[Lab] Controlling Light with a Ventilator

Mon Mar 25 01:13:17 EDT 2013

Hi Chris,

Connecting the Pi to a projector can be done with an HDMI cable or
Composite cable as the Pi outputs both (but HDMI would be better!).

The Pi comes with nothing more then a circuit board so you will need the
following:

1. A video cable (hdmi or composite)

2. A power supply which can be any USB wall charger that can supply 1amp -
an iphone charger works well.

3. Keyboard and mouse (just for setup you wont need them while its running)

4. A SD Memory card - go for one that is 4Gb or more, class 10 (although I
use a class 6 just fine) and is from a well known company like Sandisk.

5. Case is optional :) Some people just poke holes in the box that it comes
in, I made mine on the laser cutter at M70 - you can see it in the youtube
video sitting beside the monitor.

6. The sensor you listed has an analog output which the Pi can't read so
you will need an analog to digital converter with it. Last week I ordered a
MCP3008 ($4) which is a 10-Bit ADC for the upcoming workshop. I will let
you know if I get it to work.

Have you tried back lighting the canvas yet? Even just a flash light would
probably show you if the light will come through.

Cheers!
Kirk
On Sun, Mar 24, 2013 at 4:05 PM, The Big Plan - Chris B
<tbp at ghostwise.com>wrote:

>
> Hi Modlabbers (and especially Kirk, Roman and Henri in this message)!
>
> Thanks so much Kirk for going ahead and programming a RaspPi dimming
> function for the projector.
>
> I think the projector is probably the best way to control the lighting
> versus investing in LED lighting. How would I
> connect the RaspPi to the projector?
>
> From all the suggestions I've received on the list, I'd like to use these
> two items to control the lighting via the ventilator:
>
> A pressure sensor <
> http://www.digikey.com/product-detail/en/MPVZ5010GW7U/MPVZ5010GW7U-ND/1168379
> >
> Raspberry Pi
>
> I've never used a RaspPI so I don't know would I need for it. What kind of
> cables, enclosure, PSU does it need?
> If the order requirements could be spelt out to me I'd appreciate it. I
> would then go ahead and order the equipment
> needed to do this.
>
> Last night a friend suggested a possible problem: If I backlight the
> painting, the squares on the front may end
> up simply looking dark. Would it be smarter to project onto the front of
> the painting? I was hoping the light source
> wouldn't be so apparent but if the visual doesn't work with backlighting,
> I may have to.  It is a pretty thin layer
> of acrylic paint so the light may glow through it.
>
> I'm also trying to figure out how to suspend the canvas. It's not
> stretched on a frame. I'd like to keep it loose like a
> sail with it bulging a little forward towards the viewers. My friend
> suggested using a fan on low to keep it bulging
> forward. I wonder if the same effect could be done through tension.
>
> As a BIG aside, If I had an iPhone, iPad and possibly a computer all
> working together to create music, what would
> I need to make the painting into a giant visualizer for the music? :D I
> suppose video of a visualizer of some sort
> would have to be projected onto the canvas.
>
> Thanks again for all your interest! I hope I can put together version 1.0
> of the painting installation in May / June.
>
> Chris
>
>
> On 24-Mar-13, at 12:33 AM, Kirk Sutherland wrote:
>
> Hi Chris,
>
> I had a chance to try out the visual aspect of what you are describing on
> a Raspberry Pi and it was pleasantly easy! The code was written in Python
> on a stock install of the operating system 'Rasbian', I simply turned on
> the Pi, wrote the code and ran it - didn't have to install anything else!
>
> The code displays 5 'breaths', each cycle lasts 2 seconds going from black
> to full white. If you had the Pi connected to a projector as your 'light' I
> believe this could work nicely. There are some artifacts as the colour
> changes because I am simply refreshing the screen really fast, but if you
> have you canvas to act as a diffuser I don't think you would see them.
>
> https://www.youtube.com/watch?v=QjOoXHBC5Ic<https://www.youtube.com/watch?v=QjOoXHBC5Ic&feature=youtube_gdata_player>
>
> Have you picked your sensor yet?
>
> Cheers!
>
> Kirk
> On Mar 22, 2013 9:03 AM, "Kirk Sutherland" <kirk.sutherland at gmail.com>
> wrote:
>
>> I second the raspberry pi as a projector controller! Its cheap,
>> projectors are bright (and can be borrowed!), and I don't think the code
>> would be that hard. You will have to use some external controller with the
>> Pi if the sensor is analog as the pi has only digital io. I could try out
>> some simple code tonight to see if the video part is possible without
>> getting into opengl code :)
>> Cheers!
>> Kirk
>> On Mar 21, 2013 9:21 PM, "Henri Kuschkowitz" <henri.kuschkowitz at gmail.com>
>> wrote:
>>
>>> Hey Chris,
>>>
>>> I know you already received tons of ideas, but i was thinking about a
>>> mini fan put somewhere between parts of the tube (maybe after the bacteria
>>> filter) and you then just measure the speed of it to determine the power
>>> for your lights?
>>>
>>> For the question regarding lights, there are hundreds of controllable
>>> led strips out there that could suit your needs. or maybe EL solutions
>>> (though it would cost you more i think) like this:
>>> https://www.sparkfun.com/products/10800
>>>
>>> Also, you can dim a projector simply by projecting grey scale images…
>>> which means a raspberry pi connected to the sensor could be a neat solution.
>>>
>>> Just my 2 cents.
>>>
>>>
>>> Cheers and good luck,
>>> Henri
>>>
>>> On 2013-03-21, at 5:46 PM, The Big Plan - Chris B wrote:
>>>
>>>
>>> Hi Modlabbers,
>>>
>>> Thanks for all the interest in my art installation!
>>>
>>> So far it looks like the pressure sensor idea is the one I'm leaning
>>> towards. Having a microphone detect the ventilator breaths sounds more
>>> finicky to me.
>>>
>>> Still trying to figure out how to back light the canvas. Would a
>>> projector work instead of using LED lighting? Can a projector
>>> be connected to the pressure sensor set up to do the variable dimming?
>>>
>>> Club SAW has 3 projectors available:
>>>
>>> Panasonic PTAX200U HD Video Projector
>>> 16mm Projector
>>> 35mm Projector
>>>
>>> As for a timeline / schedule. If I could do this in May / June that
>>> would be great but it may be more realistic to wait until September.
>>>
>>> Here's a photo of the painting below. It's about 7 by 11 feet:
>>>
>>> Thanks,
>>> Chris
>>>
>>> <2012-11-12 14.51.55.jpg>
>>>
>>>
>>>
>>>
>>>
>>> On 15-Mar-13, at 8:41 AM, Michael Sepa wrote:
>>>
>>> Chris,
>>>
>>>
>>> The clarification of the project really helps out.  I looked up the
>>> manual for the Puritan Bennet LP10 (
>>> http://www.meql.com/Manuals/Puritan-Bennett-LP6-Plus-and-10-Ops-Manual.pdf)
>>> in the hope that there would be a simple electronic monitor connector on
>>> the back that you could hook into, but no such luck.  There are pressure
>>> alarms that can be set and a remote alarm connection on the back of the
>>> machine, but you'll get audible alarms off the machine at the same time.
>>>  Not what you intend.
>>>
>>>
>>> One approach would be to do the following:
>>>
>>>
>>> 1. Lights start off, no ventilator pressure
>>>
>>> 2. Ventilator turns on, a microphone beside the patient air tube senses
>>> flow
>>>
>>> 3. Arduino detects change from microphone
>>>
>>> 4. Arudino uses pulse width modulation[2] to brighten an LED array from
>>> off to full on in 1.5s, and holds
>>>
>>> 5. Ventilator turns off
>>>
>>> 6. Microphone detects stop of flow from patient air tube
>>>
>>> 7. Arduino uses pulse width modulation to dim an LED array from current
>>> level to off in 1.5s and holds
>>>
>>>
>>> [1] pulse width modulation is just a fancy way to say turn on/off the
>>> LED array fast enough to control brightness.  This is built into the
>>> Arduino system, so it's very easy.
>>>
>>>
>>> Connecting to and dimming an LED array with an Arduino is well
>>> understood.  No issues there.
>>>
>>>
>>> The microphone will require an amp chip to get it producing a signal the
>>> Arduino can easily read.  If we can find a pre-made microphone and amp,
>>> then it will be all so much easier.
>>>
>>>
>>> The programming of the system would be straight forward.  Certainly less
>>> than a day of effort.
>>>
>>>
>>> The system would work well if the room was reasonably quiet.  If there
>>> was other noise it might trigger the microphone causing premature light
>>> adjustment.  A better approach would be to use a pressure sensor.  I
>>> checked ebay and see several pressure sensors available, all use I2C
>>> interfaces.  That would take a bit more programming effort, but certainly
>>> less than a day or two.
>>>
>>>
>>> If you go with a pressure sensor, we'd need to makes sure the sensor has
>>> the right range to sense the ventilator pressure.  That I couldn't get from
>>> the quick ebay search because they don't usually publish specs with sale
>>> items.  I'm confident  we could find an appropriate one on ebay, spark fun,
>>> or somewhere else.
>>>
>>>
>>> As for your budget, I'd think you should have no issues buying all the
>>> tech plus paying someone a small honorarium for helping you program it all.
>>>
>>>
>>> My big question would be what's your schedule?
>>>
>>>
>>> -Michael Sepa
>>>
>>>
>>>
>>> Date: Thu, 14 Mar 2013 17:49:08 -0400
>>> From: The Big Plan - Chris B <tbp at ghostwise.com>
>>> To: lab at artengine.ca
>>> Subject: Re: [Lab] Controlling Light with Sound
>>> Message-ID: <F3148EB9-8831-464E-92AA-2144AB15E72B at ghostwise.com>
>>> Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes
>>>
>>> Hi everyone,
>>> Thanks for the awesome replies so far. I think I should clarify my
>>> intentions:
>>> My plan is to suspend a loose canvas that is approximately 7 by 11
>>> feet on an angle from the ceiling.
>>> I would like to put lighting behind it (I don't know what lighting to
>>> use or whether it
>>> should be a set of lights). The rest of the room will be dark.
>>> A ventilator (Puritan Bennett LP10) will be on the floor. Every breath
>>> of the ventilator
>>> should cause the lights to turn on in a gradual way and then dim dark
>>> as the breath
>>> ends. Each breath should take about 1.2-1.5 seconds.
>>> I like the idea of an Arduino or Raspberry Pi controlling the lighting.
>>> It sounds like I will also need a mic by the ventilator.
>>> Finally, I have zero programming experience or overall technical
>>> experience to do this. I'm the artist
>>> with a vision. I would appreciate assistance from anyone interested in
>>> this project.
>>> It would be great if it could be done on a $250-500 budget.
>>> Thanks in advance,
>>> Chris
>>> On 14-Mar-13, at 4:11 PM, The Big Plan - Chris B wrote:
>>>
>>>
>>> Hi!
>>>
>>>
>>> Looking for some advice for an art installation. I'd like to have a
>>>
>>> light or set of lights respond to an auditory
>>>
>>> input. I'd like the lights to turn on in time with the sound of a
>>>
>>> ventilator (a medical one). So when the ventilator is
>>>
>>> not doing a breath, the lights would be off, but then when the
>>>
>>> ventilator starts doing a breath they would
>>>
>>> turn on for the duration of the breath. I'd like the lights to light
>>>
>>> up and dim gradually, not just on an off.
>>>
>>>
>>> What's a simple or best way to do this?
>>>
>>>
>>> Thanks!
>>>
>>>
>>> Chris
>>>
>>>
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