My primary reason for wanting a PiTouch was to assess its use as a touchscreen for Pi Presents. Pi Presents is multimedia presentation toolkit and has a ‘hyperlinkshow’ in which the user can navigate between tracks using touch buttons. Until now I have been unable to find a reasonably priced touchscreen that is known to work with the Raspberry Pi. The PiTouch is reasonably priced, works with the RPi, and for me has potential other uses.
Having seen PiTouch on Indiegogo I emailed Dan to ask if the unit would be available even though the Indiegogo campaign had not reached its target. He replied that several Beta Test models had been made and the project would soon appear on Kickstarter together with PiTablet (it’s there now ending 7 January 2015). He offered to sell me a beta test pre-Kickstarter unit in exchange for a review which duly arrived well packed from Hong Kong just after Xmas.
Unpacking the unit I was pleasantly surprised with its build quality. It is shiny black and has a very solid feel, the buttons are positive and the leg sturdy. The front on the unit is, just like an IPad, all glass with only the tiniest of flush bevel. This adds to the stylish look and is ideal as a touchscreen. There are some good pictures of the PiTouch in another review here. The supplied leg unclips easily and you can plug in a second leg that has a a Pi case attached to it. The Pi fitted well in the case but disappointingly the case lid did not stay on. Later inspection of the lid indicated that the probable cause was that two small clips had broken off. A secure lid is important because without it the bent cables push the Pi out of the case. In my case a length of sellotape fixed the problem.
I had a spare Rev 1 256MB B model Pi which I used to try out the PiTouch. There are a number of cables supplied and many sockets on the unit and I was initially a bit concerned that I would connect everything incorrectly and possibly blow up the Pi by both back powering and forward powering it at the same time. No worries, the set of cables would only fit one way, Dan assures me that powering both ways will not damage anything, and there would be paper instructions with the Kickstarter version.
Having connected everything and switched on, funny things started happening. It turns out there is a known problem with back powering early version Rev.1 Raspberry Pi B models which will be fixed in the Kickstarter version (see here). Using a later B model or not back powering from the PiTouch solved the problem for me.
I was very impressed with the quality of the display. Text is crisp with good contrast. Comparing it with an IPad I could see little difference. I fully expected that, with the small size of the screen, I would not be able to use it for software development. But I think I can, so together with a small keyboard, mouse, wifi dongle, and piece of board, I now have a ‘laptop’ Pi.
Next to try the sound. Initially I could not get this to work but after editing config.txt to make HDMI_DRIVE=2 it burst into life. I was a little underwhelmed with the quality of the sound, having been amazed by my daughters IPhone that seemed to fill our living room with music from tiny speakers. The internal speakers produce a somewhat thin sound and there is no bass boost. Fortunately there is a stereo headphone socket which allows the PiTouch’s sound to be piped to an external amplifier.
The remote control is used to control the display as would your TV remote. It has on/off, volume and, most importantly for me, easy to use menu control. No more tearing my hair out trying to remember which of the four buttons that I cannot see controls what on the menu. One of the Kickstarter comments says that the monitor is likely to be CEC enabled in the future by updating the firmware.
I have other uses for PiTouch. I have a wildlife camera setup at a local nature reserve so the composite input would be very useful for testing these. Also a friend pointed out that many digital SLR’s have HDMI connectors so the PiTouch could be used as a viewfinder or as an in field playback device. Dan tells me that the PiTouch is reverse polarity protected and consumes about 0.6 Amps at 12 volts so a reasonably sized lead acid or NiMh battery would be adequate for field use. Also, since the input voltage range is 5 to 16 volts, a USB Power Pack (commonly used for recharging cell phones) will also allow for portable use.
USE WITH PI PRESENTS
Without a touchscreen I have been testing the touch screen capability of Pi Presents with a mouse. All that is required of the PiTouch was mouse click emulation. This mouse click emulation worked out of the box with no need for special drivers or kernels. It even worked without the calibration file that Dan provided. If you want multi-touch capability see the review here.
There are other considerations if a touchscreen is to be used in a public place. It needs to be well secured and the controls and leads need to be inaccessible to little fingers. PiTouch is provided with two holes for a VESA wall mount which normally has four holes. I think this will be insufficient and anyway the controls and leads will still be accessible. The sides of the Pi Touch are beveled so there is no way to mount it inset into a panel. However it would be possible to mount the PiTouch behind a thin panel. With this mounting the loudspeakers will be obscured and it will be necessary to use an external amplifier and speakers. Finally is 10 inches large enough for a touchscreen for public use. I have little experience of this; the text is perfectly readable and touch functions work well so why not; what do you think?