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Investigate the MUX circuit for 3 different LED signals (4) #15

Closed msaadq closed 7 years ago

msaadq commented 7 years ago

ACs:

  1. Investigate how to operate MUX with 3 sensors
  2. Investigate how to convert the LEDs to DCM equivalent sensor
ahsan commented 7 years ago

Solutions (ver 1)

1.How to MUX 3 sensors

One possibility of muxing 3 different sensors with the AFE4400 is to freeze the AFE4400 on a single sensor and feed the muxed led inputs to it. This mux will need to be controlled externally by a microcontroller. A jellybean mux like the 4052 has been shown to be suitable for this task by analysis and simulations done earlier. The design reference by TI shows that the AFE4400 has a different current setting for each LED (page 13 of the following link). This indicates that there might also be something in the software that handles the LEDs differently. This will also need to be taken care of in the mcu firmware.

http://www.ti.com/lit/ug/tidu475/tidu475.pdf

2.Convert discrete LEDs to DCM equivalent

Datasheet of the DCM03 reflective sensor shows that the device consists simply of two emitter and one sensor diodes. This arrangement can be replicated with discrete diodes too. http://www.disemu.com/upload/DCM03_datasheet.pdf