SimulCharge USB for Phones: Car Music Player

5th Wednesday, 2014  |  Life at LAVA  |  no comments

The LAVA SimulCharge USB charging and USB host mode adapter now exists in a version for Samsung phones; specifically, the Samsung Note 2/3/4 and S2/S3/S4 (see compatibility list for all supported devices). This charging adapter makes it possible for you to attach USB peripherals to your phone in USB Host mode, and to continue to charge/power your phone at the same time.

Here’s a scenario: you might find (as I do) that it’s nice to have the music I’m currently interested in all on one memory stick. I can easily update music on my memory stick and plug it into whichever computer I am using.  With the SimulCharge USB my phone becomes a useful part of that system.

It might also be that your phone has limited memory and no ability to add a micro USB card.

I can now plug my phone’s audio output into the car stereo’s “Aux” input, and use the SimulCharge USB to host my memory stick while still charging my phone. That way I don’t listen to music in the car and arrive with a depleted phone battery.

There is more than one way to skin this cat. In fact, there are three ways of connecting your phone to your car stereo, and four ways to inject USB power into the SimulCharge USB. Here are the pieces:

• car radio with auxiliary input (3.5 mm phono plug) AND a 3.5mm to 3.5mm audio patch cable
• car radio with auxiliary input (3.5 mm phono plug) AND a 3.5mm to Bluetooth adapter
• car radio with built-in Bluetooth

• phone with OTG capability (for the SimulCharge USB, a phone compatible with the SimulCharge USB)

• LAVA SimulCharge USB for Phones (PL-002)

• a USB A to micro USB B cable (your Samsung phone charger’s cable) AND a cigarette lighter-to-USB adapter (Note: these adapters typically supply 1 Amp power at 5 volts, which is less power than would be provided by your phone’s charging adapter)
• your Samsung phone charger with cable AND a cigarette lighter-to-AC inverter
• your Samsung phone charger AND a built-in AC inverter in your car

The whole system. in its variants, is shown below.

car_layoutsSome notes on this diagram:
1) the radio options available depend on the make and model of radio; most these days have at least an AUX input, and many have built-in Bluetooth. Indeed, many also have USB inputs that will take input directly from a USB memory stick.
2) The car powering options depend on what particular power sources a car has. The traditional cigarette lighter is pretty much universal, although some cars have built-in inverters to provide AC power as well. The advantage of power options 3 and 4 is that they use the Samsung USB power adapter, which supplies 5.3V at 2.0A, whereas the typical cigarette lighter to USB adapter (Power Option 1) outputs 5V at 1A. This difference in power output can make a significant difference in charging. The image shows the power connectors of a 2012 Lincoln Town Car, a vehicle which is particularly well equipped with power outlets.

Finally, if you want to take another approach altogether, here’s a hacker’s take on car audio, using the Raspberry Pi SBC:

The Tablet Mini-Office

23rd Thursday, 2014  |  Life at LAVA  |  no comments

The LAVA SimulChage USB, in conjunction with one of the supported Samsung tablets, can make the backbone of a highly functional mini-office system.

Peripherals such as keyboards, mice, touch pads, printers, memory sticks, external hard drives, and Ethernet adapters can all be components. As far as printers go, there are basically two routes: using the Samsung software that comes installed in the tablets (“Samsung Mobile Print App”) and that is compatible with certain Samsung printers, or using a third-party application (such as PrinterShare™ Mobile Print ( to print to assorted makes and models of printers. You will need to verify compatibility in your particular case.

Here are a some sample setups:

Setup 1: Wired keyboard, mouse, external hard drive, and printer

This first setup is a fully wired office. The power requirements for such a system involve wall power for the printer, and for two USB power domains.

SimulCharge Mini-Office_03_700px

Setup 2: Wired keyboard, mouse, external hard drive, and wireless printer

This second setup is a hybrid design that uses the wireless printing supported natively in the tablet by the Samsung Mobile Print App. The software is supplied with the Samsung tablets, but the printer needs to be one of the Samsung-supported printer models.

SimulCharge Mini-Office_04_00px

Setup 3: Wired USB memory stick, and wireless keyboard/touch pad and wireless printer

This third setup has simplicity as its characteristic, as it uses no USB hub (powered or otherwise).

SimulCharge Mini-Office_01_700px

Setup 4: Wired Ethernet, network attached storage, networked printer, and locally connected keyboard and mouse

SimulCharge Mini-Office_02_700px

Many more combinations are possible. Using a wired Ethernet connection, for example, is easy and described in a blog post and video.

In general, the things to bear in mind are that the system needs to be designed with 1) supported components, 2) correct printer support, and 3) care to observe the USB OTG power budget. Discussion of USB power budgeting can be found in this LAVA white paper.

USB Power Budgeting White Paper

16th Thursday, 2014  |  Life at LAVA  |  no comments

Using a tablet to host an array of USB peripherals can greatly increase the power of these amazing devices, making many applications possible: kiosks, Point of Sale (PoS) systems, manufacturing control, and so forth. That’s all well and good, but the reality is somewhat more complicated. Unlike desktop computers,  and to a degree laptops, tablets are designed to run very lean, using minimal power.

When it comes time to hook USB peripherals to a tablet’s USB port operating in USB Host mode (also known as USB On-The-Go or OTG mode), problems can arise specifically related to the power that the tablet is able to supply to attached peripherals.

white paper fan

This white paper looks at powering peripherals on the USB bus, specifically in the context of the SimulCharge USB Host Mode and Charging adapter.

The white paper starts with a bit of electrical theory, describing the relationship between voltage, amperage, resistance, and power.

It then takes these variables to a discussion of USB power supplies, and sketches out how a system can go over budget  in its use of USB power through the number of USB peripherals attached to the USB bus power. That is followed with a discussion of cables and voltage drop that they can introduce. shedding light on an often-overlooked cause of power budgeting problems.

Finally, this white paper looks at powered USB hubs as a possible means of supplying additional USB power to a system, and what technical considerations must be kept in mind for such systems to work.

Download the white paper.

Unboxing the LAVA SimulCharge USB Tablet Host Adapter and Charging interface (TL-002)

16th Thursday, 2014  |  Life at LAVA  |  no comments

Here’s what you get in the box when you open the TL-002 SimulCharge USB package: the SimulCharge USB Adapter itself, an installation note, and a USB (male) to USB (male) cable to attach the adapter to a Samsung Galaxy Tab (see compatibility list for all supported devices). Note that the cable is a non-standard USB cable expressly for this purpose, so it is the one you need to use.

TL-002 unboxing blog page_700px

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