Need help with Camera multiplexer

[kwhite458]

Hello;
I recently acquired a 16 channel video multiplexer and I want to control the camera switching with an Arduino. According to the manual:

You can control the SEQUENCE, MULTISCREEN/QUAD SHIFT, and the camera selection buttons from a remote controller.
These functions are activated by contact with the ground terminal (open collector output or normally open contact).
• Connect the ALARM/REMOTE connector (pin 23) to the ground terminal as shown below. Switches 1 - 16 select the
cameras (they do not control the alarm input).
Notes:
• Any two or more switches closed at the same time will cause this unit to malfunction.
• SEQUENCE is assigned to switch 17 and MULTISCREEN/QUAD SHIFT to switch 18.
• When no operation is taking place, all switches except switch 19 must be open as shown below.

So basically I need to connect Pin 23 to any ONE of the other pins. What is the best way and/or cheapest way to do this using the outputs of an Arduino Mega?

 

[KrisBlueNZ]

Hi and welcome to Electronics Point

You need to provide open collector (or open drain) outputs that close to the 0V rail to activate the functions. This is done with NPN transistors or small-signal N-channel MOSFETs. I'll assume you will use transistors. You'll need one for each output. BC547B or 2N3904 are suitable.

Connect the emitter to the Arduino's 0V rail. This rail must also connect through to the 0V or ground rail of the video multiplexer unit.

Connect the collector to the input on the video multiplexer unit.

Connect the base through a resistor of around 10k to an output from the Arduino. When your firmware drives this output high, the transistor will be forward-biased and will conduct, pulling its collector down to about 0V and activating the input on the video multiplexer unit.

 

[kwhite458]

Thanks Kris, That is exactly what I needed. Searching this forum has already helped me a great deal. So glad I found this site.