hardware for pushing buttons

Question

Many times I want my computer to interface old hardware. Such as radio, light switch, etc. This mostly involves pushing pressing and moving various buttons and switches.

I don't want to buy new hardware I want my computer to interface the old hardware I already have.

I thought about it and reached to the conclusion that what I need is a general purpose button-pusher hardware.

I need a simple device I can interface by a computer and would be able to push most of the buttons we have in daily accessories, without damaging the button.

Is there any such accessory availible?

(migrated from superuser, where I got no satisfactory answers).

Answer 1

Are you completely opposed to making minor modifications to those old devices? If not, you can probably interface with them by means of placing relays in the circuits the buttons and switches control.

Answer 2

You could use a variety of actuation devices. First off is the humble solenoid - basically a coil-gun where the slug can't leave the coil. They can exert a lot of force, but can't be controlled in terms of speed and give a nice "whack" sound.

A servo with a rocker arm would work (mechanically more complex). Its capability of pushing buttons would be slower, but more controlled.

A stepper motor or a free-running servo could accomplish rotary dials.

A linear actuator (stepper motor on a screw-shaft) could accomplish sliding actions.

The most custom portion would be the mechanical interface. I suggest hunting around http://smallparts.com and http://mcmaster.com

You could probably find ready-made interface electronics (motor controllers over USB even) at Pololu: http://www.pololu.com/

Answer 3

Old thread but...

I'm considering something like this myself. Either with phidgets (phidgets.com) an actuator: 3541_0 Linear Actuator L12-50-100-06-R 1066_0 PhidgetAdvancedServo 1-Motor

or with Gadgeteer with a relay: http://channel9.msdn.com/coding4fun/blog/Shining-a-light-on-a-Windows-Phone-Net-Gadgeteer-Light-Switch

Both are a bit overkill for pushing a coffee brewer switch :D

Answer 4

This is an interesting problem. I haven't ever done anything like this, but I too have pondered actuators for physical components.

For button pushing, I would probably go with pneumatic (air-powered) actuators; you can easily control the amount of force and you can find them in a wide variety of sizes. Control would be done through solenoid-controlled valves, and all you need is a source of clean and dry compressed air, which is almost never an issue.

Switch flipping is more difficult. My first solution would be to have some kind of a mechanical converter to convert the linear motion of a pair of pneumatic actuators to more of a diagonal motion that switches use, but you'd quickly run into physical size issues. A tiny stepper motor with a similar rotary-to-linear interface over the switch would work and be smaller. Stepper motors would also work very well for controlling anything that had to be turned (tuning wheels, volume knobs, etc.)

There is a surplus place close to me that had a huge pile of these style of actuators. Now I want to go buy some and play. :-)

Answer 5

Using analogue switches across the actual switches, controlled by a computer or MCU, is a popular technique, and avoids messing about with mechanical actuators. The 74HC4066 is a typical device that can be used.

Answer 6

You can find many very cheap USB DIY projects that could be used to interface your old equipment here: http://www.obdev.at/products/vusb/prjhid.html.

Answer 7

Interface to Lego Mindstorms, build fake fingers with the rubber-tip part, have Mindstorms motor press the button. I did this once.

Alternatively, use a Microcontroller to interface to RC servos.

Answer 8

Interesting problem. I am assuming that the types of buttons/switches you would want to push/move in will have a variety of 'resistances'. By resistances I mean that you may need a small nudge for one button but a forceful whack for another. Also, this may ask for a configurable position (horizontal + vertical) of your actuator that does the actual work of pushing or moving on the accessory.

Though, I've personally never tried this, I think a mini servo motor that gives a fine grained degree of control in its movement can be used (similar to Andrew's answer in this thread). The servo motor in turn can be connected to your actuator through a spring loaded trigger mechanism. The spring tension will vary as per the 'resistance' of the button or switch. This whole mechanism in turn should sit on a platform that itself is movable horizontally and vertically (a set of couple of mini servo motors again).

Admittedly, my option looks elaborate but I feel if it is designed well, it has endless applicability on all kinds of accessories and may be cheaper than custom devices. The platform can be omitted initially to make it even cheaper.

Answer 9

For some applications, this might be an easier solution, a relay controlling mains power.

http://www.adafruit.com/index.php?main_page=product_info&cPath=44&products_id=268