Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: Selenaut-14 on July 04, 2010, 11:58:16 PM

Title: $50 robot: LED motor status?
Post by: Selenaut-14 on July 04, 2010, 11:58:16 PM
I feel like I am asking a very stupid question.
  Would adding an LED and appropriate resistor in a correct fashion to the circuit of a servo on the return trip to the microcontroller work so that it would light up when that servo is being used?
  Note that I am using the circuitry for the $50 dollar robot with this mod only... For now... And that I am a complete rookie to this.
PS: hello, I am new around here. While I am good at building the mechanical aspects of robots, I suck at circuitry. So come asking me things about frames and torque and things like that. I am NOT the go-to guy for circuits.
Title: Re: $50 robot: LED motor status?
Post by: Alfa_Zulu on July 05, 2010, 06:43:55 AM
ah, no.

the only communication between the mcu and the servo is through the pulse output which is send to the servo.

the servo + and - go straight to the regulator so no communication, however you could connect an led to another output pin and - (ie using an output from the muc as + and - on the bus) then you could write extra code to tell the mcu to output 5V on this in if this servo is being used, or something along those lines.

you could probably do it another way but this is how I'd do it.  ;D
Title: Re: $50 robot: LED motor status?
Post by: Selenaut-14 on July 05, 2010, 07:58:46 AM
Okay. I was going to use it to make sure the motors were working properly.
Title: Re: $50 robot: LED motor status?
Post by: Soeren on July 05, 2010, 11:18:25 AM
Hi,

If you use a re-triggerable monoflop (can be made with a 555 or eg. a 4093) and set the period to say 35..40ms and then let it drive the LED, you will have visual indication when there is a signal to the servo.
Problem is, that there is signal to the servo when it's stopped, unless you drop the signal on purpose.

If you only want it to light when there is movement, you could use a small microcontroller to detect signals that are above or below 1.5ms (but I gather it's a bit over your current skill level).

If it's just for checking whether there's signals going to the servo, the re-triggerable monoflop will do.
Title: Re: $50 robot: LED motor status?
Post by: Selenaut-14 on July 05, 2010, 11:29:10 PM
Hey, on the subject if dumb questions, can you get the
photovore to follow a laser pointer?
Title: Re: $50 robot: LED motor status?
Post by: Alfa_Zulu on July 05, 2010, 11:59:42 PM
im sure you could with a camera, make it move towards a red dot.

although if your wearing red shorts it may chase after you, rename it to the bull  ;D
Title: Re: $50 robot: LED motor status?
Post by: Choco_liger on July 06, 2010, 04:29:13 AM
A photovore follows light.
So if you shine the laser pointer near the CdS cells then, it'll follow it.

I've tried with my flashlight, and it works. It's quite fun to play with.
Title: Re: $50 robot: LED motor status?
Post by: Alfa_Zulu on July 06, 2010, 04:44:21 AM
but surely with a laser pointer having such a small beam would be difficult to control it, especially since you could probably only shine light in one of the cells at an instance.