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The SwitchBlade is a full size add on board for the Raspberry Pi. In our opinion It is the best and most useful prototyping board out on the market. It is based on the popular Humble PI board, but we've added terminal blocks, jumper wires and resistors to make this the perfect board for PrivateEyePi, giving you 12 switches, or alarm zones, leaving 5 spare GPIO pins for thermometers and radio frequency devices. 

Arranged with power down the middle and pads in groups of threes you'll find this much easier and faster to work with than other solutions.

The main specifications are:

  • GPIO header is broken out to twin row pads (convienent and fast access for more than single wire hookups)
  • Construction is very easy (suitable even for children with basic soldering skills)
  • Pick up points for the Pi 3.3v and 5v supply (flexible options for powering your project)
  • Centre power rails (perfect for powering IC's and it eliminates lots of wiring)
  • 2.54mm holes arranged in 3's (a really convenient layout)


  • Gold plated finish (Protection against oxidization means your device will outlast normal HASL boards)
  • Comes as a complete "self solder" kit of parts
  • Complete with supporting standoff

Build Instructions

Solder the 26 pin header to the revers side of the board as shown in figure 1.

Figure 1: Solder the 26 pin connector to the reverse side of the board.

The next step is to connect terminal blocks. Take some time to orient yourself with the workings of this board before you start. The board has GND and PWR running down the middle. On either side there are twin rows pads with three pads per row. The three pads are connected top to bottom in Figure 2. The lighter yellow block in Figure 2 shows 15 pairs of GPIO connector pads. The GPIO pins are mapped to these pads as shown in figure 5. Use a multi-meter to orient yourself around the board. Take special note of the 3V and 5V pads to the right of the header in Figure 2. You don't want to get these mixed up and never connect 5V to a GPIO pin.

The red and the black lines are jumper wires that you need to solder in place so that the center tracks are powered and grounded to the Raspberry Pi GPIO. Alternatively you could choose to connect external power. To keep things neat, connect all your longer jumper wires on the bottom side of the board, and the components on the upper side of the board. 

Connect the positive and negative jumper wires shown by the red and black lines in Figure 2. The negative is connected to Pin 25 of the 26 pin Header. This needs to be connected on the upper side of the board because the header block prevents your access to pin 25 on the under side. I usually solder a wire to the upper side of pin 25 and then thread the wire through one of the two 5V pads so that all my long jumper wires are neatly out of the way on the under side of the board.

Figure 2: Take note the layout of the board

Now you are ready to start connecting the terminal blocks. Figure 3 is the component diagram for the area marked by the bold yellow square in Figure 2.

Start by attaching the terminal blocks to the board. The terminal blocks clip together so you will need to assemble 6 on each side and push them in all together as shown in figure 3 and Figure 4. It takes a bit of force but the legs will push through.

Get one switch to work, and then move on the rest. As you become familiar with the pattern you will find the assembly goes quite quickly. Attach the resistors and jumper wires as shown in the Figure 3. The jumper wires go on the upper side of the board and the longer GPIO connector jumper wires on the under side. Some of the shorter connections you can make by bridging pads with solder on the underside. 

The GPIO connection shown in yellow in Figure 3 are connected on the under side of the board using jumper wire. 

Figure 3: Component diagram

Figure 4: The finished board connected to the Raspberry Pi. You may also notice a DS18B20 squeezed in to give a temperature reading from the board.

Figure 5: Mapping of GPIO pins to the pads on the SwitchBlade board. The SwitchBlade pin numbers are the 15 pairs of pads show by the light yellow block in Figure 2.

Figure 6: GPIO Header Pin numbers start top left with Pin 1, and pin 26 bottom right.