Adafruit Proto Doubler PiCowbell for Pico and Pico W

The Adafruit Proto Doubler PiCowBell is intended to be treated like a mini solder-less proto plate to simplify programming and sensor connectivity for your Raspberry Pi Pico board. Reset button? Yes! STEMMA QT / Qwiic connector for fast I2C? Indeed. Battery with recharging and on/off switch? Affirmative. Plug-and-play so no soldering necessary when used with a Pico H or Pico WH? Here you go!

The Doubler is like if we used a ‘Clone Tool’ on the Proto Under Plate PiCowbell – you get two slots side-by-side which means you can easily add accessories to your Pico or Pico W without soldering on any stacking headers.

Note: Pico and battery are NOT included

LiPoly Battery Charging Support

The Doubler also gives you Lipoly/LiIon support circuitry so you can take your Pico project on the go. Use any 3.7V/4.2V single-cell Lithium battery with a JST 2-PH connector in the correct polarity. The battery will automatically charge with the Pico plugged into the USB, and switch over seamlessly to the battery when USB power is removed.

By default, the charge rate is 500mA for use with 500mAh+ sized batteries. You can cut a jumper to reduce the charge rate to 250mA if using 250mAh to 500mAh battery. So you don’t have to unplug the battery often, a slide switch is connected to the Pico Enable pin, so you can disable the Pico’s 3.3V power supply completely – this is as close as we can get to ‘turning off’ the Pico.

Alkaline/NiMH Battery Pack Support

You can also cut a different jumper to disconnect the charger completely from the battery, which means you can use 3x AA or 3x AAA battery packs for alkaline or NiMH battery usage. Of course, you will need an external NiMH charger in that case.

Double Socket Headers

This board has double sockets already soldered on, you can plug in your Pico and ‘Bell boards directly, and get access to a prototyping area underneath as well as a second row of socket pins. The second row means you can connect wires just by poking them into the header, either directly to LEDs or buttons or to jumper to a breadboard. So you don’t have to look up or count pins, each socket is nicely labelled. There are also 4 mounting holes for easy attachment to an underplate.

The dual-socket headers we use are ‘hollow’ – that means you can connect through the back if desired. Specifically, you can use Pico Stacking Headers to plug through to some other device that is expecting Pico pins. Also, in theory, if you soldered pin headers on the ‘wrong side’ of a Pico, you could plug it up through the bottom.

We recommend picking up a set of little rubber feet to protect your desk if you’re not mounting this board to something else.

Features

• Two 2×20 slim socket headers – plug in your Pico and desired ‘Bell and have an extra row of sockets for each pin!
• JST PH connector for LiIon/LiPoly or Alkaline/NiMH battery usage – be sure to cut the ‘disable charge’ jumper to use Alkaline/NiMH batteries.
• LiPoly/LiIon charging circuitry for any 3.7V/4.2V nominal 1-cell battery. The default rate is 500mA, which can be set to 250mA by cutting the charge-rate jumper on the bottom. Two indicator LEDs let you know if the battery is charging (orange) or complete (green)
• Slide switch connected to the Pico Enable pin, which will disable the 3.3V power supply.
• Reset button that sticks out the end
• JST SH connector for I2C / Stemma QT / Qwiic connection. Or can use it for plain GPIO wiring if you don’t have any I2C devices to attach. Provides 3V, GND, IO4 (SDA), and IO5 (SCL)
  There is an extra set of 4 breakout holes next to the JST SH if you want more I2C connections or want to re-assign the I2C port.
• 3 hole-connected strips are in the center areas. You can cut the traces between the holes, but they’re intended to be treated like a mini-mini breadboard
• Nearly every pad on the Pico has a duplicate hole pad next to it for solder-jumpering
• The ground pads have white silkscreen rectangles to easily identify, plus one long ground strip near the reset button
• One long strip of connected holes for 3.3V power
• Gold-plated pads for easy soldering

We do not have I2C pullups on the board, but your Qwiic/QT breakout board or accessory likely already has them onboard. If using the Philhower Arduino core, the Wire peripheral is already set up to use IO4 and IO5. If using CircuitPython or MicroPython, you’ll need to let the code know to look at 4+5 for SDA+SCL pins.

Specifications

• Dimensions: 67.3mm x 52.0mm x 5.6mm

Resources

• Primary Guide