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Mobile Power Pack Upgrade

New Regulators
New Regulators

The original LM2577 based regulators I designed into my mobile battery pack turned out to be insufficient for requirements, therefore they have been replaced with higher capacity regulators.

The 12v regulator (left) is a muRata UQQ-12/8-Q12P-C SEPIC converter, providing a max of 8A at 12.1v DC. The 12v rail is also now independently switchable to save power when not in use.

The 5v regulator (right) is a Texas Instruments PTN78020WAZ switching regulator, rated at 6A. The pair of resistors on the back of the regulator set the output voltage to 5.1v.

Also a new addition is a pair of banana sockets & a 2.1mm DC jack, wired into the 12v DC bus, for powering various accessories.

New Additions
New Additions

Below the USB sockets is now a built in eCig charger, to save on USB ports while charging these devices.

IWA National Festival 2013
IWA National Festival 2013

These changes were made after much field testing of the unit at Cassiobury Park, Watford, for the IWA National Waterways Festival.

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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 1.75

USB Hub
USB Hub

The hub for the external USB ports has been fitted here, with the two ports hardwired to the pads where once there were USB A sockets. This hub will also accommodate the wireless receiver for the mini keyboard & mouse, in the remaining port that will sit between the external USB ports.

USB Ports
USB Ports

In this gap between the ports is where the wireless receiver will sit for the keyboard & mouse, the pair of screws securing the external ports in the centre have been shortened to make more room.