product analyzed



Dactyls app logo.
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Categories assigned to this product within the main category Technology.


Categories assigned to this product within the main category Needs.

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Below is the video of the review.

What does it consist of:

Dactyls is an application developed by the Center for Typhlotechnology and Innovation (ONCE), the Technical Unit for Deafblindness (ONCE) and the Complutense University of Madrid, which aims to publicize the Dactyls communication system, which combines the use of the tactile dactylological alphabet , tactile signs and rules that regulate their operation. This system was created by Daniel Álvarez, who is a deafblind person and the first adviser of the ONCE Technical Unit for Deafblindness.

The application presents a simple interface, with the different signs grouped by categories, which present videos demonstrating their use. It also presents a documentation section, which provides in-depth information on the Dactyls system and deafblindness.

It is a free app and is available on iOS and Android devices. It also has a web version.

Next, we provide two videos from the ONCE YouTube channel that briefly explain what the Dactyls system consists of and the application they have created to publicize said system:



Forms of acquisition:

The app is available to download for free from the Android Play Store and the iOS App Store.

Download the Android version at the following link:

Image from Google Play. Pressing it opens a new window of the Dactyls application in the Play Store.

Download the iOS version at the following link:

App Store image. Pressing it opens a new window with the Dactyls page in the App Store.

In addition, the application also presents a web version, and it can be accessed through the following link:

To make any queries, the developers provide the email address of the ONCE Technical Unit for Deafblindness:

On the page of the ONCE Typhlotechnology and Innovation Center ( you can consult more information about this and other projects that are carried out.


Technical assessment:

Author: Daniel Guillermo Alonso

Date: May 2022

For this analysis we have used version 1.0.1 (Updated on October 22, 2021) in a smartphone Android.

User interface

When you open the application you can see that it has a design that highlights clarity and minimalism, with a category where you can see the available signs and another called documentation where you can find information about the Dactyls system and deafblindness. Below, we delve into the options that are available within the two categories mentioned.

Image showing the menu that appears when opening Dactyls.


Signos: In this category you can consult and learn the different signs of the Dactyls system, and depending on the search you want to do, different options are offered:

  • Searcher: This option allows us to do a manual search for the signs we want.

Image showing the search section, with different signs of daily activities.

  • Themes: Here we can find all the signs of the Dactyls system included in the application grouped by general themes.

Image showing the themes section.

  • Categories: It is the same concept as grouping by subject, but in this case they are grouped by grammatical categories, expressions, groups of words and groups of signs.

Image showing the categories section in the main menu.

  • Dactylological: Here you can consult the dactylological alphabet in Spanish, which is the most used among deafblind people to communicate.

Image that shows the category of the dactylological alphabet in the app.

On the other hand, it should be mentioned that every time we enter a specific sign, the following interface is displayed:

Image showing the January page as an example to show the interface.

This interface is very complete, playing a video with the execution of the selected sign that can be seen from a front view and a side view, and providing a written description that explains step by step how to perform said sign.

Pressing the icon  Play icon located on the left of the screen.we can play, pause or repeat the video and withIcon very similar to play but with a stick to the left. This is located to the right of the previous one. the same but playing the video in slow motion. If we pressSquare icon.the video will be played in full screen. Pressing the settings icon Icon represented by a gear, located to the right of the screen. We will be able to select if we want to load the video with data and choose the video quality (High at 1080p, medium at 720p or low at 360p) for when we play it via Wifi and for when we do it through data.

Documentation: In this category we can obtain detailed information about the Dactyls system and deafblindness. The information is classified by different themes, which are: information about the Dactyls system (by clicking on the “Dactyls system”), information about deafblindness (by clicking on “Deafblindness”), documentation about how to teach signs (by clicking on “ Enseñanza del Dactyls") and data about the application and its version (Clicking "About").

Image showing what could be found in the documentation section, in this case information about the Dactyls system.

Technical performance


The application has not presented any failure or blockage during the analysis period, being able to navigate through it quickly and smoothly.

Consumer goods

During the analysis, no significant increase in battery consumption was observed. The data consumption will only be necessary to load the demonstrative videos of each sign.

Versatility and compatibility

Dactyls is a multiplatform application, and we can access it:

  • Through your application smartphone o tablet with Android operating system version 4.1 or later.
  • Via iPhone or iPod touch running iOS version 12.0 or later.
  • Via iPad with a version of iPadOS 12.0 or later.
  • Via Mac with macOS 11.0 or later and with the Apple M1 chip.
  • Through its web version.

Security and privacy

According to what the application itself indicates in its "About" section: "Through this App ONCE does not collect or process personal data of users."



Regarding the interface, it presents a simple and easy-to-use design, with icons and texts of an acceptable size.

The app can be used with screen readers like TalkBack for Android and VoiceOver for iOS, increasing accessibility for people with low or no vision.

In this review we have tested the TalkBack screen reader for your version of Android and we have verified that all the options, buttons and texts are correctly labeled and will be pronounced when you pass your finger over them.


Dactyls is an application that, through a simple interface, manages to be very effective in its main objective: to make the Dactyls communication system known in a clear and complete way to facilitate interaction with deafblind people. To do this, it provides useful and extensive documentation, as well as detailed information on each sign accompanied by videos for better understanding.

It is, therefore, a very useful application if what you are looking for is to learn about deafblindness and the communication systems used by deafblind people, especially the Dactyls system.


  • Its simplicity, with very clean and clear menus that leave no room for error.
  • The amount of information that is provided about the Dactyls system, providing demonstration videos and detailed explanations on how to make each sign.
  • The informative mission that this application supposes, promoting making known to the greatest possible number of people a very useful form of communication with people with deafblindness.

Improvement points

  • Perhaps in some sections, such as the indexes of the documentation topics, a slightly more attractive and attractive design is missing.


Technical evaluation scores.

Design and manufacturing:
This section refers to the physical aspects and details of the manufacturing of the technological product
Technical benefits:
Description of the quality of the technical specifications of the technological solution
User experience:
This criterion is linked to the user's assessment when relating to the technical product or application.
It is the degree to which people can use or access a product, technological solution or service, regardless of their technical, cognitive or physical abilities

Social valuation:

Social valuation scores.

Impact and utility:
This item has not been rated/5
Describes to what extent the functionalities of the product are useful and impact on improving the life of the user
Design and Ergonomics:
This item has not been rated/5
Assessment of how the design of the technological solution adapts to the person to achieve greater comfort and efficiency when using it
Usability and accessibility:
This item has not been rated/5
Possibility of the device to be used, understood and taken advantage of under equal conditions for anyone
Ease of acquisition:
This item has not been rated/5
It refers to the possibilities of accessing and acquiring a technological solution by the user.

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