Anyone who has experienced an alarm clock in the morning will tell you that even a loud and harsh sound does not necessarily wake up from a deep sleep. Similarly, hearing a baby’s cry on the other side of the monitor may not always wake the parents in the middle of the night. So what is the solution? This tactile baby monitor designed by guy DuPont does look promising.
(Guy) pick up a fairly standard baby monitor from VTech, open it, and see how he connects the vibration motor to the original circuit. He initially thought that he had to do some signal processing magic to calculate the amplitude of the audio, but later he realized that the five light-emitting diodes in the front of the device were on to indicate the audio level, and had done hard work for him.
Therefore, he connected each led to the pin of the seeed studio Xiao nrf52840 microcontroller and wrote some code to poll their status hundreds of times per second. Dividing the total number of LEDs by the number of LEDs currently lit can get a good average value. He can use this average value to set the strength of the vibration motor built in the elastic arm band.
In addition, [guy] also uses the Bluetooth function of Xiao to provide basic configuration services – just connect the MCU with Bluetooth serial application on the computer or mobile phone, and then transmit a value between 0 and 10 to enhance the strength of the motor. There is also a ble feature, which can be read from the client device to determine the currently detected audio amplitude. This feature can be used to map the sleep of the baby over time. Alternatively, as shown at the end of the video, you can use it to play flappy bird.
This is an elegant modification that may bring hope to parents in need of extra help to help them monitor their own miniatures. This is not the first time we have seen hackers trying to improve the classic baby monitor, but it can be said to be the most approachable attempt we have seen so far.