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Comments by Brandon
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Jeremy's line following robot: Zumo Slim
- 16 September 2021Hello.
We noticed that you asked similar questions on a few of these line-follower blog posts; we do not have all of these line following robots accessible anymore to measure them, but they all use a similar strategy with the motors in the rear and the line sensor extended toward the front.
The ideal distance between the ground and the sensor depends on the specific sensor you are using. We list the "Optimal sensing distance" for our QTR reflectance sensors on their respective product pages.
As far as the algorithm, most of our line following robots have used PID control. You can find a good breakdown of how this works from the "Example Project #1: Line Following" section from our 3pi Robot's user's guide.
If you are looking for more advice or have more questions about using our parts in a line following robot, I recommend posting a request for help on our forum.
Brandon
New product: Breakout Board for microSD Card with 3.3V Regulator and Level Shifters
- 6 August 2021Hello, Adam.
It should work fine with 3.3V logic, but you might consider powering the board with a 3.3V source through the "3V3 (OUT)" pin and leaving the VDD pin disconnected to bypass the onboard regulator. Alternatively, you might consider using the simple breakout board for microSD cards since you do not need the additional level shifters.
Brandon
New Tic T500 revision to address problem with missed steps
- 8 June 2021Hello, Israel.
It is not clear to me what exactly you are trying to do, but this is not an appropriate place to answer detailed questions or get into troubleshooting. You might consider posting a request for help on our forum and include a lot more details about what you are doing. Alternatively, you can email us at support@pololu.com.
Brandon
New Product: 5V, 5A Step-Down Voltage Regulator D24V50F5
- 13 April 2021Hello, Don.
Microcontrollers usually have a diode going from each I/O pin to its logic supply. These diodes clamp the voltage on the pins, preventing pull-up resistors like the one on the D24D50F5 board from pulling the pins too high (and the resistor limits the current through the diode), so it is probably fine. However, if you want to be extra safe and not rely on the clamping diodes, you could remove the pull-up resistor from the regulator. The pull-up resistor is the small black component labeled "01D" near the mounting hole in the bottom right-hand corner of this picture of the underside of the regulator.
Brandon
New products (and demo): Force-sensing linear potentiometers and resistors
- 9 March 2021Hello, Paul.
The code for the FSLP demo program shown in the video is linked to in the post above, and you can find it under the
"Resources" tab of the Force-Sensing Linear Potentiometer: 4.0″×0.4″ Strip product page as well.
Brandon
New product: A-Star 328PB Micro
- 18 February 2021The "Connecting to the serial interface" section of the A-Star 328PB User's Guide has instructions specifically for using our USB AVR Programmer v2.1, including a picture of the connected boards. If you requesting something beyond what we already have there, can you elaborate?
Brandon
Brandon's line following robot: The Chariot
- 8 December 2020Hello, Sultan.
The main reason I used a voltage regulator was to keep the motor voltage consistent even when the batteries start draining or get freshly charged. I noticed with my previous line followers that I would spend a good deal of time increasing the speed and tuning the robot, only to have the performance get worse when I recharged the batteries. I prefer a regulated motor supply voltage to keep the robot's performance predictable, especially during a competition when you might not have time to fully charge your batteries between each run.
I have not tried a swivel caster with a robot of this scale, but in my experience with larger robots, swivel casters tend to re-direct the robot when attempting to turn since they are directional. The benefit of using a ball caster is that it can freely move in any direction at any time. Since your robot will be on a carpeted surface, you might consider using a larger ball caster than the 3/8" one I used. We carry some all the way up to 1" diameter.
Brandon
New product: Pololu Dual MC33926 Motor Driver for Raspberry Pi
- 11 September 2020Hello, Alex.
I am glad you found the example Jeremy posted for how to drive a stepper motor using the MC33926 Motor Driver Shield for Arduino. However, please note that a few posts later, he posted an improved version that fixes a mistake and adds the ability to limit the maximum coil voltage to prevent damage to your motor if you are using a stepper motor with a rated voltage lower than the MC33926 shield's.
Additionally, while it is possible to drive a stepper motor with this shield, we generally recommend one of our many dedicated stepper motor drivers. or controllers instead. They offer more advanced features like current limiting, multiple step resolutions (some down to 1/256), and come in a much more compact size. Some of the drivers have higher level interface options like SPI, and our Tic stepper motor controllers offer many interface options including USB, TTL serial, I2C, hobby RC, analog voltage, and quadrature encoder input as well as the more standard STEP/DIR inputs. They also have settings that can be configured to control the speed profile, limit switches, a homing procedure, and much more.
Brandon
PID line follower with 5" robot chassis
- 28 August 2020Hello, Matty.
You could add your own reverse voltage protection circuit to the Vcc pin. By the way, just to be clear, reverse voltage protection is to prevent damage in the situation where the Vcc connection is accidentally made with the wrong polarity (e.g. connecting ground to Vcc and your logic voltage to ground). So, if you put together your system in a way that the Vcc connection is made through a keyed connector, that might also be a solution.
If you have additional questions or concerns, please post on our forum, which is more suited for technical discussions, and we would be glad to continue the discussion there.
Brandon
New products: Discrete addressable through-hole RGB LEDs
- 22 May 2020Hello, Paul.
Thank you for sharing your solution to the problem you encountered!
Brandon