September 25, 2023

Github Business

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25 Years Of Hardware Manufacturing In Plovdiv

Plovdiv, Bulgaria has a long history of design and innovation going back at least 6000 years to cultures like the Thracians, Celts, and Romans. In the last decade it is also an important center for open hardware innovation — reviving the lost glory of the computer hardware industry from the former “Soviet bloc countries”. One of the companies in the region that has thrived is a 5000 square-meter microelectronics factory which you may have heard of before: Olimex.

Olimex has over 25 years of experience in designing, prototyping, and manufacturing printed circuit boards, components, and complete electronic products. Over the last decade it has evolved into a shining example of an open hardware company. We recently had the chance to visited Olimex and to meet its CEO, Tsvetan Usunov.


Mr. and Mrs. Usunov run Olimex as a family business

When our driver arrived to pick us up, we asked, “Who actually is Olimex?” and were pleasantly surprised with the response: “I’m Olimex”. It was an interesting way to meet the head of a company, but it gave us a fast introduction to his personal philosophy. Tsvetan Usunov always wanted to do what he enjoys: developing hardware. Business was never his main goal.

Tsvetan has a history of going against the flow and taking risks. The name he gave to the company “Olimex” in 1991 has a deeper meaning, one that echoes the social and political changes in Bulgaria after the collapse of communism in Eastern and Central Europe destroyed its rather inefficient manufacturing sector. Tsvetan was just finishing Technical University in Plovdiv when the fall of communism exposed all the ills of centrally planned economy and industry:

All my friends were disenchanted with the prospect of some engineering jobs in a collapsing economy and decided to start various import-export businesses. From a country producing computers and being in many ways self-sufficient, Bulgaria became a country heavily dependent on imports without any production, falling even more into poverty. I started to joke with my friends at the university, who were massively leaving their expertise in microelectronics to become salesmen in the “buy cheap sell, expensive” economy, and I called my company “All-import-export”. The word “Allimex” was difficult for the post office personnel to write down because Bulgarian is a phonetic language and people write the sounds they hear, which led to the change of the name into the present “Olimex”.


Olimex is a buzzing hardware manufacturing paradise with pick and place machines, reflow ovens, and optical inspection rigs. The infrastructure and the 40 person team support a motivated local and international network of hardware developers interested in building and using an affordable and open “mini-computer” called OLinuXino. But the company was very different when it began.

Tsvetan started Olimex in 1991, developing and manufacturing for companies in the Turkish market. They needed a reliable manufacturer to produce boards for kitchen appliances. Tsvetan purchased land and buildings from a furniture hinge factory which had begun to collapse to use as his factory. In the early 2000, when the whole market changed and moved to China, Tsvetan transformed his business-to-business model to serve more niche customers.

His new focus became development boards. Traditionally these would be sold to only hardware developers, but at the time open hardware was just starting to grow. Many new customers, from software professionals interested in hardware to industrial designers to general enthusiasts, would be buying development boards. As his business grew, so did the footprint of Olimex.

In the present Olimex is recognized as an approved Third Party Hardware Developer by many leading companies including Texas Istruments, Maxim Integrated, Atmel, Philips Semiconductors, and ST Microelectronics. Olimex has over 30,000 active customer accounts and their Linux DIY computers and boards feed various from IoT projects, ATM cash machines, and are used even by car manufacturers.

Open Hardware

olimex-board-on-displayThe open hardware model for Tsvetan means more than just publishing the final designs. He is interested in having a continuous conversation with his peers from the start of the project. This forms a “participatory and collaborative design” and it leads to a better product.

Olimex keeps a very active GitHub page. This extends to the CAD files which are available in pre-fab stages before any hardware revision is out. Tsvetan mentions this is considered a big no-no in the crowdfunding circles, and often other supposedly open hardware projects sometimes choose a policy of ‘CAD will be available when the first batch of products are shipped’. Olimex has directly benefited from sharing early, as community members sometimes catch bugs that can be fixed before going to production.

Inspired by the Exclusivity of Raspberry Pi

OSHW became a mission for Tsvetan back in 2012 when he wanted to see and work with the newly announced Raspberry Pi computer (RPi). He describes the scene at the Farnell distributor booth when the RPI foundation showed just two boards and promised to ship them in 16 weeks. This biggest event in embedded technology became a disappointment for him: he was a board manufacturer but couldn’t actually source the Broadcom chips found on the RPis and couldn’t iterate on the original design.

A20 OLinuXino LIME
A20 OLinuXino LIME

He decided to create a truly open source Linux mini-computer, which would be cheap, fast, and most importantly, producible anywhere around the world. The result is called “Lime” as a response to RPi. The “fruit” board wars are still ongoing. While the idea of DIY Linux computer-on-board started out from frustration, the individual steps in building it are all small and useful lessons in how to balance pricing, scalability and design and involve the community in the process:

I started by selecting the right processor as a replacement to RPi BGA, which is hard to solder and virtual impossible to source in the open markets, and my first choice was Freescale iMX233 TQFP package. This led to several Micro, Nano, Mini and Maxi boards that run Arch and Debian Linux with Kernel 3.13. Sharing the designs from the right start proved to be the right idea because it involved people from countries with strict import procedures, especially Brazil and Russian, who printed the board and tested the design to spot the issues and took part in the improvement. The motivation for them were mainly the difficulties in importing electronic products and components, which makes DIY, locally produced boards the only way.

The original board had a modest specification of 64 Mb of RAM, 454 MHz and it was slow in comparison to the RPi. This led to the next decision to switch to Allwinner’s A13 processor, which is four times faster and utilizes Cortex A8 and Micro WiFi. It was still not the fastest processor, but a good compromise with only 176 solder pads. The next challenge was to create something even better than the RPi, particularly focusing on energy efficiency. This led to the Allwinner A20 processor which is a dual core, 1GHz chip that he paired with 1GB of RAM. The price wars RPi was officially announced by calling this board the OLinuXino Lime.

The whole story is captured in one of Tsvetan’s talks at the FOSDEM conference last year where he explains how between February 2012 and the beginning of 2014 there were 14 different OlinuXino boards ranging in price from 20 to 60 Euros. It has helped many people learned the skills necessary to use Linux.

The future plan is to further optimize the price, speed, and availability of OlinuXino. Tsvetan is not worried about the availability of the chips since he developed good relations with the Chinese company Allwinner whose main market is tablets.

Community Involvement

Olimex has already done a lot to support a community interested in designing and building electronics. They have a growing online community of developers and designers with weekly challenges and an active social media presence. Locally, they organize monthly meetings in Plovdiv, Bulgaria,  where people come to show, discuss or collaborate on various hardware projects. They host a two month summer camp in which anyone can test the latest boards and start more serious OSHW projects. There is also an annual free and open-source software (and hardware) conference called TuxCom held at Olimex for mobile, embedded and wearable devices. This is modelled after FOSDEM, the main European all-things-open conference.

Roman ruins of Plovdiv
Roman ruins of Plovdiv

The open hardware events in Plovdiv often take place in the local hackafe, Hackerspace, which is just walking distance from the preserved ancient Roman theatre and the ruins of a Roman stadium beautifully integrated in a lively walking avenue.

That Plovdiv is becoming one of the world leaders in open hardware innovation and even innovation in manufacturing should not surprise us. Many ex-communist countries had very good engineering programs and also a thriving tinkering culture, partially because it was difficult to buy consumer goods and easier to DIY with neighbors and other enthusiasts. The OSHW and maker culture are embedded in the culture and there is even a museum dedicated to tinkering in Polna, Czech Republic, whose motto says “What tinkerers achieved in a totalitarian regime”. The “solutions” we see there resemble some of the present “makers projects”, such as the DIY satellite dishes, funny prototypes of an anti-migraine electronic kit, and loudspeakers made out of beer barrels.

The next stage for Olimex and Tsvetan is to support more education and grow the community locally, because they still seem to be known more abroad than at home. This year they supported OpenFest with a SMD PCB assembly workshop to teach kids how to make a binary watch, but there is still a lot to do. One big advantage of Plovdiv are the nearby Rhodopi mountains, which are not only beautiful, but also metaphorically important as the magical birthplace of Orpheus. This legendary musician and poet from the Greek myths was famous for his songs, which could allure “the trees, the savage animals, and even the insensate rocks, to follow him” according to Ovid. In many ways this should be the goal of the “artistic” OSHW movement and its embedded devices, which are also trying to give voice and sense to things and the world around and connect the worlds of humans and machines.

Denisa Kera_headshot
Denisa Kera
Yair Reshef

Denisa Kera (CZ, SG) is a philosopher and designer exploring prototypes as tools of ontological disobedience. In her day job as an academic she follows how open hardware supports open and citizen science advocacy, especially in the Global South. She is a member of Brmlab hackerspace in Prague.

Yair Reshef (IL) is an art technologist by trade, supplier and fabricator of rare and made-to-order hardware and software – electronics, optics, robotics, and other curiosities. He is currently working on TAMI attiny, a cheap(est) dev board at Tel Aviv Makerspace.