From LinuxGizmos Apr2021
Modular HMI touch-panel runs on Raspberry Pi CM4
Apr 15, 2021 — by Eric Brown — 8080 views
Seeed unveiled a $195, Raspberry Pi CM4-based “ReTerminal” HMI device with a 5-inch, 1280 x 720 touchscreen, a crypto chip, WiFi/BT, GbE, micro-HDMI, CSI, 2x USB, and 40-pin and PCIe expansion.
Seeed has announced a modular human-machine interface (HMI) device based on the Raspberry Pi Compute Module 4. The ReTerminal, which will go on pre-order later this month starting at $195, features a 5-inch touchscreen.
ReTerminal render images, front and back
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Despite the compact, 140 x 95 x 21mm footprint and mobile-like features such as an accelerometer, there is no mention of battery support. The device powers up on 5V@1A DC power via a USB Type-C port.
Like most Raspberry Pi CM4-based systems and carrier boards, the ReTerminal provides a 40-pin GPIO connector for Raspberry Pi HAT expansion. Like many, it exploits the module’s PCIe Gen2 x1 interface for expansion.
ReTerminal GUI display (left) and detail views
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There is no mention of M.2 or mini-PCIe, but only an external, rear-mounted “vertical high-speed expansion interface” with PCIe x1, USB 2.0 host, 26x GPIOs, and a PoE interface. Optional modules include mic array/speaker, LoRaWAN, 5G/4G, ZigBee, Sub-1GHz, PoE, and an Ethernet switch.
ReTerminal modules
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This description, along with the image above, the M4 mounting nuts, and a note that “all components and ports on the device are surface-mounted on two sides,” suggests that Seeed is launching a product line of custom expansion modules in plastic housing. These plug-ins will be supported by an “active community.”
The 40-pin connector supports standard Raspberry Pi HATs. However, the image above appears to show an enclosed I/O module plugging into the 40-pin, suggesting that Seeed may also supply a line of 40-pin HATs in custom modules. Seeed offers a lot of HATs and other Pi add-ons, including its recent, LoRaWAN-equipped WM1302 Raspberry Pi HAT.
The 5-inch, 1280 x 720-pixel IPS display with capacitive multi-touch features 293 PPI pixel density. By comparison, most 5-inch touchscreens are 800 x 480, says Seeed.
ReTerminal side views
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The ReTerminal runs Debian Linux on the Raspberry CM4, which offers the same 1.5GHz, quad-core Cortex-A72 Broadcom BCM2711 found on the RPi 4. It uses a model with 4GB LPDDR4 and 32GB eMMC. Therre was no mention of an 8GB option. The device provides 802.11-ac with Bluetooth 5.0 BLE, which is probably delivered via the CM4.
The system is equipped with a GbE port, 2x USB 2.0 host ports, and a single micro-HDMI port with 4K@60fps support. There is a 2-lane MIPI-CSI interface that supports an optional camera via a quarter-inch camera mount.
Also of note is the Microchip ATECC608A cryptographic chip for secure hardware-based storage for up to 16x keys. The secure element supports asymmetric sign, verify, secure boot, and key agreement functions.
The ReTerminal provides several extras including a digital light sensor, an accelerometer, and an RTC. You also get a power button, 3x user keys, and 4x LEDs. There also appears to be a speaker and some antenna mounts.
Further information
The ReTerminal will go on pre-order later this month for $195. No ship date was listed. You can sign up for notification and a $5 early bird coupon here. More information may be found in Seeed’s announcement and product/shopping page.
