Wendy
11-12-2011, 04:38 AM
Hello all,
When I started with the PoKeys cards, I told you that these cards can do anything we need in cockpit building. So what I did was experiment a little bit with 7-segment displays and here are the results.
The test I have made is only an example, I did not have enough displays to show you the full range of 16 displays that can be driven with the PoKeys cards.
You can drive two groups of 8 displays, every group is connected by 3 ports on the PoKeys. That is only 6 ports to drive 16 displays.
How does it all work…
All works via multiplexing the same principle as most of the other displays work. Every segment of all the displays are connected to each other and connected to the card with 8 wires (7 segments and the decimal point). The common cathodes have one wire from every display that goes to the board. The multiplexing system is build in the PoKeys card and updates the displays fast and without any flickering. All can be driven from custom software very easy. I did these tests also, but cannot show this because I have no video camera. If interested, just ask me for the software code.
To make this all work you need a small circuit board as in the picture populated with a few cheap (a few euro) integrated circuits. Each board can drive 8 displays. Depending on the software on the pc side you could for example use 3 for the heading on the MCP and another 5 for altitude or any other purpose.
What about dimming the displays? If you power the board trough a PWM output on the PoKeys then you can also adjust the brightness of the displays as the driver IC works between 2 and 6 volt. Or you could use any other means to regulate the voltage on the driver board.
I had a lot of fun experimenting with these displays and the nice thing is that is works beautifull.
Just a quick reminder to what we have until now with PoKeys cards, so we have the USB and Ethernet interface, digital in/out, high power led outputs trough my LED extension board, analog inputs, PWM outputs and now we also have 7 segment displays compatible with the existing boards of OC and the displays are also common cathode like the Kingbright SC36.
And the best thing of all, it is the user of the PoKeys card that decide what the card is going to be used for. One card for all the different types of ins and outs.
I will be offering factory made boards on my website very soon.
Kind regards, Wendy
http://www.flightsimparts.eu/images/PoKeys_7Segment_Extention.jpg
When I started with the PoKeys cards, I told you that these cards can do anything we need in cockpit building. So what I did was experiment a little bit with 7-segment displays and here are the results.
The test I have made is only an example, I did not have enough displays to show you the full range of 16 displays that can be driven with the PoKeys cards.
You can drive two groups of 8 displays, every group is connected by 3 ports on the PoKeys. That is only 6 ports to drive 16 displays.
How does it all work…
All works via multiplexing the same principle as most of the other displays work. Every segment of all the displays are connected to each other and connected to the card with 8 wires (7 segments and the decimal point). The common cathodes have one wire from every display that goes to the board. The multiplexing system is build in the PoKeys card and updates the displays fast and without any flickering. All can be driven from custom software very easy. I did these tests also, but cannot show this because I have no video camera. If interested, just ask me for the software code.
To make this all work you need a small circuit board as in the picture populated with a few cheap (a few euro) integrated circuits. Each board can drive 8 displays. Depending on the software on the pc side you could for example use 3 for the heading on the MCP and another 5 for altitude or any other purpose.
What about dimming the displays? If you power the board trough a PWM output on the PoKeys then you can also adjust the brightness of the displays as the driver IC works between 2 and 6 volt. Or you could use any other means to regulate the voltage on the driver board.
I had a lot of fun experimenting with these displays and the nice thing is that is works beautifull.
Just a quick reminder to what we have until now with PoKeys cards, so we have the USB and Ethernet interface, digital in/out, high power led outputs trough my LED extension board, analog inputs, PWM outputs and now we also have 7 segment displays compatible with the existing boards of OC and the displays are also common cathode like the Kingbright SC36.
And the best thing of all, it is the user of the PoKeys card that decide what the card is going to be used for. One card for all the different types of ins and outs.
I will be offering factory made boards on my website very soon.
Kind regards, Wendy
http://www.flightsimparts.eu/images/PoKeys_7Segment_Extention.jpg