Decimal to Binary to Hexadecimal Converter

An overly mechanical device that will convert decimal numbers to binary and hexadecimal.

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It is using an ESP32 equipped with an OLED display, two mechanical 7 segment displays and 14 relays. I'm using two NXP MC33996's along with the DPDT relays in an h-bridge configuration. To set each segment it need at least a 1ms pulse and to reset the segment it needs to be pulsed with the opposite polarity. This was a proof of concept before I designed a much larger clock with 6 digits and 46 relays with two sets of flip dots as colons. I will released all build files and source code soon.

Converter Prototype KiCAD Build

These are the build files for the exact board seen in video. The schematic below is updated to include rework I had to do. MC33996 reset pin needs to be connected to reset of the ESP32 or 3.3V. I added shottky diodes to the relays and TVS diodes to the individual segment coils. Also changed the SOPWR pin on the MC33996 from 12V to 3.3V. So keep in mind if you want to use these gerbers as is, you will need to rework the board. The footprint on my ESP32 board was mirrors so I had to add the protoboard with the pins swapped.

Zip Archive - 330.91 kB - 01/29/2018 at 18:20


Converter Schematic.pdf

Schematic for converter that includes changes I made to improve the reliability of the circuit.

Adobe Portable Document Format - 323.29 kB - 01/29/2018 at 18:10



Source Code for the converter

ino - 52.13 kB - 01/29/2018 at 13:25


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    Keep in mind that the manufacturer recommend a resting period of 900ms before driving the same segment again and my code is driving them faster than that.  I'm also driving the segments with 12V instead of the recommended 16V-19V without any issues.  The datasheet says that the max coil temperature is 95C and my coils are not getting any where near that temperature so it could be fine as is.  This may be because I'm driving them with a lower voltage.

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Anthony Garofalo wrote 01/29/2018 at 18:34 point

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