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Asked — Edited

Sound And Servo Control Bp Talk Board

I have the BP talk board that controls the servo by sound. If I plug a headset male plug into my headphone on the PC and run it to the talk board the servo works fine but I lose the sound. Should I split the cable and run a speaker in parallel with this so I can get the sound back or does does the software have an option to not shut off the PC's speaker. Bottom line I need to hear the voice coming from computer.

I guess the other option is to leave headset port on PC along and put a mic on the talk board but I really don't want this because of background noise.

Frank, EZ Ver 4


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Thanks that what I thought but wasn't sure what DJ meant in his post.

What is a sound servo?

@d.cochran EZB would be a good demo for students during National Engineers Week... Which was one of the main reasons why I purchased the kit. That and plus I had omni bot collecting dust.:)

Sound servo is a control within ARC that makes a regular servo move with sound... You can use it to control a servo in a robots jaw to make him look like he is actually talking....
@Richard R,

That would come in handy actually -- but I'm still a few weeks away from that. I just got him to move with a new set of gears:)

Would it possible use the sound servo to trigger LEDs instead of servos?



Would it possible use the sound servo to trigger LEDs instead of servos?

Not directly, but the sound servo object also sets a variable "$SoundValue" which you could use in a script which adjusts the PWM of a digital port with an LED plugged in, so the louder the sound, the brighter the LED glows (or you could just have it flash on and off, or if using an array of LED's and a TIP120 circuit to power them all on and off... virtually endless possibilities).

@thetechguru My goal is to make the mouth light up when there's sound through the EZB.
One LED or many? Just on and off, or brighter the louder the sound?

What you want to do is possible. If you want step by step instructions, I would need a lot more information about what you want to do and what you are trying to do it with.

I have one of these... They respond to sound levels flashing a led or any other 12v light according to the sound level... Sound sensor LED


I have one of these... They respond to sound levels flashing a led or any other 12v light according to the sound level... Sound sensor LED

that is a nice, simple, and cheap solution. Sometimes I get too wrapped up in figuring out how to do something with the EZ-B when a super simple and inexpensive solution already exists that could work beside, rather than as part of it.

Ha, Ha @Alan.. During the Apollo missions the American astronauts took expensive complicate nitrogen pressurized pens into space to compensate for writing in zero gravity... The soviets took pencils..... and probably a lot of vodka too...:P


During the Apollo missions the American astronauts took expensive complicate nitrogen pressurized pens into space to compensate for writing in zero gravity... The soviets took pencils..... and probably a lot of vodka too...

Actually, that is a legend (well, not the part about Vodka), but it makes a good point.

I have asked @Steve G to pop in here since he is doing something very similar in his K9 2.0 project, and no sense re-inventing the wheel. I absolutely know how to do this with an EZ-B and a separate digital port for each LED. I am not much of a circuit wizard, but I think I know how to wire the LED's to use either a single digital port or the device Richard linked to have a similar effect (where the center is brighter than the edges, and all get brighter, or as you move out toward the edges turn on based on the volume or inflection of the speech), but I would like to hear from someone who has already done it before I start wiring things up and writing scripts.

Having seen Steve G's K9, I may want to do something similar with my Steampunk dog, so I am happy to help figure this out.

United Kingdom

As promised, here is how I did K-9's mouth. Some may say it's cheating but because of limited funds at the time during the build, and being rather new at this, I went for the K.I.S.S way of doing it. :P

Quite simply, I purchased a 3 wire sound responsive EL wiring kit, drilled holes is a peace of plastic (originally wood) and threaded the wires through. The different colours seem to have different frequency responses which made the bouncing "KITT" voice box effect, which was a bonus and unexpected. I extended the power cables, threaded through K-9's neck in the the body, and placed the battery pack/microphone near the on-board speaker.

The unit has sensitivity adjustment which works great, as I managed to set mine so it wouldn't pick up any servo or motor noise, but picks up the voice absolutely fine. Here's a
link to the unit.

Hope this helps.

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So, we have off-the-shelf complete EL wire solution from Steve G.

Using the solution Richard R posted, if you connect multiple LEDs, they will all respond the same (brighter the louder the sound). You will need to know a little about electronics to determine whether to connect in parallel or series and how much voltage to supply and how big the resisters need to be on the LEDs, but a little research could get you there pretty easily.

I am pretty sure if you wire LEDs in series, with resistors between each one, when you connect that device to the first LEDs in the series, you will get exactly the effect in the linked video. (ie, the center LEDs would be closest to the power source, so they would turn on at low power when the others don't, and they would be bright when the others are just turning on).

The same could be done a single digital port on the EZ-B using a PWM control. To drive more than a couple of LEDs you would also need a TIP120 circuit and external power matched to the input of the LEDs (you could use a voltage regulator, resistors, or a combination. If you are supplying your EZ-B with 7.4 volts, you could probably use the power pin (not the signal pin) from your EZ-B to provide the voltage.

In the next few days I'll throw something together using 5 LEDs and 5 digital ports and an example script/project that will do the same function, but no additional circuits. Just EZ-B and as many digital ports as you have LEDs. So, super simple, but uses a lot of ports.

If you want to try yourself before I get to it, the concept will be that I will put a sound servo object in my project, but configure it to a virtual servo port.

I'll then create a script using WaitForChange and will use the value of the $SoundValue variable to determine which ports and how much PWM to supply every time it changes.

United Kingdom
What I would like to do in my next project is to connect a couple of EL wires directly to the EZ-B and control the light phasing from there.

I do have a question which may sound a little dumb or obvious. What voltage bulbs should be used to connect two LED's to one digital port with a 7.4v LiPo powering the EZ-B. I Suppose what I'm asking about is safty margins to comfortably run two LED's without under or over volting them.
The signal pin on the EZ-B can deliver 3.3 volts at 20 mA (I am getting the 20mA from other posts. It isn't on the datasheet, so it might be higher. I know it is not lower), so if you want direct control with no additional circuitry, you can use that to pick your LEDs (there is a wide variation in voltage and amperage on LEDs, so you will need to check their specs and do the math).

If you need more voltage or amperage, you can use a TIP120 transistor circuit to use the EZ-B signal pin to control but either the EZ-B power pin or external power to actually provide voltage to the LEDs.

I need to do some videos soon. On my ROLI, I have a superbright LED "headlight" mounted on one side of the camera, and a 5v laser diode on the other side. The LED is directly connected to a digital port, and I adjust the brightness with a PWM control.

The Laser worked, but was not bright enough at 3.3 volts, so I built a TIP120 and 5V regulator inline circuit so it is powered by the 7.4 v EZ-B input, but switched with a PWM control. I uses PWM instead of Digital On/Off because although 3.3 v was too weak to make a visible spot at any distance, 5v made a very bright spot, and since one of the primary uses for this is to play with the cat, I wanted to reduce the chance of accidently blinding her (or a person I guess), so I set the PWM to about 35% and it gives a decent spot without being too bright.

(note: if anyone wants a red laser diode, I got a pack of 10 for $6 through Amazon. http://www.amazon.com/gp/product/B00RABH0NM/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1 )

United Kingdom
Great. Thanks for the response Alan. That cleared things up a bit. What I'm looking to do is connect two LED's in series to one port to act as eyes, and blink at random intervals. I hope you do get around to doing a video or two on this. I'd be interested to see them.
@Steve, Im doing that too. But the LED wasn't very bright as it should be. Im hacking an omnibot.

I haven't set up the multiple LED's yet, but the project attached to the first post in this thread http://www.ez-robot.com/Community/Forum/Thread?threadId=7167 uses a script to monitor the sound servo's variable and vary the PWM going to an LED when the script containing speech is run.

The sound servo EZ-B required no configuration since I am just using its variable and not actually driving a servo.

Connect an LED to port D11, run the Sound LED script, and then run the Speech Test script. Adjust Sound servo settings (speed and scaling) and scripts (port used, speech spoken, etc) as needed.


I'll give that a try tonight.