I have a Grandma of 103 years, so sometimes her knees are weak and falls to the ground. As she is not really into smartphones, I thought of designing some hardware in order to help her to be safe at home... or at least be able to receive help when need to. From this idea, Safe Blue is born.

What it does

The Safe Blue is able to perform some safety related actions. It comes with a blank-out detector, as it is able to check when the person who is wearing it has suffered from blank-out and stands inconscious on the floor, by detecting movement of the person carrying the device. The device is also able to, via AT Bluetooth Commands, give advice of this situation to someone o something.

On the other side, the device can perform some orientation based on RSSI features, able to detect the approximate distance to some node.

Finally, it has a buzzer inside, and some RGB LED, to give acoustic and visual advertisement to the user who wears it.

How we built it

Internally, the device is composed by five parts; a PMU, some LEDs, one 9-axis IMU, the buzzer circuitry and, as last, the microcontroller with BLE capabilities. These parts are connected together in a small box designed with CAD software, which give all the parts an enclosure and protection.

All the device parts but the microcontroller are assembled by hand, as these can be seen in the pictures.

Challenges I ran into

The hardest point was deciding who was supposed to be the receiver of the alerts. At the beginning we thought of an Android APP, but due to the lack of time and teammates we had to abort this possibility.

Another huge problem was to communicate between the receiver and the transmitter on the network, and the results obtained for this part were acceptable at the end.

Accomplishments that I'm proud of

First of all, we are really proud to finish this project, as it became harder than we thought at the beginning. Our expectations were to do 6 devices, and we finally were able to do only 2. However it is a great satisfaction to see the work done and how it evolved during the two days.

What I learned

The hardest part for both of us was the BLE part, as we had not tried it before. The soldering part was quite hard too, as we had used components even smaller than 2mm x 2mm to make the PMU (Power Management Unit). This also caused some issues (broken components, cost increase, etc.).

What's next for Safe Blue

To continue this project, we would like to have a better electronic design, as this one is fully based on wire-wrap cables and toolings (can be seen in pictures). The results and also the application were good, but there are a lot of things to improve if we want to continue with this project.

Built With

  • arduino
  • bluetooth-ble
  • pmu
  • rgb-leds
  • wirewrap
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