ORBIT Mobile Node (version 1)

The mobile node is effectively a shrunk down version of the standard ORBIT node designed to facilitate mobile and off-site experiments. The current generation is based around the Intel Next Unit of Computing (NUC) platform.

Hardware

NUC + CM3 (rev. 4) + B205mini-i + charger and PS

NUC

Two versions:

1. Small: ​NUC6i5SYK with 6th generation i5-6160U processor, 32 GB RAM, 256 GB SSD
2. Large: ​NUC6i7KYK (aka "Skull Canyon") with 6th generation i7-6770HQ processor, 32 GB RAM, 256 GB SSD

SDR Front End

The SDR front-end ​Ettus Research USRP B205mini is a full-duplex transceiver platform with tuning range of 70 MHz to 6 GHz with 56 MGHz of instantaneous bandwidth connected over USB 3.0 to the host.

Standard 4x4 Case Extension

The "add-on" case extension to the small version contains the B205mini-i USRP and CM3. It is a 3D printable part (STL file​) compatible with the "short" and "tall" (2.5" drive capable) versions of the 4x4 inch NUC platform. Best 3D print results have been achieved using either ABS or HIPS filament. SMA connections are provided on the outside of the case for the USRP's TX/RX, RX2, and a 10MHz or PPS time reference.

Battery Operation

A second case extension enables car deployment and graceful shutdown using the ​OpenUPS2 power supply.

Assembly instructions

These instructions assume a build based on the "short" NUC6i5SYK. Use of a taller 2.5" drive capable NUC will necessitate longer standoffs or screws.

Parts:

• 1x 3D printed case extension
• 8x M2.5 x 0.45mm thread, 20mm long male-female standoff
• 4x M2.5 x 0.45mm thread, 12mm long round-head screw
• 3x 6" right-angle SMA male to regular SMA female cable
• 1x 6" SuperSpeed USB 3.0 A Male to Micro B Male Cable
• connectors & cabling to connect CM3 to NUC motherboard
  • 6" cable with "floppy power" connector and Molex 22-55-2041 to Samtec TCSD-05-01-N (power on sense and on/off/reset control)
  • 6" cable with TE Connectivity 179228-2 to TE Connectivity 440146-4 (for standby power)

Standby Power Cable Assembly:

TE Connectivity 440146-4	Description	TE Connectivity 179228-2
1	+5V Standby	1
2	Ground	2
3
4

Standby power is sourced from the NUC6i5SYK's "AUX_PWR" header next to the SSD. Other NUC's may have this header located elsewhere.

Power Sense and On/Off/Reset Control Cable Assembly:

Samtec TCSD-05-01-N	Description	"Floppy Power" Connector	Molex 22-55-2041
1
2
3
4
5	Ground		2, 4
6	Power Switch		1
7	Reset Switch		3
8	Ground	2
9	+5V (sense)	1
10

The NUC6i5SYK's front panel header is located on the "back side" of the board (opposite side of where the SSD is installed). Other NUC's may have this header located elsewhere.

Assembly:

1. Remove the NUC case bottom plate (it will not be used)
2. Remove motherboard (if necessary) and connect cables that will go to the CM3
3. Reinstall motherboard
4. Install standoffs (2x20mm per corner) in the four corners where the case bottom screws would go
5. Install SSD and RAM
6. Connect SMA cables to USRP before installing in case extension
7. Install USRP in case extension
8. Install the SMA cable between the USRP's 10MHz/PPS reference port and the rear of the case extension
9. Install CM3 in case extension
10. Install CM3 and connect the cables between it and the NUC
11. Install the SMA cables between the TX/RX, RX2 ports on the USRP and the case extension sides
12. Put the NUC and case extension together using the M2.5 screws
13. Attach the USB 3.0 cable between the NUC and USRP
14. Add rubber feet to the case extension bottom if desired

Assembled unit is hown in Figure 3.