Jul 26, 2012

Touch Panel Round II–Reach SLCD5+ Review

We are making our second touch panel based instrument, and due to response times and false triggerings of the GTT product we used last time we decided to try a touch panel from Reach Technology. I got my development  kit last week (5.7” High Resolution Development Kit (VGA), SLCD5+). The touch sensitivity on this panel is in my opinion far superior to the GTT. It is still a resistive touch panel, but for standard button touches it acts very much like a capacitive touchscreen. Lightly tapping a button with the pad of your finger works very well. Of course, being resistive, touching with your fingernail or stylus also works. 

Scrolling and sliding requires more pressure than I am used to when using a capacitive screen but my intended use won't include swiping or sliding controls. If yours does you'll need to train users to press harder. The firmware worked properly from day one, and the programming interface is a bit higher level than GTT's and easier to work with. There could still be even more high level commands. In fact I don't understand why manufacturers of touch screens don't supply some generic library C++ code that could be a starting point for most developers to use in their final applications. Surprisingly, while they have many unexpected features like a command to create a button with auto-centered text, they don't have a rounded rectangle command. That's a pretty glaring omission in my mind.

The biggest problem I have with the display is that it only supports bitmap artwork. This means there is no transparency support. This is a pretty big limitation in my mind. If I decide to change the background of my application I have to recreate all my artwork. Many of the lower level primitives like shapes and text do support drawing on a transparent background. Reach sorely needs to get on board with png support.

The display itself is gorgeous (but still limited to 16 bits). The development kit appears at first glance to be a bit pricey at $500 especially considering they couldn't be bothered to include even a single page of printed documentation. A single Getting Started page pointing out the hidden location of the SD card and the buried path on the CD of the primary manual would have been much appreciated.  That's a relatively minor nit (but easily fixed) and after that first day annoyance the development kit has been a pleasure to work with.

It's also worth mentioning that I wrote technical support inquiring about the ability to get a retro 7 segment LED type font, I asked specifically about several large sizes. GTT supplies a tool that allows  you to create versions of fonts you own that work on their touch panel. Reach includes no such tool. Reach's technical support not only responded within a day, but their response included the requested font in the requested sizes. That kind of technical support made both the $500 price and the lack of printed documentation a lot more palatable. 

We build limited production laboratory instrumentation so the cost of the display pales in comparison to the development costs. If you're in a similar situation I would recommend taking a look at what Reach offers.  They do offer volume discounts as well.

About Me

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Tod Gentille (@todgentille) is now a Curriculum Director for Pluralsight. He's been programming professionally since well before you were born and was a software consultant for most of his career. He's also a father, husband, drummer, and windsurfer. He wants to be a guitar player but he just hasn't got the chops for it.