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3M Microtouch 17″ Raspberry Pi Touch PC

A while back I posted about a 3M Touch Systems industrial monitor that I’d been given. I had previously paired it with a Raspberry Pi Model B+, but for general desktop use it was just a little on the slow side.

Since the release of the Raspberry Pi 2, with it’s 4-core ARM Cortex CPU, things are much improved, so I figured I’d post an update with the latest on the system.

The monitor I’ve used is a commercial one, used in such things as POS terminals, service kiosks, etc. It’s a fairly old unit, but it’s built like a tank.

3M Panel
3M Panel

It’s built around a Samsung LTM170EI-A01 System-On-Panel, these are unusual in that all the control electronics & backlighting are built into the panel itself, instead of requiring an external converter board to take VGA to the required LVDS that LCD panels use for their interface.

The touch section is a 3M Microtouch EXII series controller, with a surface capacitive touch overlay.

Touch Controller
Touch Controller

Above is the touch controller PCB, with it’s USB-Serial converter to interface with the Pi.

As there is much spare space inside the back of this monitor, I have mounted the Pi on a couple of spare screw posts, fitted USB ports where the original VGA & Serial connectors were in the casing, and added voltage regulation to provide the Pi with it’s required 5v.

Overview
Overview

Here’s the entire back of the panel, the Pi in the middle interfaces with a HDMI-VGA adaptor for the monitor, and the serial adaptor on the right for the touch. A small voltage regulator at the bottom of the unit is providing the 5v rail. There’s a switch at the bottom next to one of the USB ports to control power to the Pi itself. The panel won’t detect the resolution properly if they’re both powered on at the same time.

At 13.8v, the device pulls about 2A from the supply, which seems to be typical for a CCFL backlighted LCD.
Now the Raspberry Pi 2 has been released, it’s much more responsive for desktop applications, especially with a slight overclock.

Shameless Plug
Shameless Plug

A full disk image enabled for Desktop & 3M touch monitors is available below for others that have similar panels. This image only works for the Pi 2!

[download id=”5591″]

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Wearable Raspberry Pi – Some Adjustments

USB Hub
USB Hub

As the first USB hub I was using was certainly not stable – it would not enumerate between boots & to get it working again would require waiting around 12 hours before applying power, it has been replaced. This is a cheapie eBay USB hub, of the type shown below.

These hubs are fantastic for hobbyists, as the connections for power & data are broken out on the internal PCB into a very convenient row of pads, perfect for integration into many projects.

Breakout Hub
Breakout Hub

I now have two internal spare USB ports, for the inbuilt keyboard/mouse receiver & the GPS receiver I plan to integrate into the build.

These hubs are also made in 7-port versions, however I am not sure if these have the same kind of breakout board internally. As they have the same cable layout, I would assume so.

 

Connector Panel
Connector Panel

Here is a closeup of the back of the connectors, showing a couple of additions.

I have added a pair of 470µF capacitors across the power rails, to further smooth out the ripple in the switching power supply, as I was having noise issues on the display.

Also, there is a new reset button added between the main interface connectors, which will be wired into the pair of pads that the Raspberry Pi has to reset the CPU.
This can be used as a power switch in the event the Pi is powered down when not in use & also to reset the unit if it becomes unresponsive.

 

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Wearable Raspberry Pi Part 2.5 – Battery Pack PCM

Battery PCM
Battery PCM

The final part for the battery pack has finally arrived, the PCM boards. These modules protect the cells by cutting off the power at overcharge, undercharge & overcurrent. Each cell is connected individually on the right, 12v power appears on the left connections. These modules also ensure that all the cells in the pack are balanced.