After this tutorial, you will be able to control Ableton Live instruments or devices with the motion of you hand. We will build the hardware circuit, write the Arduino code, construct the Max patch and put it all together! No soldering required!
If you are new to these concepts I suggest following along with my previous tutorial which is more of an entry level tutorial, while this one is more involved.
What you will need to follow along.
DOWNLOAD: Finished Max Patch and Arduino Sketch
The hardware setup for this project is quite simple. Make sure the Arduino is not being powered. Take a look at the Ultrasonic Ranging Module. It has 2cm - 400cm non-contact measurement functionality, with ranging accuracy that can reach up to 3mm. It sends out 8 cycle 40 kHz signal busts and waits until it gets the bust back by way of reflection. Then it does some math to figure out the distance depending on how long the reflection takes to return.
If you would like to see the full specs for the module click the link here.
There should be 4 pins extruding from one side. They are labeled VCC, Trig, Echo, GND.
The VCC stands for Voltage at Common Collector. We will want to run a jumper wire from it to one of the 5V pins on the Arduino.
The Trig is short for trigger. You send a pulse to the trigger to start the module ranging. We need to put this into any of the digital pins on the Arduino. I am using digital pin 12.
The Echo waits and calculates the distance if an echo is received. We need to put this into any of the digital pins on the Arduino. I am using digital pin ~11.
The GND is short of Ground. We need to connect this to one of the Arduino’s GND pins.
Now, beyond plugging the Arduino into the computer we are done. Can you believe it? Let’s move on to the Arduino Sketch.
Below you will find a photo of the Arduino Sketch. I suggest you copy it from the picture. Copy it word for word. I have added a good deal of comments to explain what each line of the code is doing. Copying it will help you understand what is going on better than if you just download it and don’t take a critical look.
Though if you want, the sketch is available in the download for this project.
Plug in your Arduino if it isn’t already.
Once you have the code written, or loaded, you need to make sure your device and the correct port are selected before you can upload. Go to Tools in the main menu of the software and make sure your Arduino type is selected.
Now, if you are like me, and you like your code to look beautiful, there is a neat option in the Tools menu. It is at the top and it’s called “Auto Format” (Ctrl+T). This will read your code and make any changes to the formatting.
Click the Check Mark in the top left to Verify the code. If you are good to go and have no errors, which should be the case if you did things correctly, hit the Right-Facing Arrow to upload the Sketch to the Arduino.
Once done you should see a message saying it was uploaded successfully. Now, we can verify that everything is working. Wave your hand in front of the sensor. You should see the LED on the Arduino turn off when your hand is in range. Remember there will be a slight delay, so don’t panic!
We can also verify that the numbers are being printed correctly by opening the Arduino Software’s Serial Monitor. It’s the little magnifying glass icon in the top right of the program. When there is nothing in front of the sensor it should just be printing -1 after -1. Then if you wave your hand in front of it you should see values. Moving your hand closer should result in smaller numbers and farther away will get larger numbers. Those numbers are the distance in Centimeters.
The only numbers you need to make a serious note of are the max & minimumRange values. These determine how far the sensor will be looking for movement. So, if you want a longer or shorter range you need to update the values in the sketch and re-upload to the Arduino. Then you need to change the input min/max on the “scale” object in the Max patch, more on that in a bit.
Originally, I went ahead and made an entire, albeit basic, Max patch that worked with the Dry/Wet parameter of the simple delay. However, there were a number of issues with that. Like, for instance, not all parameters have uniform minimum and maximum values. The reverb’s decay time is drastically different form the Dry/Wet parameter, for example.
In order to save time and headaches for those who are just looking to get this thing working I chose to modify one of the example Max API devices. Specifically, the Max.API.DeviceParam device. I went with this one because of its incredible versatility and of course how well it was made.
Max.API.DeviceParam device allows you can choose any device in the set from any channel, the return tracks or the master.
That can be found in the Max for Live browser window -> Max Audio Effect -> Max.API.DeviceParam
Using Max.API.DeviceParam gets us most of the way the way to success town, but we need to modify it to get and use the information (data) being sent from the Arduino & Sensor into the computer.
After you load with the Max.API.DeviceParam you should immediately go to “Save As” and rename it so we can avoid messing up the original device if anything goes wrong.
Go ahead and open Max for Live by clicking the edit button on the device. Unfreeze and then go into patching mode. Double click the object called “patcher Properties”. This is a subpatcher and that is where we need to do our editing.
NOTE* The main device needs to be locked when you double click if you are looking to edit the subpatcher.
Now we need to add the following objects into the patch.
Everything that is red in the photo below is what we need to add in order to make this patch communicate correctly with the Arduino.
The print button will help to make sure you have the correct COM referenced.
Essentially what is happening with the additions is that we are telling Max to open a “serial connection”, info passing over USB, and look for any data being sent out. That data is read, interpreted and translated into numbers Max can work with.
Those numbers are passed into a scale object. The scale object makes everything nice and neat. The first two values are the min and max coming out of the Arduino, which you might remember from the Sketch (min 0, max 30). Then the second two numbers are the new min and max values the input is scaled two which come from whichever device we have selected. Then the new scaled values will control the “live.property value @observe 1“ which will then update and control whichever parameter we have selected in Live
There you go. I hope your custom DIY motion controller is working at this point and maybe you learned a thing or two along the way!
I want to give a special shout out to Michael Mckellar for helping to get me started with the base for the Arduino Sketch and Max patch.