A few years ago LAVA was approached by a customer to develop a solution for utilizing an Android tablet as a low-cost controller along with several USB peripherals. Since then a number of LAVA products have been developed which rely on a feature found in certain Samsung tablets. While assisting a number of customers with their integration issues we’ve seen a reoccurring set of issues that keep coming up. Overall these issues can be grouped into one of two categories: Physical Issues; and Commercialization Issues.
Why does LAVA only support Samsung Tablets?
A few years ago LAVA was approached by a customer to develop a solution for utilizing an Android tablet as a low-cost controller, in conjunction with several USB peripherals. The project required that the tablet operates in USB Host mode with 24/7 functionality. This early product was the starting point for what would eventually become the LAVA STS-** family of devices.
There were several reasons for limiting the project only to Samsung tablets:
Continue reading “Using a Samsung Tablet for an enclosure – Part 2 of 3”
A few years back LAVA looked into the possibility of using an Android tablet as a low-cost control panel for a Thermostat control system with a series of network sensors. These discussions began after we were approached by a customer to develop a solution for a tablet-based loyalty system and as fate would have it, similar opportunities would present themselves a few months later.
Low-pressure molding is a relatively new process (to North Americans) that aims to encapsulate sensitive electronics using a polyamide material. The process was discovered in Germany in the 70’s as a result of the observed effectiveness of using hot melt glue (a polyamide) to strain relieve electrical connections on printed circuit boards (PCBs).
The original reason this project came through our doors was that SCI wanted to extend the life of the batteries in the tablets that are at the heart of their AED training kiosks. They asked Samsung for a solution and were referred to Lava and our battery modulation technology. It was then found that their product itself was quite flawed and I was tasked with redesigning it.
A typical USB power supply is rated at 5 volts nominal and a capacity of 1 to 2 amperes. The supply voltage will not be exactly 5 volts, but will vary depending on load (hence the amount of current being drawn). The voltage must never exceed 5.25 volts.
A typical USB Power supply is rated at 10 watts (i.e., 2 amperes at 5 volts DC).
When plugged directly into a generic USB supply, a tablet (or mobile phone) might appear to charge very slowly. This problem is common even when the supply has an adequate current rating. This is generally because the power supply is not a DCP power supply.
One of the main quirks when integrating a Samsung Tab 4 with any of our STS products (or Kiosk enclosures) has to do with booting up a Tab 4 from a power off state.
Samsung’s design of the Tab 4’s internal boot sequence is such that both charging and booting end up being disabled whenever a Tab 4 detects the appropriate single from an STS device (or Kiosk enclosure) to indicate SimulCharge Mode.
For our STS products this issue could be resolved by disconnecting the Tablet and either charging it for a bit or powering on the Tablet before reconnecting it. However for a Kiosk solution (which is often connected all the time) this really isn’t a feasible option. Since disabling of booting and charging is only an issue when the Tablet is in SimulCharge Mode we’ve managed to overcome this quirk by implemented a “Mode Select” button which provides the ability to toggle between SimulCharge and ChargeOnly Mode on the fly.
Most mobile devices (including tablets) currently use built-in Lithium-ion rechargeable batteries. These batteries have a high energy density, minimal memory effect, and low self-discharge.
When using replaceable Lithium-ion batteries, only use a battery charger designed for this type of battery. Charging a Lithium-ion battery with the wrong charger can damage the battery, result in a fire, or cause the battery to explode.
This article discusses issues for all STS-** products, the TL002, and the STS OEM board.