Under $100 kit clusters five Raspberry Pi SBCs
Aug 10, 2020 — by Eric Brown 6,037 views
8086 Consultancy’s $99 “ClusterCTRL Stack” board-set enables clustering of up to 5x Raspberry Pi boards with support for a 12-24V power supply and dual 5V fans. You can also 3D print a case.
8086 Consultancy has launched a Raspberry Pi clustering kit on Tindie for $99. The ClusterCTRL Stack comprises a controller board and passive backplane board for clustering up to 5x Raspberry Pi SBCs (RPi B+/2/3/3+/4). There are also standoffs, screws, and clusterctrl software.


ClusterCTRL Stack assembled with 5x Raspberry Pi’s (left) and parts
(click images to enlarge)
The ClusterCTRL Stack’s controller board integrates a 12-24V DC input and 10-Amp, 5.1V DC-DC regulator for a bring-your-own 60W or higher power supply. A USB Type-A port supports 5V output for powering an optional, bring-your-own Ethernet switch. The controller board also supplies a micro-USB port, a 20-pin power header, a 6-pin monitoring header, and connectors for 2x independently controlled 5V fans.
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The passive backplane board connects to the controller board via 20+6 pin connectors and supplies 20-pin connectors for each Raspberry Pi. The backplane connects the BCM18 GPIO of each Raspberry Pi to the controller’s monitor header.
The ClusterCTRL Stack can be used on its own to automatically power up each Raspberry Pi after a one-second delay. You can modify /boot/config.txt on each Raspberry Pi using Raspberry PI OS (formerly called Raspbian) or other standard Pi distros to automatically turn on the fan at 75°C.
To get the most out of the product you need a standalone Raspberry Pi connected via the micro-USB port to manually install the supplied clusterctrl software. The software monitors the voltages supplied both to the SBCs and the 12-24V input and lets you control the power and fan for each Pi individually.


3D printed case with fans
(click images to enlarge)
8086 Consultancy recommends buying dual 70mm 5V fans to cool the cluster. STL files are available to 3D print one of two case designs, including one that houses the fans.
As noted by the CNXSoft post that alerted us to the product, 8086 Consultancy also designed the 4-board, $49 RPi Cluster HAT v2.3 sold by Pimoroni, which supports the Raspberry Pi Zero. Cluster products that support full-sized Raspberry Pi SBCs include IPTerra’s recent, 4-board CloverPi, as well as BitScope’s Blade boards. Turing Pi’s $128, 7-board Turing Pi Clusterboard and MiniNodes’ $259 5 Node Raspberry Pi 3 CoM Carrier Board support the Raspberry Pi Compute Module.
Further information
The ClusterCTRL Stack is available for $99 at Tindie plus $12.80 for shipment to the US. More information may be found on the ClusterCTRL Stack website.
What’s the purpose of Stacking ?
Should’ve done so with an amlogic S905x3 or the latest 922