Access Control using iButtons

Written by Al Markočič on April 20, 2017

We developed access control hardware with mobile data synchronization using iButtons.

Constructing for those who construct

Since we provide a wide range of R&D services in the field of electronics, we receive inquiries from many different fields. This time, we were contacted by one of the largest Slovenian construction companies. They required a device for access control of multiple entry points to their main facility. They were quite confindent what the device needed to incorporate: iButton readers and a GSM interface. The company already had a similar device in use, but unfortunately it was not up to the task.

We approach each project individually and try to offer the best experience possible. For this project, we wanted to make sure that we were not developing an already existing device as it would be quite pointless to develop something that is already on the market and can be bought. Developing a product is always more expensive than buying something that has already been developed and is sold, preferably in large quantities.

Developing the hardware - and making it waterproof

After doing our homework and confirming that such access control device combining an iButton reader and a GSM interface did not exist, we started planning the development. We derived from received specifications that included an iButton reader, GSM interface for real-time synchronization of iButtons with allowed access, and also an ethernet connection. Of course, in order to unlock doors relays were required, too. So we carefully developed the PCB and enjoyed the results.

As this device we were developing was not meant to be a mass-produced product, we had to find an existing industrial housing that would accomodate the hardware. Based on our experience with a reliable and robust Japanese housing producer, we chose one of their enclosures. Since the case needed to be IP65-rated, the decision was quite straightforward. Nevertheless, we still had to run some tests just to be sure (but to be honest, our engineers probably just wanted to play with the water).


We are quite proud that despite using an industrial enclosure, the final product looks nice and sleek. With the iButton reader being centered and the only interface on the device, we can say that the user experience is pretty much the best we could do: the worker is only required to approach the iButton, and the device does all the rest.

Due to its popularity, we actually suggested RFID to the client as an alternative but they explained to us that their workers were already carrying iButtons and they did not want to change that. Of course, that made perfect sense.

Boutique production ...and deployment, too!

A definite advantage of this project was that we were not only developing some device, but were also installing it in production which meant that we could see the work processes in person. Furthermore, since the client was satisfied with what we delivered, they instructed us to develop another device for registering personnel involved in fluid refueling processes. The use of Linux enabled rapid development of this useful terminal.


Another advantage of production installations is the ability to fine-tune your products in real environment where things normally tend to work somehow differently than in your development facility. This is why we always included a firmware guy in every field trip we have had and it was not that uncommon to see an access control terminal with its case open, and some guy with a laptop geeking nearby. Cumbersome as it may have looked, this enabled us to support our client's work processes in every detail and fine-tune the access control terminals.



Projects that require us to participate on field have great added value for both us, the developers, and the client. Being able to see work processes in person provides better insight and you can improve your devices in order to best support what the users need. And get some fresh air, too!

Does your project require a full-stack engineering team?

Drop us a line and we will be more than happy to work on an exciting new project with you.

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