MK161 discrete codes with modification

I am using my MK161 to control raising and lowering the screen for my home theater with an additional external relay.

When sending commands to multiple devices with remote control macros, you don’t want to toggle. If I am turning five things on, and one fails to receive the command, the user will press the ON button again - will the device that toggles turn off now? Every device should have discrete on and off commands for reliable operation.

I was a little frustrated that the MK161 only supports a toggle and not two discrete commands for each output. Ideally, you would have the option of programming separate on and off commands for each relay.

It is interesting that the MK161 has the option of a pulsed output. This got me thinking as to how to solve my problem. As I was planning on using an external DPDT relay anyways, I changed the RY2 output to normally closed by scraping off the NO relay lead, jumpering the NC relay lead to that terminal and connecting the NC common of the relay to the NO common. Now the RY1 output pulses closed and the RY2 output pulses open.

Unfortunately, I don’t have a method for posting an image with my schematic, so I will describe the connections and use a primitive diagram. Note that in this diagram, I have used periods (.) where I wish I could have used spaces, but leading spaces are deleted by the forum software. The external relay’s coil voltage is 12VDC so I can use one power supply for the external relay and for powering the board.

12V positive is connected to one terminal of both SK2 and SK3. The other side of these terminals are shown in my diagram. M is the coil of the external relay and right below is a NO contact, which acts as a standard hold circuit.

When RY1 is pulsed closed, it powers the external relay, closing it’s NO contact. Now, M is powered from the NC contact of RY2 going through the external relay’s NO contact.

When RY2 is pulsed open, the source of power for the hold circuit is interrupted and M is no longer powered.

SK2 ----|— (M) ----- 12V negative
…|
…|----| |----|
…|
SK3 ----------------|

I think it would be great if the kit was modified in one of two ways.

  1. Connect both commons of RY2 together. Have the builder install a jumper to choose NO or NC operation.
  2. Allow two discrete commands for each relay. Then I could control two devices!

Since neither of those are likely, you can follow this procedure to get the desired result.

SoundOfMind,

Nice mod on the MK161. I just bought one for my home theater to tun on/off a DIY LED Clock above my screen. Your mod would not be used for this project but do plan to use it for something else in my HT soon.

Could I trouble you for a schematic/pic of your mod? I believe I understand but having a really pic would help.

My email is stwithey at hotmail dot com.

I do not check this email that regularly – so please post here so that I know to go check this account.

Thanks again.

Steve