Tecla Shield for iPhone and iPad – Adding greater switch access to iOS

The Tecla Shield switch interface for the iPhone and iPad is one of a new generation of switch interfaces that promise greater access to the iOS functions for people who use a single switch.

The Tecla Shield has a couple of control options – one option is for one or two single switches.  The other option is control through the ECU component of a motorised wheelchair controller. This blog entry won’t address the wheelchair control option – instead I will focus completely on switch access.

The Tecla for iOS was extremely easy to setup. The very first thing I needed to do was to give it a power source. I just plugged it into the USB port on my Macbook using the provided cable – but I also ordered an external battery so that in the future I can be more mobile with the switch interface.

Almost as soon as I plugged the Tecla Shield into my Macbook, a red light started to flash within the Tecla Shield box. Once the red light had started flashing on the Tecla Shield it was ready to be paired with my iPad. To do this, I just needed to make sure that Bluetooth was turned on on my iPad and then select the TShield from the list of Bluetooth devices. Once I selected “Connect” my iPad and the Tecla Shield started talking and the internal light changed to a solid green. The manual for the Tecla Shield covers this basic setup very well.

The next stage of the setup was to go into the Accessibility options on the iPad and turn on VoiceOver.  The Tecla Shield uses VoiceOver as a way into the iOS.  This means that for the switch interface to control an App, the App must be VoiceOver compatible. The Tecla Shield works with most of the pre-installed Apps made by Apple that come on your iPhone and iPad – as well as some of the others that are VoiceOver compatible.  There isn’t any software to install – so once the switch interface is connected to your iPad/iPhone via Bluetooth and VoiceOver is turned on you are ready to go.

The Tecla Shield can be controlled by just one switch. The video below shows me scanning the home page of the iPad and then launching the YouTube app using a single switch. I then search for a video, play it and stop it using the switch.

(edited to add: video is no longer available)

As you can see in the video, single switch scanning with the Tecla Shield doesn’t follow some of the standard scanning protocols that we are accustomed to. A single switch press starts scanning through all the VoiceOver hotspots. A second press, reverses the scan instead of selecting an item.  To select an item, the user needs to hold the switch down for a longer press.  In fact, holding the switch down for different lengths of time changes the function of the switch – the first length, Hold 1, selects the item currently being scanned. Further controls can be accessed by holding the switch down for increasing intervals.

The table below shows the range of functions that can be accessed by holding switch 1 down for increasing periods of time. (edited to add: table is no longer available)

In the video you will see that I select the cancel function in the window that pops up asking me to select a WiFi network – I do this by pressing the switch until Hold 3 is activated.  If I had continued to hold the switch, then the Home button would have been activated.

It’s also important to note that because VoiceOver is being used to provide the scanning, the scan also isn’t like our more familiar scanning patterns from traditional assistive technology. Once the end of the scanning array is reached, it doesn’t wrap back around to the top. Instead, the user needs to press the switch to reverse scan back to any items they want. In addition, VoiceOver “scans” items that are important for audio description but are not important for someone controlling the iPad with a switch e.g. the title of a page.

Control of the Tecla Shield isn’t limited to one switch – there is an option for two switch scanning. This is also unlike the two switch scanning available in more traditional assistive technology. In two switch scanning with the Tecla Shield, Switch 1 starts the scan happening and Switch 2 selects the item when the scan gets there. Switch 1 does not need to be pressed repeatedly to get the scan to move along.

The other option of the Tecla Shield worth mentioning, is the option for changing the scanning speed. This is provided using the Programmer Accessory.

Pressing the “+” and “-” buttons on the Programmer accessory increases and decreases the scanning speed and hold times. It is nice to have this control – but the setup of the Programmer Accessory means that many users will be unable to do this independently – as the accessory needs to be plugged into the serial port on the Tecla Shield before use – and the + and – buttons are very small targets. In addition, as the scan speed decreases the hold time also increases.  This could be a big disadvantage for a user who needs a slow scanning speed but then can’t sustain a very long switch hold to perform some of the other functions needed to control VoiceOver compatible apps.  And just to give you an idea, according to the manual the scanning speed can be configured with a range of scanning delays of 0.3 to 5 seconds. Corresponding hold times range from 0.7 to 2.5 seconds.

And finally, it is important to note that although the Tecla Access uses VoiceOver to control the iPad, this does not necessarily mean that the switch interface gives the user access to all VoiceOver compatible apps or to all features within a VoiceOver compatible app. A good example of this is iBooks. The Tecla Shield is able to launch iBooks, and easily selects and opens a book.  However, once within an eBook, two and three finger gestures may be required to turn pages with VoiceOver active and the Tecla Shield is unable to emulate these.  This meant that I was only able to change pages in books within iBooks that had an inbuilt menu driven system for selecting pages – and of the 10 books I tried only 2 books had this option. This is something that needs to be standardised to offer more complete access within iBooks.  (Access to VoiceOver gestures may be more possible through the ECU setup on a wheelchair as the Tecla Shield does offer some gesture control through that interface.)

Overall, I think the Tecla Shield is a big step forward in greater switch access to iOS. It is easy to setup – and although some practice is definitely required to get accustomed to the interface, this didn’t take me a very long time to get acquainted with it.  Some familiarity with VoiceOver is definitely a help in getting going with the Tecla Shield in iOS, although it isn’t absolutely necessary as long as you are prepared to learn with trial and error.  Using the Tecla Shield I was able to type into the Notes app, send an email and search for a website and a range of other functions. I was able to do a whole lot more with a single switch than I have been able to before – and this is exciting for a number of users who want to use an iPad but haven’t had an access method until now –  even if that access is limited to VoiceOver compatible apps and there are some other limitations still to be worked through.  A BIG step forward in switch access to the iPad and iPhone.

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Comments (20)

  1. Jeanne Tuthill


    Disappointed that the two switch scanning still requires the user to time the activation of the “chooser” switch. I work with many kids who would have issues with timing their movements to activate the switch at the right time. I know at you can slow down the scanning but this would slow down the whole process unnecessarily and it still requires activation within a window of opportunity. :-(. Definitely a step forward for iOS accessibility but more work needs to be done to meet all needs!

    • Reply

      Agreed Jeanne – it’s a big step in the right direction but there are lots more steps to come.

    • Reply

      Hola Jeanne, Please note that step scanning (that is the kind of scanning that does not require the user to time the activation of the “chooser” switch) is built-into the ECU Port of the Shield and can be used with standard switches by plugging the ECU to multiple switch adapter available from Komodo OpenLab. However, since VoiceOver does not wrap-around scanning options as Jane explained, 3 switches are needed for full access: One to scan forward, one to scan in reverse, and the “chooser” switch. This means you can fully control the hold timings without worrying about the auto-scan timing since you would not be using it. This is the most comprehensive solution we found while pushing the boundaries of what VoiceOver allows as far as technically possible.

      Very comprehensive and insightful review about our Shield Jane, thank you for taking the time to post it!

      • Jeanne Tuthill


        Thank you for the clarification! Good to know there is a step scan option! I am very excited about switch accessibility on the iPad and was so glad to see Jane’s review. I am in the midst of prepping to teach a course at Simmons College this summer and will be sure to include this in my accessibility section!

    • Reply

      Thanks Timonthy – I’m really looking forward to seeing the Switch2Scan when it comes out (currently scheduled for July I believe). It will be nice for people to have some options and to see which one best suits their needs.

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  11. Angie


    Have you been to use the Tecla Shield (or any other set up) so that an aug com user can use his/her wheelchair joystick to communicate using an app such as Proloquo2Go?

    • Reply

      HI Angie,

      I haven’t set this up – but the people at Komodo tell me it is possible. I don’t know of any other interface that says it can do this. I would talk to Komodo – they are very helpful.



      • Reply

        Hola Angie,

        In order to use the driving controls of a wheelchair to control an iPad, iPod Touch, iPhone or Android device the chair needs to be equipped with an Environmental Control Unit (ECU) box, also known as an input/output module. This is an add-on for wheelchairs that allows the chair to control external devices. The Tecla Shield connects to the ECU box with a serial cable.

        Once the Tecla Shield is connected you just need to select a mode. The Tecla Shield can be used in conjunction with Switch Control or VoiceOver to control the entire device, not just “switch-accessible” apps. However the Tecla Shield also has a mode that works with those “switch-accessible” apps that use Space and Enter as switch inputs just controlling that specific app.

        Feel free to contact us at info@kmo.do if you require more information or have any other question.


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