A redesigned circuit shows a more mobile installation.  A 1/4 perma-proto circuit board is used like a breadboard.  A Pro Trinket 5 volt is soldered on.  The pulse sensor is connected to analog pin A0 and power.  The NeoPixels are connected to Digital Pin 5 through a 470 ohn resistor.  

Parts List:

The Pro Trinket 5V may be connected to the board via the male headers pins included with the Pro Trinket.  If you want a removable Pro Trinket, you can attach female header to the perma proto and male header to the Pro Trinket. The USB A side plugs into the battery pack, the Micro B side plugs into the Pro Trinket to provide power.  Tape or secure the USB to Pro Trinket end if you plan to flex the USB cable, as may happen in a wearable.  

Powering the Pro Trinket via the USB connector, you can take USB power out of the BUS pin for the rest of the circuit.  If you intend to power alot of NeoPixels and want to use a separate power for the 'Pixels, connect a separate 5 volt supply to the NeoPixels Pwr and Gnd pins AND connect the NeoPixel Gnd to the circuit ground (-) so the signal from the board (orange) has a ground path.  If you use another source of 5 volt power other than the USB cable, connect to the Perma Proto + and - lines AND put the red wire on the BAT pin on the Pro Trinket instead of the BUS line.

Connect the pulse sensor the data line (purple) to Pro Trinket pin A0 (analog pin zero).  Connect the NeoPixel data in connection (be sure it is "data in" or "Din") to the resistor.  Connect the other end of the resistor to the Pro Trinket digital pin 5.  Do not use digital pin 3 or digital pin 11 on the Pro Trinket as the sensor code disables the pulse width timer used for those pins along with the Tone function.

This guide was first published on Sep 29, 2015. It was last updated on Sep 29, 2015.

This page (A Wearable Circuit) was last updated on May 10, 2021.

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