Mini-PC taps RPi Compute Module and supports RPi 2
Feb 21, 2015 — by Eric Brown 9,777 viewsKickstarter is hosting a wireless-savvy “OpenPi” mini-PC based on the RPi Compute Module. If you wait a bit, you can get one with the quad-core Pi 2 module.
For almost a year, the Raspberry Pi Compute Module has served the needs of professional embedded vendors looking to ship commercial devices based on the Raspberry Pi SBC. However, this computer-on-module (COM) version of the RPi Model B can be tricky for less experienced hardware developers. On Kickstarter, U.K.-based Wireless Things has successfully funded an “OpenPi” mini-PC based on the module designed primarily for software developers.


OpenPi case, and PCB showing Raspberry Pi Compute Module
(click images to enlarge)
The wireless-studded device is designed for prototyping, demos, and small product runs for home automation devices, media players, HTPC servers, and other IoT applications. The OpenPi is fully open source except for the case. Wireless Things was only recently called Ciseco. The company specializes in radio modules and RPI and Arduino add-ons.
Some potential applications for the OpenPi are said to include:
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- Internet of Things hub — ThingBox, Alljoyn
- Mini web server — LAMP stack
- HD media player — RasBMC, XBMC
- Playing games — PiPlay
- Bluetooth ibeacon
- Central heating controller
- Security systems — PrivateEyePi
Kickstarter packages
OpenPi Kickstarter orders are still open through Mar. 4. You can sign up for early bird packages of 29 U.K. Pounds ($44.65) for the PCB alone, which combines the module with a custom motherboard, or pay 55 Pounds ($84.70) for an early bird unit for the basic mini-PC model with Raspbian Linux pre-loaded. A complete model, which adds a power supply, an external antenna, an HDMI cable, and a wireless keyboard, mouse, and joystick, goes for an early bird price of 69 Pounds ($106.25). This will eventually sell at retail for 99 Pounds ($152.45).
All these devices are set to ship in April, but if you’re willing to wait until a September shipment, more or less, you can now order the OpenPi with an upcoming v2 version of the Raspberry Pi Compute Module for 99 Pounds. This is based on the new 900MHz, quad-core Cortex-A7 Raspberry Pi 2 Model B SBC with 1GB of RAM.
In the Pi 2’s announcement earlier this month, the Raspberry Pi Foundation said a Pi 2-based module would ship later this year, but made no mention of any future plans for the stripped down Model A. The fact that Wireless Things launched the same day as the Pi 2 — and that the company has identified the targeted ship date for the RPI 2 Compute Module — suggests some level of approval by the Pi Foundation..
Other OpenPi packages include a 335 Pound deal in which Wireless Things will offer you a custom branded logo design that you can load into an injection tool. Higher end packages ranging into the thousands of Pounds include collaborative development services.
Inside the OpenPi
The OpenPi combines the Raspberry Pi Compute Module with a larger custom board that integrates WiFi, Bluetooth Low Energy, and Wireless Things’s own “SRF” (Surface-mount RF) sub-GHz (868 to 915MHz) transceiver. The SRF radio is designed for communicating with long-range, low-power nodes, such as XRF or Arduino compatible RFu nodes, says the company. The radio is especially suited for Internet of Things applications such as connecting to low-power sensor devices.


OpenPi PCB rear view, and closeup of SRF wireless module
(click images to enlarge)
More information on the SRF radio is available on this Ciseco/Wireless Things SRF Wireless RF Radio surface mount module product page. The module, which sells for 12 Pounds, appears to be integrated on the back of OpenPi. It also powers a half-dozen other wireless products offered by the company, including wireless add-ons for the RPi and Arduino.


OpenPi PCB edge views, showing ports
(click images to enlarge)
The OpenPi adds a number of real-world ports to the RPI Compute Module, which lacks them. The mini-PC integrates dual internal USB 2.0 host ports, and provides dual external micro-USB ports, one for power and one for programming. An external HDMI port is available, as well.

OpenPi case from the side, showing the micro-USB power input (left) and HDMI port
(click image to enlarge)
In addition to the WiFi, Bluetooth LE, and SRF radios, the OpenPi provides an IR receiver, which like BLE, was a late addition. Other internal features include an XBee socket and 20 GPIO pins. The board-set is housed in a 104 x 79 x 33mm, “robust” injection-molded ABS casing, which can be customized for a price. Raspbian Linux is preloaded, and Wireless Things has already posted a full array of open-source design files.
Specifications listed for the OpenPi include:
- Processor/Memory — dependent on whether it’s the first- or second- gen Raspberry Pi Compute Module:
- First-gen. — 1x ARM11 @ 700MHz with 512MB RAM
- Second-gen. — 4x Cortex-A7 @ 900MHz with 1GB RAM
- Storage — 4GB eMMC
- Display — HDMI out (ext.) with audio and optional cable
- Wireless:
- 802.11a/b/g/n 2.4GHz (Ralink 5370)
- Bluetooth LE (late addition)
- IR receiver (late addition)
- SRF wireless 868 to 915MHz radio (Wireless Things SRF Module)
- Optional antenna
- Other I/O:
- 2x USB 2.0 internal ports
- 2x ext. micro-USB ports (1x power, 1x programming)
- XBee socket
- 20x GPIO (2x for power)
- 200-pin socket (dedicated to RPi Compute Module)
- Other features — RTC; temp. sensor; GPIO LED; optional wireless keyboard, mouse, and joystick
- Power — micro-USB port; optional power supply
- Weight — 90 g (case with PCB); 40 g (PCB)
- Dimensions — 104 x 79 x 33mm (case); 98 x 75 x 20mm (PCB)
- Operating system — Raspbian Linux preloaded with Raspiboot; Pi 2 version will also support Windows 10
Further information
The OpenPi is available on Kickstarter through Mar. 4 in packages starting at 29 U.K. Pounds ($44.65) for the PCB alone or 55 Pounds ($84.70) with case. More information may be found at the OpenPi Kickstarter page, as well as the new Wireless Things website. You can also find other RPi add-ons at the still open Ciseco website shop.
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