Circular LED Bargraphs

Using Arduino LEDs and Multiplexing
#1

So I'm trying to use this Circular LED Bargraphs display to show the position of a servo, or better of as a throttle gauge. https://www.sparkfun.com/products/10595. Spark fun also has a LED RingCoder Breakout board available https://www.sparkfun.com/products/11040. I need to figure out some way I can use this circular led without having to use to be restricted to the rotary encoder.

I'm using the arduino lily pad as a controller, a flex sensor for input signal and a servo for output. But I want the Circular LED Bargraphs to display the position of the servo.

I hope this is adequate information to prompt a response.

#2

Just use the led and forget about the breakout board. Treat them like normal common cathode LEDs.

#3

The sparkfun board simply drives the leds via two shift registers, which you can do on your own as well - if you want to do go down that route. Or you can just drive them with 16 io pins.

#4

I would use it straight like a regular led but I need a breadboard for it and the pins are not standard in spacing. But I can figure something out. But as far as a code would go any one have an idea I'm not finding any luck for this led display.

#5

I'm not finding any luck for this led display.

The right code to drive it depends on how you intend to drive it.

#6

Ok, I'm going to have to look into that. I was hoping to hook it up straight to the lily pad but Ill look in to a driver for this led.

#7

No you missunderstand, you can drive it directly from your arduino pins, how do you want the LEDs to look. For a servo do you want to have an led lit at the same angle as the servo. If so it is simply a matter of using the map function to convert the angle into an led position. Do you have 16 pins free on the lily pad?

#8

Oh I can? Then I need to figure it out. I'm still figuring out a diagram before I do final connections. As fa as connections go the lily has ( 4 digital, 6 digital pwm ,1thx,1rx, 4 anologs and 2 power) the led display has (16 pins with 4 more for com) my. My problem is I'm not sure how to connect them properly, I was more on hoping the resistance from the flex sensor to direct the led display.

I need to Take the same signal from the sensor and translate it into 2 set of commands, one is for the flex sensor to move the servo and the second is for the flex sensor to led display. I was thinking using the level of resistance and map that out to the led display.

The led display is going to be my visual warning of how much throttle I'm using no mater what position my servo is in. So I need It to light up each led as the throttle increases.

Ps. I appoligise now if I'm not making any sense, I'm just getting in to this and I'm still learning. Thnx for the input

#9

Check out the bar graph tutorial on the home page. Treat it like that but just in a circle.

#10

Looks like you don't have enough output pins, simply use two shift registers. Connect the LEDs to the outputs through a 270R resistor on each LED.

#11

Yep, I was expecting to use a shift register. I was looking at https://www.sparkfun.com/products/733? Seems about right, but then this breadboard https://www.sparkfun.com/products/11040 already has a 2 shift registers on it but I need to find a way to bypass the rotary encoder part. But as far as the resistors to do they have to be 270 ohm or can I get https://www.sparkfun.com/products/8377 even it's just a Ted bigger.

#12

but I need to find a way to bypass the rotary encoder part.

No need to do anything it is not coupled to the LEDs at all. Just don't wire up a rotary encoder.

But as far as the resistors to do they have to be 270 ohm

The schematic says they are 330R which is just as good in this application.

#13

Excellent, so I'm waiting for the breadboard to come in so I can figure out the connections to the rest of the system https://www.sparkfun.com/products/11040 But I still have o figure out the code for the board it self. If I'm eliminating the rotary encoder from the board can the pins from the board be enought for it to work straight from the lily pad? If so what code can I use (how can I map it out) the example code they provide is meant more if the rotary encoder is involved.

#14

Just code that talks to two shift registers. Well just use the code for one to start with and then expand it to two. http://www.arduino.cc/en/Tutorial/ShiftOut Look at the schematic to see where your shift register pins are wired to and compare that with the tutorial and make changes to the sketch if you need to.

#15

Awesome this is what I'm talking about, ok I'm going to review all this and try it out after I get the breadboard in. Just need figure out the connections of everything then I'm on to writing the code using the example you gave me. I'll return if any issue arise.

#16