Elad Orbach : diy control station

After carrying a laptop, XBee modules, USB cables and loose parts into the field many times, I decided that my laptop days as a ground station were numbered.

I wanted one durable case that could stay wired and ready instead of assembling and disassembling everything for every test.

I started with an old laptop that had a broken screen and another laptop LCD panel. To connect the replacement panel to the motherboard, I bought an LCD controller board that accepts VGA and drives the LVDS laptop screen.

Next I looked for a case large enough for the motherboard, main screen, a second small screen, panel meters and several three position switches. I found an affordable Pelican 1520. After installing the main screen, the remaining space was almost exactly right for a 5 inch HSD050IDW1 display with 800 by 480 resolution.

I tried Plexiglas, plywood and several other panel materials, but they were difficult to work with without the right machinery. PVC foam sheet was not very rigid, but it was easy to cut and drill, so I used it. A carbon weave vinyl sticker made the finished panel look much better.

Power system

I used a 12 V, 7 Ah sealed lead acid battery instead of a LiPo. It was cheaper, easier to charge and heavy enough to help balance the case.

I also wanted the station to run from AC power when it was available. A picoUPS 120 charges the battery and keeps the station running while the external supply is connected.

A step up converter produces 19 V for the laptop motherboard. A separate step down converter produces 5 V for the USB hub. Both converters are adjustable and have small panel meters.

The original 12 V AC supply was rated at 3.2 A. That was slightly below my calculated requirement, but it worked. If it failed, I planned to replace it with a higher current supply.

Cooling is provided by four Delta EFB0412HHA 40 mm, 12 V fans.

Connections and controls

An Asus WL 330gE access point allowed phones, tablets and another laptop to connect to the station. Other wireless connections included an XBee repeater, Bluetooth and 5.8 GHz video.

The second screen could switch between composite video and VGA through an HDMI to VGA converter.

I later added an HFX series Hall effect joystick. An Arduino and small servo converted the joystick movement for the original control mechanism.

Parts used

Old laptop motherboard and screen

Pelican 1520 case

VGA to LVDS LCD controller board

HSD050IDW1 5 inch, 800 by 480 display and VGA to AV controller

12 V to 19 V step up converter with voltmeter

12 V to 5 V step down converter with voltmeter

Temperature meter with two sensors, one inside and one outside the case

Two panel voltmeters and ammeters

picoUPS 120

Four three position, six pin switches

Four Delta EFB0412HHA fans

Carbon weave vinyl

12 V AC power supply

PVC foam sheet

Asus WL 330gE access point

Seven port USB hub

Braided cable sleeve and heat shrink

HFX Hall effect joystick

Arduino and small servo

eBay was not necessarily the cheapest source. For parts such as the regulators and USB hub, buying an assembled board was simply cheaper and faster for me than building each one from components. A USB hub could also be built around an FE1.1S chip or something similar.

The station ran for up to about two and a half hours from one 12 V, 7 Ah battery. It was still easy to modify because the panel could be removed and all of the parts remained accessible.

Ready for the field, without rebuilding the same pile of cables every time.

Build photos below.