completing button circuits in an RF remote, having Arduino "push" buttons.

I have a cheap RF remote that controls an LED display. The button cover easily peels off and I can trigger the buttons by gently pressing a piece of solder over the interlacing connections for each button. Cool!

How might I complete this connection for 13 or so of these buttons via Arduino?

The remote uses a 3V lithium battery. I was thinking about taking out the battery and soldering on connections to the Arduino/breadboard. I guess I need to reduce the Arduino Uno digital signal voltage from (3.3v or 5v?) to 3V (resistor math hmm). Then maybe connect ground to ground side of buttons. I'm still a bit fuzzy on how to best close the connection.

Any thoughts on how to best proceed? By controlling the remote with an Arduino, I can automate my little light show based on connected events (yeah!).

Here's the flip side if you want to see it:

Thanks for taking a look in advance.

UPDATE: The lithium battery is measuring at 3.19V. Maybe I don't need to downgrade 3.3V or digital output pins. I have an Artemis ATP RedBoard handy that has 3.3v pins.

You need to decode the matrix to know how to proceed. I can't do that for you as it is too late at night and your first photo is useless. :roll_eyes:

You need to take photos in outside daylight (unless you have experience and a proper photo studio and equipment) but not direct sun.

Once you understand the matrix, you use one or more of the 74HC4066/ 74HC4051 devices to emulate necessary button presses. Note however that this switch IC (operating at 5 V) must always be powered whenever the remote is powered (which you can generally do from the 3.3 V output of an Arduino) and of course the negatives of the two devices are connected together.

Good thoughts. Here are new images:

  • ponders the matrix (will update as I progress)

UPDATE: Based on related searches, this "digital MUX breakout" looks like it could make the switch stuff happen for all mentioned buttons? Now I'm trying to figure out "common" in the matrix. This stuff is new to me, very fascinating though. Let's see if we can crack this puzzle...

UPDATE: Every time I look at this on a break, it makes more sense. I'll try to respond with a diagram of what needs to be active per button as soon as I can.

UPDATE: Matrix decoder ring progresses well. Standby for a mapping of things with further questions. :smiley:

Progress! Here's my attempt at decoding the remote. I don't understand The +/- flow of things yet, however it's good progress for discussion. The first button listed (power button) was convoluted as the circuit went under the chip. I can skip this one for now.

(see attachment for larger version)

Thanks again for taking a look!

UPDATE: I realize that I should decode ALL buttons so that I can better figure out which connections are from power source. Sending an updated chart shortly...

Here's an updated chart with ALL buttons:

(see attachment for larger image)

That leaves these remaining pins that go under the chip:


One is the mystery button pin, one is positive, one negative, one unused. I bet the one on the bottom right is the button pin, the one above that is positive, then negative on the top right. The one on the left seems unused?

At this point I'm looking for additional ideas on what to do next. I'll keep chipping at it in the meantime.


It is not a RF remote but IR remote.

One option is read the output of the remote, reverse engineer the protocol (a logic analyzer is handy for this) let Arduino transmit the wanted signals directly.

Hello Smajdalf,
Thanks for the response. I had thought that initially myself and even tested with an IR receiver, picking up other IR remote signals yet not this remote before realizing it was RF. This is just emitting light in the red LED at the front while the RF signal is being emitted from the silver rounded rectangle widget at the front corner. I can point the remote in any direction and the nearby LED display will respond.

For learning purposes, I hope to make use of the remote I have handy (and I’m learning a lot!). I feel like I’m close. Any additional ideas on how to proceed?

Opto-isolators might work.