The Raspberry Pi Compute Module 4 gave us the power of the Raspberry Pi 4 in a smaller package but it came with a cost, the Compute Module 4 needed carrier boards for GPIO access, USB, Ethernet etc. Tofu, a carrier board from oratek is designed for industrial applications and it comes with features not found on the official Compute Module 4 IO board, including an M.2 socket for use with NVME SSDs and 4G network cards.
Carrier boards are a necessity for the Raspberry Pi Compute Module 4 as they are designed for use in custom designed boards which breakout the features required for a project. For example the Otto camera which used the original Raspberry Pi Compute Module and official camera.
Tofu is a custom carrier board for industrial applications and measuring just 3.5 x 3.5 inches (90 x 90mm) Tofu crams a lot of functionality into a compact board. Tofu cleverly uses both sides of the board to provide an M.2 2242 B key slot compatible with NVME drives and 4G network cards so no need for PCIe boards. Additionally there is also a Micro SIM slot for use with 4G network cards.
There are two methods of directly powering Tofu and attached M.2 devices, a 2.1mm barrel jack and a terminal block, both of which can work with voltages between 7.5 and 28V. Tofu provides circuit protections for ESD and reverse current, handy for those moments when you mix up the polarity of your power input. The onboard Gigabit Ethernet port also supports Power over Ethernet (PoE). Power to the Compute Module 4 can also be supplied via the USB C interface, but this does not provide for the M.2 slot.
Tofu is designed solely for the Raspberry Pi Compute Module 4 and it is compatible with all variants of the board. We see the familiar 40 pin GPIO along with M3 mounting holes to securely hold your HAT board. We see three USB ports, which will most likely use USB 2.0 as USB 3.0 is not part of the spec for Compute Module 4. The official Raspberry Pi Camera and Display can be used with Tofu but it will require the use of cable adaptors, purchase separately. A full size HDMI port and a micro SD card slot round off the features found on Tofu.
Tofu is available for pre-order for Sfr. 99.00, around $109 including taxes.