Missed the Kickstarter? No Problem! You can still purchase the Protractor and find the latest info at http://www.robogao.com
A lot of sensors can tell the distance to an object, but there just aren't any good ways to measure angles. Knowing the angle between your robot and nearby objects and open pathways is super useful, allowing your robot interact with its environment in real time. Challenges like obstacle avoidance, maze solving, mini sumo, and others are so much easier if you just know the angle. With a 180 degree field of view, the Protractor is a proximity sensor can tell you the angles to nearby objects as well as open pathways.
With just a few lines of code, your robot can be running mazes or obstacle courses simply by following the open pathway sensed by the Protractor.
Tired of your robot arm bumping into things? Make it a smart arm using a Protractor! With a Protractor mounted to your arm, you can spot objects before bumping into them and line up your gripper to make the grab.
The Protractor works great with the Pololu Zumo robot shield (Version 1.x). Our software library contains code for using the Protractor + Zumo for Mini Sumo matches as well as obstacle avoidance.
How it Works
The Protractor is an active infrared (IR) sensor. It measures the amount of light that bounces off nearby objects from different directions. A special algorithm processes the signals and calculates the angles to the objects it sees as well as the angles of the open paths.
The Protractor will output the angles whenever requested by a microcontroller. It can be connected using either I2C or Serial. Our Arduino Library makes it easy to get the angles from the Protractor.
The Protractor lets you know what it sees using its two blue LEDs. The brightness of the LEDs lets you quickly check how well the Protractor can see a nearby object.
Although the Protractor is not a distance measuring sensor, it does provide an indication of how visible an object is. When multiple objects or paths exist, knowing which object or path is most visible can help your robot decide which way to go.
How will the funds be used?
By supporting this Kickstarter, you're helping bring the Protractor to market. The funding goal has been set to cover the cost of the setup and materials for the first production run.
I have been working on the Protractor proximity sensor design for about two years and it is in its 5th design iteration. The Protractors in the pictures above were all fabricated and assembled by the production supplier. Minor improvements to the firmware are still in progress but are mainly focused on improved QA testing. The design and build of a functional test fixture is in progress and each Protractor will be thoroughly tested before shipping. The Protractor library has been tested to work with many different Arduino boards including the Uno, Mega, Leonardo, Due, Teensy 3.2 and 3.6.
Creation of a detailed Protractor User's Guide is in progress and will be made available a few weeks into the campaign with updates based on our Beta testers feedback.
Each Protractor comes with a Protractor circuit board, a stick of straight and right angle header and a capacitor. You will need to solder the header to the board. The capacitor will also need to be soldered if you wish to install it. Mounting hardware and hookup wires are not included.
The Protractor is fast, updating the angles every 15 milliseconds so your robot always has the latest information. While most proximity sensors have a very narrow view, the Protractor is designed to see a full 180 degrees in the plane of the board. When used indoors away from direct sunlight, the Protractor can generally see walls up to 35 to 40 cm (14 to16 in) away. A piece of 3” white PVC pipe can typically be seen 30 cm (12 in) away, and 1” white PVC pipe can typically be seen 20 cm (8 in) away. High levels of ambient infrared light will reduce the sensing range so shielding it from sunlight will keep it working well. The sensing range also depends on the amount of light reflected, so dark objects will have a reduced sensing range.
The Protractor is typically accurate to better than 10 degrees, with a slight taper in accuracy at the far ends of its angular range.
- Power Input: 6 to 14 Volt DC, can operate on 5V with modification
- Power Consumption: 10 to 85 ma average, 860 ma peak
- Communication Voltage: 2.7 to 5.5 V
- Emission Wavelength: 820 to 880 nm
- Refresh Rate: every 15 ms, adjustable
By default the Protractor scans every 15 milliseconds but can be set to scan slower or only when requested. Changing the refresh rate from 15 ms to 100 ms can reduce the average current from 85 ma to around 20 ma. The peak current draw of the Protractor is 860 ma and can be reduced to 200 ma or less by soldering the included capacitor to the board.
- Diameter: 89mm (3.5 in)
- Thickness: 6.2mm (0.25 in) excluding header
The board has 5 mounting holes that accept 4-40 or 3mm machine screws for mounting. Nylon or other plastic screws or standoffs are recommended.
Getting started with the Protractor and an Arduino is easy. A Protractor library with examples is available at: https://github.com/robogao/Protractor
- Number of objects and paths in view
- Angle to each object and path in view
- Visibility of each object and path in view
- Scan time
- LEDs behavior
- Serial baud rate
- I2C address
These are not part of the Kickstarter campaign and timeline but are on my to do list for making the Protractor easier to use in the future.
- Raspberry Pi Library
Any future libraries or enclosure designs would be made available for free.
With your support we've gone way beyond our initial goal. Thanks a bunch and here are some goodies to strive for:
500% Mounting Hardware
We'll throw in 3 sets of M3 Nylon screws, nuts and standoffs to help mount the Protractor on your next project.
1000% Hookup Wires
We'll throw in Male to Female jumper wires to help hook up the Protractor to your project.
Risks and challenges
Manufacturing will be the biggest challenge for rolling out the Protractor. A production supplier has already been selected and has built the Beta test units shown in the pictures and videos above. A few issues were discovered with the assembly process and have been corrected. There are a few minor changes planned for the PCB and a second run of Beta boards will be produced in parallel with the Kickstarter campaign with the goal of having zero changes and zero surprises between the final Beta and initial Production version.
The second biggest challenge will be quality testing of the production boards. The functional test plan has been designed and I have begun building the fixturing. The plan is to have all Protractor boards tested in house before shipping out to the backers. Depending on the number of backers this could constrain throughput and cause delays and I am currently working through plans to increase test capacity if the need arises.
Delivery of the early bird Protractor boards should begin 2-3 months after the Kickstarter campaign completes. The initial production run will be limited in quantity so that any potential issues can be addressed. If all goes well, a second run will kickoff with delivery 4-6 months after the campaign completes.
I have been designing custom circuit boards for about 4 years and this is my first Kickstarter. Hardware delivery can be challenging but I commit to doing everything I can to ensure a successful delivery to every backer. I greatly appreciate your interest and support in making this Kickstarter campaign successful and bringing the Protractor to life!Learn about accountability on Kickstarter
- (45 days)