Posts by Claire
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A few weeks ago I posted a tutorial on building a Raspberry Pi robot with the Romi 32U4 Control Board and Romi Chassis. Now we have a short video of the robot in action! For the full tutorial, see my earlier post.
This tutorial shows how to build a basic Raspberry Pi robot with the Romi chassis and the Romi 32U4 Control Board, our Arduino-compatible microcontroller board designed specifically for the Romi. With this setup, the powerful Raspberry Pi can take care of high-level tasks like motion planning, video processing, and network communication, while the Romi 32U4 Control Board takes care of low-level tasks that the Pi is incapable of, such as motor control and sensing. Continued…
With the holiday season upon us, many are on the hunt for interesting projects that we can give as gifts. This year, why not make your project about unveiling your gift? You would still have to get an actual gift to put inside the box, but you’d win major style points. Forum member Bob Day’s knock knock unlock puzzle box has no visible way of opening it, but given the right combination of knocks will unlatch itself with the help of a servo and several other electronic components inside. The puzzle box is controlled by an A-Star Micro, which is powered by our S7V8F5 voltage regulator and a mini LV pushbutton power switch. The power switch is turned on by a mercury tilt switch and turned off by the A-Star if no knocks are received for about 30 seconds. This power switch circuit allows power to be completely turned off, which should extend the battery life tremendously over just leaving the A-Star on. (For advanced microcontroller programmers, another option would be to put the A-Star into a low-power mode.) A list of the parts and connections used and some example code for the box are given on Bob’s blog.
“Knock Knock Unlock” Puzzle Box outside view.
If you found this project interesting, you might also like a similar GPS puzzle box, also created by Bob, that we featured on our blog last year. That box unlocked when brought to a specific location and included a simpler toggle switch for power and an LCD screen.
I am excited to announce that we just released our highest power regulators ever. The new D24V150Fx family of step-down regulators includes units with 3.3 V, 5 V, 6 V, 7.5 V, 9 V, and 12 V outputs and can output currents of around 15 A! With all of the output voltages available, the D24V150Fx family of regulators is great for a variety power-hungry projects like running servos or our metal gearmotors and supplying large LED displays.
The maximum continuous output currents for all the members of the D24V150Fx family are shown in the graph below. You can see that the available output current is generally a little higher for the lower-voltage versions than it is for the higher-voltage versions, and it decreases as the input voltage increases.
These regulators accept input voltages up to 40 V and have typical efficiencies between 80% and 95%. Integrated reverse-voltage protection, over-current protection, over-temperature shutoff, undervoltage lockout, and soft-start features make these regulators robust, and a power good output can be used to monitor the output voltage.
With Halloween on its way, and trick-or-treating eminent, you might be asking yourself if there are any alternative uses for the mountain of candy bars your kids will soon be bringing home. Well, customer Mike Kohn, whose projects we previously blogged about, has a solution for giving new life to not just candy, but all sorts of unwanted food items: remote controlled food!
For this project, Mike ditched plastic and aluminum and tried out a sampling of more savory chassis materials like candy bars, a carrot, a bell pepper, a grapefruit, and a chicken sausage. The candy bars, carrot, and sausage were used for four-wheeled differential drive cars and the pepper and grapefruit were used for boats. All the vehicles were actuated by a pair of micro metal gearmotors and the cars also used our 32mm wheels. Below is a picture of one car made with a 3 Musketeers bar.
Mike also wrote his own firmware for decoding the IR signals from a Syma S107 controller. You can find out which foods made the best chassis and plenty more information about the vehicles, including a parts list, schematic, and several other videos, on Mike’s website.
Forum member WaterBoy23 recently shared his robot which expanded upon the line following capabilities of our Zumo Robot for Arduino by adding in lane changing capabilities. The robot changes lanes when it detects a vehicle ahead of it, and is programmed to either pass the vehicle or return quickly to its original lane if it detects oncoming traffic. His robot uses two Arduino Uno boards, one for following the line and the other for reading ultrasonic position sensors. More information about the robot can be found in WaterBoy23’s post on our forum.
I’d like to introduce our latest addition to the Pololu stepper motor driver carrier family, the DRV8880 Stepper Motor Driver Carrier. This carrier for the Texas Instruments DRV8880 driver has the same form factor and basic layout as our A4988 carrier, which makes it a drop-in replacement in many systems. It also has a lot of the same features, like potentiometer adjustable current control and microstepping down to 1/16-step. In addition, the DRV8880 has many new features like inputs for dynamically scaling the current limit to 25%, 50%, 75%, or 100% of the limit set by the potentiometer, nine decay mode combinations, and autotune (insert Daft Punk joke here), which automatically selects the decay mode each PWM cycle for optimal current regulation performance.
The DRV8880 carrier has a maximum current of 1.6 A, and in our tests it could handle about 1 A per phase continuously. It has a 6.5 V to 45 V input voltage range, which is the widest of any of our stepper motor drivers, and it supports both 3.3 V and 5 V logic. For more information about our DRV8880 stepper motor driver carrier, please see its product page.
The local Las Vegas hackerspace, SYN Shop, hosted the third Las Vegas Mini Maker Faire at the Henderson Convention Center recently. The event showcased a wide variety of projects and skills: drones, sand casting metal using aluminum cans, woodworking, taiko drumming, and of course robots. At our booth, Pololu showed off some older demos, like our Simple Motor Controller demo and our jrk treasure chest; some newer demos, like the motion tracking skull from Halloween; and some fun robots, like the Zumo 32U4 and Paul’s Raspberry Pi Robot. Above is a short video with highlights from the event.
This robot, created by theophil on Let’s Make Robots, uses a Rover 5 chassis with encoders, a MinIMU, sonar sensors, and a few expansion plates to do room mapping. Theophil modified the chassis to use Dagu Wild Thumper wheels, and made a custom 3D-printed adapter for connecting the wheels in a compact way. The program for the robot, which is available on GitHub, collects data from the sonar sensors about how far away objects are and creates a grayscale map where the darkness of a pixel corresponds to the robot’s confidence that an obstacle exists in that spot.
Example map made by theophil’s mapping rover.
The program also includes a movement algorithm meant to drive the robot along paths that take it close to many obstacles to increase the accuracy of the sonar sensors. More about theophil’s room mapping robot can be found in his Let’s Make Robots post.
Forum member spiked3, whom we previously posted about, has shared another robot with a custom laser cut chassis. The new robot uses his own custom Arduino shield, the S3-Pilot, which has sockets for an IMU and two of our MC33926 Motor Driver Carriers.
Custom Arduino shield created by forum member spiked3.
The MC33926 drivers control two 37D motors with encoders, and the encoder signals are processed by the Arduino. The robot also includes a lidar, PIXY Cam, and Raspberry Pi. The on-board IMU and encoders allow the robot to keep track of where it is and what direction it is facing, so spiked3 was able to implement a high-level interface for the robot that accepts movement commands like “go forward three meters” or “turn a certain number of degrees to the right”.
You can find out more about this robot and see some videos of it being tested on spiked3’s blog.