Piano Stairs (Musical Stairs) Part 1 - Planning and feasibility

I have used the FlexiForce sensor before and it works ok. To make it work best, I had to create a disc that transferred the force from the plate to the sensor itself. Basically, I just had to increase the pressure over the sensor instead of just placing the sensor under the plate (the stair steps in your case). I am not sure you could just slide one of these under the laminate and have it work right away. I think you could create a relatively thin disc (1/16th in) that concentrated the force from the step onto the sensor and slide that under the laminate and have it work. The obvious problem would be the thickness of the disc would cause the laminate to not sit level.

I don't think PIR is the way to go as you would probably end up triggering it from several stairs as it has a wide sensing volume.

I would lean toward an IR pair mounted on the easy to access side of the stairs. This setup should be able to detect when an object (like a foot) is closer than the wall on the other side of the stair. They are pretty cheap too.

This link might help with the multiple tones at the same time with the Arduino.

Although, it might be faster and cheaper to just hack a Mini Keyboard instead of trying to get all of that working.

Arduino and Pi would be redundant.  You could use the Pi and it's IO to trigger it, or use the Arduino with a WAV or MP3 shield. I don't know why you'd want both.

This is awesome and fast feedback Kelly and Cole!

The only thing I don't like about the flexiforce is the cost($17 x 12 steps) and unknown life cycle of it having parts that wear.

I also thought about just using a keyboard directly but I want to us this as an opportunity to learn how to use the ardunio and or rPI. Also in the future depending on how well this works I might want to have a light on each stair that lights up when the sensor is triggered.

I really like your advice regarding the IR pair mounted on the easy access side of the stairs and I'm going to order an arduino, mp3 shield and 1 IR sensor to test.

I thought I needed a Pi to play out the mp3 with the arduino. I didn't know I could get a MP3 shield for the arduino. Thanks for the info.

Which do you think would be better for this project a Pi or arduino?

I will need to read 12 of the IR sensors.

Cool idea

I remember something similar in a night club mannnnny years ago, and it worked great....except when everyone stood on the stairs.

You might want to look at capacitive sensing.

You basically stick a foil on the underside of the stair treads.

http://playground.arduino.cc//Main/CapacitiveSensor?from=Main.CapSense

I believe there are also some dedicated chips, that might be able to help as well.

At least if you get sick of it, you can remove it with no damage.

Mark

Hi.  Do you like the auditory effects of the saw tooth wave?  I stumbled across an analog circuit that generates a saw tooth output using a schottky diode.  I am wondering if a VariCap Diode could be used in the circuit in lieu of a regular capacitor.  My idea is to have the arduino set the capacitance (tone control = f of note)  with one digital output pin ( if PWM cannot control the VariCap input then a resistor ladder might have to be used ) and turn the note on/off with another another digital output pin.  I will put a circuit diagram if needed, but it consists of  the Cap and Schockley in parallel up from ground, output tapped off at top of cap and a series resistor to set the max. current.       Output feeds Op-amp - Low Pass filter  - Op-amp - Speaker  ??

   _/|/|/|/|/|/|/|/|_

The triangle wave is much more pleasant to the ear.  It can be generated with an additional resistor in series with the Schockley diode.  Resistor2 and S.diode in series will then be in parallel with the Cap/VariCap.

__/\/\/\/\/\/\/\/\__

Looks like VariCaps are VHF devices and not AF devices.  Maybe someone smarter than I can figure out how to extract the audio freq. differential with the application of a FM detector or something else. 

Lots of other ways to gen a triangle wave especially using op-amps.

use of pressure sensor will not be useful. but optical device will give good result.

The sensing indeed will be the hard part. What worries me the most is the length of the wires from the sensors to the processor. The use of shielded wires is recommended. Some electronic organs already have problems with long wires from the keyboard to the electronics. These wires will pick up RF signals that let the piano play if nobody is using the stairs. These wires can also radiate signals from the processor and cause interference on radio and TV reception. To solve these EMC-problems the best way is to use robust sensors and an interface/isolation board using optocouplers or relays between the sensors and the processor. To let it sound like music it is possible to program the adjacent stairs to play a tune. Then only the rhythm depends on the person using the stairs. You could play different tunes if somebody is going up or down the stairs.

Just to update this thread. I purchased an arduino with media shield. I soldered it together and it would power up but on loading the example software it would give an error.

I've been unable to fix this so that's were things have stalled. =(

What are you going to do next?

1.  Maybe remove the shield from the arduino.

2 Then possibly loand and run one of the blink programs.

3  Last resort:  use a magnifying glass and multimeter to find the soldering misunderstanding.