems from the combination of SCRUM and Hot Potato.

About Scrumtato

During our daily stand-up meetings (SCRUM), as we are a team full of talented and passionate developers, we just love to talk too much. This stretches our meeting and keeps us from getting the most out of our working hours. To solve this problem, here comes Scrumtato: A gadget to make daily stand-ups agile again!


How does it work

Operating the Scrumtato is simple!

  1. Press the button when you are ready to talk. You will hear 2 beeps.
  2. Start talking. You have to concisely explain what you did since the last meeting and what you are planning to do until the next.
  3. If you finish before the time runs out (in which case the Scrumtato will beep and vibrate), press the button again. You will hear 3 beeps.

More details

The user begins interacting with the Scrumtato by pressing the on-board button and starts talking about all the extraordinary things they got into since the last daily stand-up. This initiates a countdown timer that lasts as long as each team member is supposed to speak. To indicate that half of the remaining time has just been depleted, Scrumtato will beep once. For example, if the total available period for someone to speak is 1 minute, the user will hear beeps on approximately the 30th, 45th, 52nd, 56th, 58th and 59th seconds. As soon as the time is up, a characteristic beep sequence is played and Scrumato vibrates.

In other words, Scrumtato can be considered as a stress ball that… actually stresses you out! If the team member finishes talking in a timely manner, then they merely need to press the button again and a sound sequence that indicates the successful end of a turn is played.

From a technical perspective, since the users should not have to change the battery often, the microcontroller will go to sleep as much as possible. That is between “games” and between beeps or vibrations during the “games”. In the former case, the microcontroller is woken up by the button press and in the latter by a watchdog timer.

Other uses

Scrumtato was initially conceived as a toy for kids (or grown ups, no judging) and particularly, as a way to play Hot Potato. This use case is supported separately from the main one, however their integration into a common program should not be complicated as they share logic and states.

Specifically, the watchdog timer is triggered faster and the buzzer beeps when 5% of the remaining time is depleted, therefore more frequently compared to the stand-up scenario. Additionally, the on-board analog accelerometer is utilized to determine if a player does not pass the ball fast enough. In that case, a faster countdown is initiated and the ball must be passed in a couple of seconds otherwise it “explodes” in the hands of the one that was delaying the game. This increases the suspense and the pace of the game.

The Hot Potato use case is not supported since rev.3 as the accelerometer was removed. If you want to download that specific version then do git checkout -b hw_rev.2.


The use cases supported by Scrumtato can be found in the firmware directory.


From a physical perspective, Scrumtato is comprised of a PCB and a 3D-printed case to protect the electronics as well as make passing around easier and more fun.


The printed circuit board was designed with Eagle CAD and the latest rev. 3 boards were fabricated by PCBWay. Using the above service you can preview your board, as well as any changes you made, before ordering it and have it nicely packaged and delivered to your address in less than a week.

3D printed cases

Depending on the how you use Scrumtato, different case should be utilized. When used as a stand-up meeting gadget, it is probably not going to be thrown around. Therefore a case from common PLA plastic will work just fine. However, if kids come into the equation a flexible case is strongly suggested, since the gadget will be mishandled and dropped on the floor. After all, this is part of the fun. The flexible version was printed with a ZYYX+ printer, using their proFLEX filament. The PLA version was printed with a Micro M3D printer. The models were sliced with Simplify3D. If you need more information on the specific Simplify3D profiles used, tips on how to print (e.g. when to use support etc) or the source of the models, please contact me.



Scrumtato: Make daily stand-ups agile again