SDI develops & manufactures control panels for doors and shutters

Printed circuit boards (PCBs)

SDI design circuit boards for - among other things - garage door control.

The PCB here is photographed on an engineer's formica table; that is a consequence of the honest marketing skills of an engineer, I am sure.

The board shown is the main control system for our Symbolic Instruments panel. Populated sparingly as shown, the board will be given a 40 pin microchip, power relays, a transformer, and various other parts.

SDI have use of an in-house CNC machine which can pick and place 0402 parts via suction, with the aid of a camera to assist the robotic motion. This machine is in the 'beta' state as yet. We also employ 0603 parts, placed by hand.

Soldering is conducted with a batch reflow oven; stencilling for the PCB solder paste is applied with a manual stencil machine.The resulting board gives a heck of a wallop, with 230V up to 5 Amps, and an on board rotary encoder and LED display for user programming - similar to the GfA method.

Our process is not exactly industrial scale - but we have almost total vertical integration. Every part is understood and developed in house. Our small scale - at present - allows for bespoke microchip programming and door control function - rather than large quantities. But that is not the horizon of our ambition!

Radio Frequency devices, by SDI

We also provide our own RF controller or handset, printed with our in house ABS 3d printers. These devices encode the signal in the keeloq protocol, and broadcast at 433.92MHz. The code, design and manufacture of these items is, of course, carried out in house. The board can accept just eight individual handsets at present - and each one is multichannel.

The SDI receiver will accept signals up to 50m away with clear line of sight. These devices are for plugging in to our Symbolic Instruments board, but may be adapted for other applications.

Infrared beam system, by SDI

Given the near monopoly of the market by Witt, Gewiss, and another German firm - we have decided to develop our own Optical Safety Edge system. That is, we do not need to purchase or use the complete miniature send and receive plugs from the usual manufacturers: we use our own. The IR system is in any case simply an infrared LED sender (such as is used on a TV remote) and an infrared receiver (also shaped to look like an LED).

The signal of the sending device must be modulated to work in bursts of several KHz in order that common sunlight does not interfere with the reception of the signal of a working sending device line (through the weatherseal rubber). This modulation and the decoding of it is acomplished by using a microchip inside the plug itself in the standard models. Ours is a large scale DIP chip located inside the plastic housing. Our device is the common curly helical cable wired model.

The main board of the control panel expects a voltage signal from the OSE system, via the green wire. When it does not get one, the control panel will not allow the door to close Automatic.

We have every reason to be proud of our development of an IR OSE device to rival the large continental manufacturers. However, our motivation was simply to avoid being 'ripped off' by them.

Here is the board populated

... and here it is in its case.

Proprietary Code and Schematics

As well as making these things, and designing the hardware - we also write the code and draft the schematics.

..One day the mega monopolies which have been allowed to drift into our world and blockade our democratic traditions will depart. And, enterprises which concentrate on making things, rather than those mega-enterprises which concentrate on squeezing more money from us and avoiding the law, will make way for devices like this!

In the meantime, please feel free to contact us with inquiries, proposals, or comments. Thanks.

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