Ambient light and Proximity Sensor

Simple BLE device to monitor ambient light level and the proximity of the human body. Furthermore, device monitors motion and and logs the all collected data into non-volatile memory.

Requirements:

  • BLE interface for device configuration,
  • BLE real time data streaming,
  • Data logging into non-volatile serial flash,
  • ASL and proximity sensing,
  • Motion

Major components:

  • nRF51822 BLE SoC
  • VCNL4040M3OE
  • AT45DB641
  • BMA280

Number of PCB layers : 4

Realization time: 2 weeks

BOM price: 37 USD

Manual routing vs auto-router

Auto-routers can be a great tool if it is used correctly. Like any tool, it can be used to expedite certain tasks, and has limitations which need to be understood in order to leverage it effectively.

Young engineers entering the world of PCB design might be tempted to use the Auto-router tool expecting that this tool will do entire work for them. But soon they will see that this is not the case.

While we working on the custom development board we got an idea. For us, working on the development boards are always fun because most of the time these boards are symmetrical, and there is something quite mesmerizing about symmetry. (Figure 1).

We wanted to see how will the auto-router perform on this board. With the components already placed, for us humans, this would be a relatively easy task.

But for auto-router this was not an easy task. As you can see on Figure 2, the auto-router wasn’t able to finish the board. It gave us a couple of solution but non of them was finished. (Figure 3,4,5) show some of the solutions that we got from the auto-router.

Conclusion: When creating the auto-router, the creators where not able to replace the PCB engineers with the machine but they manged to give us a tool to increase our productivity.