Getting serial data from an old spectrophotometer

[Jure Spiler] Occupied an old spectrophotometer, which measures light absorption and transmission in a sample. It was difficult to extract data from the device, especially since the model in question was an educational version that lacked some functionality. However, perseverance got the old machine to talk happily with a PC.

After pre-testing with sniffing the signals sent to the LCD, [Jure] Have done some more research. It was found that a particularly expensive cable could be connected to the parallel port of the device and provide serial data at a price of less than € 356 euros. Now knowing there was a serial output, [Jure] Was able to find the desired data stream.

Connecting a logic analyzer to the machine with a “parallel port” indicates that the device will actually send serial data through a specific pin on the port. The strategy that made it difficult was that it was in inverted RS232 form. Thus, a common TTL electronic signal pole connected to a USB-TTL adapter has been used to communicate with a modern PC.

With this achievement, [Jure] A simple VB6 program was able to whip the data from the spectrometer and place it in a CSV file for further analysis. There is even a program to graph data from the bat, which makes using the scientific instrument easier and faster than ever before!

Often, hacking old scientific hardware like this is not particularly difficult. It’s usually hard enough for busy scientists to stamp up cash for fancy adapters and cables, when there’s no match for dedicated hackers!

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