Best simple way to move something 6 inches remotely
April 6, 2013 9:13 AM Subscribe
Help me move a microphone which is locked in a box.
I'm building a box to isolate my guitar speaker, so I can record without disturbing the rest of the house. The box will have a speaker inside with a microphone pointing at it. I would really like to find a way to move the microphone from side to side about 6 inches or so. When you record guitar amps, moving the microphone as much as half an inch makes a significant change in the tone, and since the mics will be sealed inside a box in a different room, moving them by hand is going to be really difficult.
So, I'm looking for some way to remotely move the mics from side to side, no more than 6 inches. It needs to be able to be remote controlled (although not wireless, I'll already have other wires coming out of the box and running to where I'll be sitting). Ideally it would be detailed enough to move very short distances (1/4-1/2 inch), rather than just jerking from one side to the other quickly. In a perfect world, it could be set to actually hit specific spots, so I could always recall back to certain positions, although this is not required.
I have some electronics experience (I can solder and whatnot), plenty of tools, and some time to work on this. What I don't have is a huge budget or programming skills. I'd love something as simple as possible, I'm not interested in something that requires a computer to work.
The mics being moved are less than a pound each, so the system doesn't need to be very powerful.
So, does anyone have an idea of how to do this?
I'm building a box to isolate my guitar speaker, so I can record without disturbing the rest of the house. The box will have a speaker inside with a microphone pointing at it. I would really like to find a way to move the microphone from side to side about 6 inches or so. When you record guitar amps, moving the microphone as much as half an inch makes a significant change in the tone, and since the mics will be sealed inside a box in a different room, moving them by hand is going to be really difficult.
So, I'm looking for some way to remotely move the mics from side to side, no more than 6 inches. It needs to be able to be remote controlled (although not wireless, I'll already have other wires coming out of the box and running to where I'll be sitting). Ideally it would be detailed enough to move very short distances (1/4-1/2 inch), rather than just jerking from one side to the other quickly. In a perfect world, it could be set to actually hit specific spots, so I could always recall back to certain positions, although this is not required.
I have some electronics experience (I can solder and whatnot), plenty of tools, and some time to work on this. What I don't have is a huge budget or programming skills. I'd love something as simple as possible, I'm not interested in something that requires a computer to work.
The mics being moved are less than a pound each, so the system doesn't need to be very powerful.
So, does anyone have an idea of how to do this?
You want a stepper motor with a belt attached to the shaft and run across the box with the mic mounted on the belt. Then you can turn the motor and it will pull the mic back and forth across the box on the belt. You just need to find or build an appropriate controller for the stepper motor.
posted by tylerkaraszewski at 9:21 AM on April 6, 2013
posted by tylerkaraszewski at 9:21 AM on April 6, 2013
radio controlled airplane positioners are cheap, but you are looking for a position loop. antenna motor and controller from an old tv installation would work, too. moves and stops. heavy loads. slow. should be close to free, if you can find one.
strings and pulleys, too. if it's this simple, why get complicated?
posted by FauxScot at 9:22 AM on April 6, 2013
strings and pulleys, too. if it's this simple, why get complicated?
posted by FauxScot at 9:22 AM on April 6, 2013
I'd take a large cheap drill press vise and replace the handle with a small gear-head DC motor. Movement is controlled with a simple momentary SPDT switch. Repeatability could be handled with a series of limit switches spaced at whatever resolution you wanted along with an override.
posted by Mitheral at 9:26 AM on April 6, 2013
posted by Mitheral at 9:26 AM on April 6, 2013
why can't the floor board be wider than the box? just saw two holes into it and have the floor board stick out. you just pull it left and right and the mic moves. have a separate area for the speaker to stand on so that it doesn't move as well.
posted by krautland at 10:29 AM on April 6, 2013 [1 favorite]
posted by krautland at 10:29 AM on April 6, 2013 [1 favorite]
Not an answer but a request for more information: does the microphone have to translate or can it move through an arc? Does the mechanism have to be silent or can it make noise between positions?
posted by jet_silver at 11:10 AM on April 6, 2013
posted by jet_silver at 11:10 AM on April 6, 2013
If you're going the electronics route, an RC servo is what you want. (They're a motor, gearhead, position feedback pot, and controller in a small box, and they're cheap.)
But it seems to me a manually operated push-rod, maybe with known positions marked on it in pencil, would do the trick and is easier than anything electronic.
posted by hattifattener at 11:11 AM on April 6, 2013
But it seems to me a manually operated push-rod, maybe with known positions marked on it in pencil, would do the trick and is easier than anything electronic.
posted by hattifattener at 11:11 AM on April 6, 2013
So, uh, do you know that your speaker is going to sound super weird once you seal it in a box? Beware.
posted by ryanrs at 11:26 AM on April 6, 2013
posted by ryanrs at 11:26 AM on April 6, 2013
Response by poster: I am fully aware of the acoustic issues with an isolation box.
The box will be in a separate room, and I want to be able to adjust the mic position while listening in the studio, so it needs to be something remotely operated. The box will be completely sealed, so no rods or strings can be used. Ideally the mic will move in a straight line side to side. The mechanism can make noise, it won't be moving while recording.
posted by markblasco at 12:27 PM on April 6, 2013
The box will be in a separate room, and I want to be able to adjust the mic position while listening in the studio, so it needs to be something remotely operated. The box will be completely sealed, so no rods or strings can be used. Ideally the mic will move in a straight line side to side. The mechanism can make noise, it won't be moving while recording.
posted by markblasco at 12:27 PM on April 6, 2013
In that case: a servo and a simple 555-based servo controller sounds easiest. (There are a bunch of different 555-based circuits to do that job on the net; I'm not sure what their pluses and minuses are, but the one I linked is one of the simplest.) Connect the servo to a lever that slides the mic back and forth on a rail or wheels or something.
Servos do make little whiny gear noises when moving but they're quiet when stopped. You could even power the whole thing off when you're not adjusting the position, if you want.
posted by hattifattener at 12:41 PM on April 6, 2013
Servos do make little whiny gear noises when moving but they're quiet when stopped. You could even power the whole thing off when you're not adjusting the position, if you want.
posted by hattifattener at 12:41 PM on April 6, 2013
I know you said that you don't want a computer involved but it really seems to me like by far the easiest and most reliable way to do this would be to use an old junked printer if you can figure out how to send the commands to directly move the print head back and forth.
I mean, the whole mechanism you need and the means to precisely remotely control it is already engineered, tested, and manufactured in a QCed process for you - why start over from scratch?
posted by XMLicious at 12:47 PM on April 6, 2013
I mean, the whole mechanism you need and the means to precisely remotely control it is already engineered, tested, and manufactured in a QCed process for you - why start over from scratch?
posted by XMLicious at 12:47 PM on April 6, 2013
Response by poster: I understand the idea behind using a junk printer, but that sounds 10 times more difficult than a servo or other mechanical option. I'm not interested in using a computer for this, I want something simple with either a dial or switch or joystick or something similar to operate. If it requires programming than it's probably not going to happen.
posted by markblasco at 1:28 PM on April 6, 2013
posted by markblasco at 1:28 PM on April 6, 2013
The use of servos and steppers seems a bit like overkill.
A cheap motor hooked to a suitable drive mechanism plus some microswitches and a relay or two seems like it would be enogh.
For the mechanism, a screw drive would work. I know they make small ones. Another option is a carriage on rails plus a toothed belt. Look at OpenBeam, MakerBeam and similar extruded aluminum systems, I'm pretty sure someone made a carrier.
The control circuit I am imagining would have two momentary switches connected to relays. Clicking a switch would close the relay. The closed relay would provide current to keep the relay closed and cause the motor to spin in one direction. Along the travel of the carriage, you'd have microswitches. When the carriage triggered the switch it would momentarily cut power to the whole circuit, causing the relay to open, stopping the motor. To move to the next position, you'd pulse the appropriate control switch again.
On the other hand, if you want more precise placement than a handfull of stops, a servo or stepper would probably be the way to go. Salvaging the motor and the mechanism from an old printer or scanner could be a great source. At that point, it might be worth throwing a microcontroller, like an arduino, into the mix to handle precision placement and measuring of placement.
I'd suggest going to the Sparkfun, Arduino.cc and/or HackADay forums and asking for suggestions. When you are done, HackADay might be interested in a writeup of your build.
posted by Good Brain at 1:34 PM on April 6, 2013
A cheap motor hooked to a suitable drive mechanism plus some microswitches and a relay or two seems like it would be enogh.
For the mechanism, a screw drive would work. I know they make small ones. Another option is a carriage on rails plus a toothed belt. Look at OpenBeam, MakerBeam and similar extruded aluminum systems, I'm pretty sure someone made a carrier.
The control circuit I am imagining would have two momentary switches connected to relays. Clicking a switch would close the relay. The closed relay would provide current to keep the relay closed and cause the motor to spin in one direction. Along the travel of the carriage, you'd have microswitches. When the carriage triggered the switch it would momentarily cut power to the whole circuit, causing the relay to open, stopping the motor. To move to the next position, you'd pulse the appropriate control switch again.
On the other hand, if you want more precise placement than a handfull of stops, a servo or stepper would probably be the way to go. Salvaging the motor and the mechanism from an old printer or scanner could be a great source. At that point, it might be worth throwing a microcontroller, like an arduino, into the mix to handle precision placement and measuring of placement.
I'd suggest going to the Sparkfun, Arduino.cc and/or HackADay forums and asking for suggestions. When you are done, HackADay might be interested in a writeup of your build.
posted by Good Brain at 1:34 PM on April 6, 2013
I understand the idea behind using a junk printer, but that sounds 10 times more difficult than a servo or other mechanical option. I'm not interested in using a computer for this, I want something simple with either a dial or switch or joystick or something similar to operate. If it requires programming than it's probably not going to happen.
Are you referring to any use of a computer at all as programming? I'm imagining something like typing a number in and hitting enter, to just send control codes with the desired coordinates to the printer.
Figuring out how to rig up a dial or joystick to a stepper motor controller and various switches and devising a way to allow that setup to store and recall particular positions—which as I said would appear to already be done for you in a printer that can simply be told "go to coordinate x"—seems a heck of alot more complicated and much more like programming to me, but to each his own.
posted by XMLicious at 2:39 PM on April 6, 2013
FWIW, one of my favorite linear sliding mechanisms is a ball-bearing type kitchen drawer slide. Home Depot or Lowes has them and they are cheap. you can mount them flat as opposed to vertically and they are cheap. they are also really low friction and you can get them in 30" lengths or a lot shorter.
if you rig it with a very simple motor to a loop of cable or fishing line or string you can get a large mechanical advantage. wire the motor with a momentary contact switch and a direction switch (radio shack double pole, double throw type switch; very simple) and power it with either a battery or a wall wart. this will let you select a direction and "jog" the positioner. for the precision you require, this seems about the minimum. using a normally open momentary contact switch will give you full instantaneous torque so bumping it fast will be the trick for short movements. if you wanna get flashy, you can use some roller limit switches (also radio shack items) to detect end-of-travel conditions. you should use something for that and i don't know of anything simpler. this is a $25 project (in parts). if you have any questions, memail and i'll send you some radio shack part numbers.
posted by FauxScot at 3:38 PM on April 6, 2013
if you rig it with a very simple motor to a loop of cable or fishing line or string you can get a large mechanical advantage. wire the motor with a momentary contact switch and a direction switch (radio shack double pole, double throw type switch; very simple) and power it with either a battery or a wall wart. this will let you select a direction and "jog" the positioner. for the precision you require, this seems about the minimum. using a normally open momentary contact switch will give you full instantaneous torque so bumping it fast will be the trick for short movements. if you wanna get flashy, you can use some roller limit switches (also radio shack items) to detect end-of-travel conditions. you should use something for that and i don't know of anything simpler. this is a $25 project (in parts). if you have any questions, memail and i'll send you some radio shack part numbers.
posted by FauxScot at 3:38 PM on April 6, 2013
For the mechanism, a screw drive would work. I know they make small ones. Another option is a carriage on rails plus a toothed belt. Look at OpenBeam, MakerBeam and similar extruded aluminum systems, I'm pretty sure someone made a carrier.
I like this better than my idea. A screw drive + a reversible motor would be fine.
(In fact, I just threw away something that had all the parts you'd need for this! Sorry. Check ebay for a broken Lexmark 4060-hcf or 4061-hcf. It has a 24v motor, power supply, pulleys, screw drive and a carriage thing that rides on the screw drive, with about 12 inches of travel. It's a high capacity feeder for a line of Lexmark printers, and uses this mechanism to raise and lower a tray of 2000 sheets of paper. It wouldn't take much at all to convert this to your project. Just tear out all the electronics and run a cable with a three way toggle switch. Normally off, rock to the right or left to spin the motor one way or the other. Run it on 12v for finer control.)
Another option could be something like this contraption. If you hook a motor to the rotating shaft and choose the diameter correctly, you might not have to worry about gear reductions and whatnot. As the motor turns, it winds up more line on one side, which causes the carrier to slide to one side or the other. Not particularly elegant, but easy to construct. No complicated parts or machining necessary.
On preview: you could modify the top thing to use FauxScot's drawer slide, which would make it even simpler. No need to find a rod and a carrier that will slide on it.
For speed control, you can use potentiometer in series with the power to fine tune the voltage going to the motor. Standard DC hobby motors can handle variable voltage enough for the application.
Also, converting an old dot matrix printer to this effort probably wouldn't be that hard. Or even an old typewriter would be better- just find one that you can wire up the spacebar and backspace keys with separate switches and off you go.
Final off the wall suggestion: look at the home center for electric HVAC duct dampers. Those should work the way you want them (set position and it stays) and mounting it to a drawer slide would be relatively simple.
Good luck!
PS- Version 2.0 should include XY movement. I'm helpful!
posted by gjc at 4:07 PM on April 6, 2013 [1 favorite]
I like this better than my idea. A screw drive + a reversible motor would be fine.
(In fact, I just threw away something that had all the parts you'd need for this! Sorry. Check ebay for a broken Lexmark 4060-hcf or 4061-hcf. It has a 24v motor, power supply, pulleys, screw drive and a carriage thing that rides on the screw drive, with about 12 inches of travel. It's a high capacity feeder for a line of Lexmark printers, and uses this mechanism to raise and lower a tray of 2000 sheets of paper. It wouldn't take much at all to convert this to your project. Just tear out all the electronics and run a cable with a three way toggle switch. Normally off, rock to the right or left to spin the motor one way or the other. Run it on 12v for finer control.)
Another option could be something like this contraption. If you hook a motor to the rotating shaft and choose the diameter correctly, you might not have to worry about gear reductions and whatnot. As the motor turns, it winds up more line on one side, which causes the carrier to slide to one side or the other. Not particularly elegant, but easy to construct. No complicated parts or machining necessary.
On preview: you could modify the top thing to use FauxScot's drawer slide, which would make it even simpler. No need to find a rod and a carrier that will slide on it.
For speed control, you can use potentiometer in series with the power to fine tune the voltage going to the motor. Standard DC hobby motors can handle variable voltage enough for the application.
Also, converting an old dot matrix printer to this effort probably wouldn't be that hard. Or even an old typewriter would be better- just find one that you can wire up the spacebar and backspace keys with separate switches and off you go.
Final off the wall suggestion: look at the home center for electric HVAC duct dampers. Those should work the way you want them (set position and it stays) and mounting it to a drawer slide would be relatively simple.
Good luck!
PS- Version 2.0 should include XY movement. I'm helpful!
posted by gjc at 4:07 PM on April 6, 2013 [1 favorite]
Your problem with most of the suggestions is moving that 1/4 inch, and repeatability. How about using Lego Mindstorms? If you need a consultant, there's plenty of 5th graders who can help.
posted by Sophont at 5:30 PM on April 6, 2013
posted by Sophont at 5:30 PM on April 6, 2013
There's also a camera panbase. If you add a cheap wired camera, and some markings, you could get accurate repeatability.
posted by Sophont at 5:50 PM on April 6, 2013
posted by Sophont at 5:50 PM on April 6, 2013
A remote control camera pan head might be the cheapest option that is close to plug and play. The one linked to has an IR sensor extension which could be easily placed outside the box.
posted by jmsta at 4:56 AM on April 7, 2013 [1 favorite]
posted by jmsta at 4:56 AM on April 7, 2013 [1 favorite]
The remote control pan head will also give you both X & Y Axis control.
posted by jmsta at 4:58 AM on April 7, 2013
posted by jmsta at 4:58 AM on April 7, 2013
does it need to move 'side-to-side' as well as 'back-and-forth'?
b/c if not, this is super easy. remote controlled toy car (make sure it's 'radio controlled'...IR remotes require line-of-sight and won't work through a box), with 2 small strips of wood (or anything, really) you can make a track to confine it to just back and forth
they also sell wired remote-control cars (you can sometimes find them really cheap at the drugstore) and they often have 'forward' and 'back' as their ONLY control...all you would need to do is extend the wire...
this would probably work best with a truck so you have a built-in place to put the mic...
if it moves too fast (it probably will) you can reduce the number of batteries (rewiring the battery case=easy) or putting in a resistor of some type before the motor to slow it down
posted by sexyrobot at 12:05 PM on April 7, 2013
b/c if not, this is super easy. remote controlled toy car (make sure it's 'radio controlled'...IR remotes require line-of-sight and won't work through a box), with 2 small strips of wood (or anything, really) you can make a track to confine it to just back and forth
they also sell wired remote-control cars (you can sometimes find them really cheap at the drugstore) and they often have 'forward' and 'back' as their ONLY control...all you would need to do is extend the wire...
this would probably work best with a truck so you have a built-in place to put the mic...
if it moves too fast (it probably will) you can reduce the number of batteries (rewiring the battery case=easy) or putting in a resistor of some type before the motor to slow it down
posted by sexyrobot at 12:05 PM on April 7, 2013
Hobby shops that carry Tamiya mechanisms like those shown here might be an easy way to do what you have in mind.
posted by jet_silver at 6:37 PM on April 7, 2013
posted by jet_silver at 6:37 PM on April 7, 2013
Response by poster: Thanks for the ideas everyone. gjc, that "contraption" you linked to is for exactly what I'm trying to do, but I'm trying to make it much more elegant and less hacked or DIY. Ideally there would be some electronics kit somewhere that has a control for a little hydrolic press that can move 6 inches (heck, even 3 inches would be great).
Mitheral, that drill press idea looks like it might be the way I'd go, but does anyone have a suggestion for how to hook the motor to it so that it would actually work. It looks like I'd have to mount the motor to the handle, and the motor would move left to right along with the press. How would I get the motor itself to not spin, and to move along side it reliably.
I'm really not looking for something super complicated, or that's going to require 10 hours of hacking to work. If it's very complicated, takes up a lot of space, or is going to look like it's thrown together than I just won't do it. There are a million other DIY projects that I've got on my list, I was hoping this would be an easy one where I could buy a kit and spend an hour putting it together.
posted by markblasco at 12:00 PM on April 8, 2013
Mitheral, that drill press idea looks like it might be the way I'd go, but does anyone have a suggestion for how to hook the motor to it so that it would actually work. It looks like I'd have to mount the motor to the handle, and the motor would move left to right along with the press. How would I get the motor itself to not spin, and to move along side it reliably.
I'm really not looking for something super complicated, or that's going to require 10 hours of hacking to work. If it's very complicated, takes up a lot of space, or is going to look like it's thrown together than I just won't do it. There are a million other DIY projects that I've got on my list, I was hoping this would be an easy one where I could buy a kit and spend an hour putting it together.
posted by markblasco at 12:00 PM on April 8, 2013
Response by poster: Oh, and to clear up any possible confusion, it doesn't need to turn, it needs to slide side to side. The microphone will be at a 90 degree angle to the front of the speaker, and I want to move it from the center of the speaker out towards the edge. It doesn't need to do anything but slide from side to side. Up and down or tilting aren't going to ever get used.
posted by markblasco at 12:03 PM on April 8, 2013
posted by markblasco at 12:03 PM on April 8, 2013
I'd actually saw off the handle (or remove the pin depending on how it was attached) and just couple the motor directly to the shaft bracing the motor against the base. Unlike a bench vise the shaft doesn't move laterally when you turn the handle. Only the centre jaw is unfixed (the one between the handle and the outer jaw) and only it moves laterally when you turn the handle.
posted by Mitheral at 2:17 PM on April 8, 2013
posted by Mitheral at 2:17 PM on April 8, 2013
You know what? The mention of Lego reminds me that I had some rack and pinion lego parts when I was a kid, as well as motors and universal joints and whatnot. I'll bet you can find a kit that does exactly what you want. Something like this.
posted by gjc at 4:08 PM on April 8, 2013
posted by gjc at 4:08 PM on April 8, 2013
Response by poster: gjc, that is exactly the kind of thing I'm looking for, just with metal parts instead of lego, and a motor that moves really slowly. I'll have to keep my eyes open for something similar.
posted by markblasco at 9:26 PM on April 8, 2013
posted by markblasco at 9:26 PM on April 8, 2013
Response by poster: For people who come to this later, this so far looks like the best option (or at least a diy version). http://www.youtube.com/watch?v=Q_e-4cXfaMI
A linear actuator will move in one direction back and forth a small distance at slow speeds. I think if I find a cheap enough one of these, I can make something work without too much trouble. Thinking about it a little more, I could even make it move up and down, and just reposition a few things, and that should work out OK.
posted by markblasco at 4:49 PM on April 9, 2013
A linear actuator will move in one direction back and forth a small distance at slow speeds. I think if I find a cheap enough one of these, I can make something work without too much trouble. Thinking about it a little more, I could even make it move up and down, and just reposition a few things, and that should work out OK.
posted by markblasco at 4:49 PM on April 9, 2013
This thread is closed to new comments.
- Setting up the mechanicals to turn "steering" into "moving mike"
- Making sure the receiver is powered
For power, you could probably put an A/C power strip in the box to plug the amp into, and use a wall-wart to power the R/C receiver.(I know you don't need wireless, but R/C stuff is cheap and ubiquitous, and pretty easy to use.)
posted by spacewrench at 9:19 AM on April 6, 2013