Please pardon my ignorance but I’m currently working on a robotic platform & arm project and I need some help!
I need to control this LED Sequencer -> http://www.ledsequencer.com/2011/08/led-sequencer-9v-24v-12-channels-32.html
It has 4 push-buttons that changes it’s sequences and speed. I’m wondering if it is possible to control it using the Maestro Servo Controller eg. simulating a push-button effect from inside the program. I am currently using the Maestro Micro but I have a Mini also. I bought this RC switch https://www.pololu.com/catalog/product/752 thinking that it could do the job, but after reading more about it, I’m now a little unsure. Instead of spending the time and effort to hook it up and risk it failing and/or destroying my devices, I’m hoping someone can help advise me first.
Basically, the ideal effect for me is to hook it up to two of Maestro’s servo output channel, one channel controlling the up/down light-changing sequence while the second channel controlling the blinking speed. I’m also using the “Simple Motor controller” https://www.pololu.com/catalog/product/1373 on a separate 12v battery that drives the board and my geared motor, I’m also connecting this same 12v battery to my LED sequencer (which also drives the LEDs)
Is this Pololu RC switch that I bought the right thing to use? The output is digital and I don’t understand what it means. Can I connect 2 of these to one servo output channel and have it “press the switch” when it’s at high and “press the other” when it is at low? Also, do I have to connect the common ground from my 12v battery to the switch? (I’m using a separate 11.1v lipo on a 4A UBEC to drive the board and servos)
If this is not possible, can I utilize any of the other outputs or analogue channels to accomplish that? Or are there any other products that I can use? Anybody with a solution for me? Any help is very much appreciated!
Thanks in advance!
I don’t see a schematic for the sequencer so I can’t be sure about this advice: If the sequencer has a microcontroller (MCU) and the MCU’s logic voltage level is between 2.2 and 5V, and one leg of the switch is connected to an input on the MCU, then using the RC switch should work in place of one physical switch. I recommend not connecting the physical switch, or removing it, because if you press it while the RC switch is trying to drive the input in the opposite direction, it will create a short.
It sounds like you want to get 3 states from a single RC channel using the RC switches. I don’t think that is possible without additional circuits or microcontrollers. I can’t think of how to do it easily, and I don’t know of any product that does it.
Someone here pointed out that I missed an obvious thing you can do. If the sequencer works like I described in my last post, you can use digital outputs on the Maestro in place of the physical switches. You would use one Maestro channel per physical switch you want to swap out. You shouldn’t need to use the RC switch.
Thanks so much for your reply! It sounds like a simple solution!
Ryan, pardon my ignorance again, I don’t really understand the concept of a digital output and I can’t seem to find detailed explanations on the documentations. I understand that I can turn one of the servo output channels into a simple digital output, but how do I convert that into a simple latch or momentary switch, replacing the physical switch? Does it give it a small current to the output, completing the circuit? I don’t even know what I’m talking about!
Are you saying by assigning a channel as a digital output, it can act like a switch?
Could you help me a little more? What do I need to do exactly? The 3 pins on each channel, +,- & signal. Do I connect the positive and signal to the switch while connecting the common ground to the LED Sequencer? Or do I ignore the signal pin and just connect the + & -?
Aside from assigning that channel as a digital output, what other values do I need to alter?
I hope what I said made at least a little sense, otherwise it’s just too complicated for me.
Hey I just wanna add, you guys are great! I love your products and your prompt replies and support. I started from zero to something because of all the simple solutions you guys create, and I’m hooked ever since! Please continue to innovate! I look forward to all your cool new products!
Thanks again Ryan! Looking forward to your reply!
As you said, it sounds like you don’t know too much about electronics, so you will want to be very careful and try to learn as much as you can before connecting these electronics. What is going on is the Maestro’s microcontroller has some transistors inside it that let it connect the output to either 5V or GND (0V). This output is connected to the signal pin. Here is more information about using transistors as switches.
Please keep in mind that since I don’t have a schematic of the sequencer, there are a lot of guesses here that might be wrong:
If there is a microcontroller on the sequencer, it probably has an input pin connected to one leg of the physical switch that can sense if the voltage is low or high. When you press the switch, you connect either a low or high voltage directly to that input. When the switch is not pressed, probably a pullup/down resistor pulls the input to the other voltage. In this case, you would want to disconnect the switch, and connect the Maestro’s output to the sequencer microcontroller’s input. To do this though, you need to make sure the sequencer is operating at the same logic level as the Maestro, which is 5V. You also need to connect the grounds of the sequencer and the Maestro together.