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Firmware update for Tic Stepper Motor Controllers, with new features including limit switches and homing

Posted by David on 5 February 2019
Tags: tic

Connecting a limit switch to the Tic (SCL, SDA, TX, and RX pins).

To go along with last week’s release of the Tic T249, we have also released a new version of the Tic firmware (version 1.06) for all Tic stepper motor controllers that adds several new features.

By popular demand, this new firmware version adds support for limit switches: any of the Tic control pins (SCL, SDA, TX, RX, or RC) can be configured as a digital input for a forward or reverse limit switch. When the limit switch is active, the Tic abruptly shuts down any movement in the specified direction, but allows the stepper motor to move in the other direction. You can use limit switches to help prevent your system from leaving its desired range of motion.

If you configure a limit switch, you can use the Tic’s new homing procedure. The new “Go home” command, which is available over serial, I²C, and USB, starts the homing procedure. The Tic will move in the direction specified by the command until it hits a limit switch for that direction. Then it will change directions, move until the limit switch deactivates, and set its current position to 0. The stepping speeds used by the Tic during the homing procedure are configurable.

You can also use the homing feature automatically, without sending a command. If automatic homing is enabled, the Tic performs the homing procedure whenever it is being commanded to go to a specific position but it is uncertain of its current position (e.g. immediately after motor power is applied). This feature can be handy if you are controlling the position of your stepper motor using an RC, analog, or quadrature encoder signal.

We have added a new section to the Tic user’s guide with detailed instructions for setting up limit switches and homing.

Example pin configuration for a Tic with limit switches.

New homing settings added in Tic firmware version 1.06.

The new firmware version also adds several features to the Tic’s TTL serial interface that make it more usable in systems with large numbers of Tics and in half-duplex serial busses. Specifically, it adds support for an alternative device number so any Tic can optionally be addressed by two different device numbers, and it adds an option to enable 14-bit device numbers so you can have more than 128 devices on a serial bus. The new firmware version also has an option to encode its serial responses using only bytes between 0 and 127, which can be useful in setups where the serial response from one Tic will be seen by other Tic devices, and you don’t want it to be misinterpreted as a command. We also implemented several changes to make the Tic less susceptible to noise on the serial lines, and you can now enable CRC bytes for serial responses sent by the Tic so that you can confirm the data you received matches what the Tic sent.

The Tic T249 was released with the latest firmware, so it has all of these new features, and we will be upgrading our existing Tics to this firmware version as we manufacture more. To gain access to these new features on your existing Tic controllers, you can download the latest configuration software and upgrade your device’s firmware to version 1.06. For more information, see the firmware upgrade instructions in the Tic user’s guide.

Macro photography using Tic stepper motor controllers

Posted by Jon on 4 February 2019

Mike’s portable stack & stitch image acquisition setup, which includes three Tic T500s.

Mike’s precision stack & stitch image acquisition setup, which includes three Tic T500s.

Forum member Mike is using our Tic stepper motor controllers in his automated stack & stitch image acquisition systems, which he has been using to get extremely high resolution images of various integrated circuits. Each system uses linear rails and stepper motors to properly align the camera/lens and the object to be photographed. Two stepper motors position the subject and a third adjusts how close the camera is to the subject. A Tic T500 controls each stepper motor and each Tic connects to a USB port on a Raspberry Pi 3B or Raspberry Pi 3B+, which acts as the main computer. Afterward, Mike stacks the images with Zerene Stacker and stitches them together with Photoshop. Some of his image sessions capture as many as 6000 individual images that are used to produce a single 300 megapixel image!

Zooming in on a stack & stitch test image.

A close-up view of a stack & stitch test image.

You can find more information about Mike’s stack & stitch image acquisition systems (like what specific mechanical hardware he is using) in this forum post. Also, to see and/or download a set of high resolution pictures taken with those setups, follow this link.

New product: Tic T249 USB Multi-Interface Stepper Motor Controller

Posted by David on 31 January 2019
Tags: new products tic
New product: Tic T249 USB Multi-Interface Stepper Motor Controller

I am excited to announce the release of the Tic T249 USB Multi-Interface Stepper Motor Controller, the fourth model in our line of Tic Stepper Motor Controllers. The Tic T249, which is based on the TB67S249FTG IC from Toshiba, features a broad 10 V to 47 V operating range and can deliver up to approximately 1.8 A per phase without a heat sink or forced air flow, making it our highest-power Tic yet. In addition to the array of high-level features offered by the other members of our Tic family, the Tic T249 offers access to several innovative features of the TB67S249FTG driver. Continued…

New Tic T500 revision to address problem with missed steps

Posted by Ben on 18 January 2019
Tags: tic
New Tic T500 revision to address problem with missed steps

One of the fun things you learn as an engineer is that physically laying out a circuit requires a lot more than simply confirming it matches the schematic. In practice, there are many more things to think about, and if you’ve seen datasheets with layout guidelines or recommendations, you’re probably aware of some of them. (Thermal considerations, adequate decoupling, minimizing parasitic inductance and capacitance…) What’s more, these considerations are often in conflict (e.g. is it better to have the decoupling capacitor closer to the IC or to have a wider trace for that high-current path?), and trouble can arise if you don’t correctly assess their relative importance. That is what happened to us with our Tic T500 stepper motor controller, where the location of a specific decoupling capacitor ended up being far more significant than we had anticipated. Continued…

PyTic - Python interface for Pololu Tic Stepper Motor Controllers

Posted by Kevin on 7 August 2018

Customer Daniel Castelli of the Allen Institute has released a Python package for interfacing with our Tic Stepper Motor Controllers. Currently, he only supports 64-bit Windows, but the source code is available and should be straightforward to extend to other operating systems. Here is example code using PyTic to control a stepper motor:

import pytic
from time import sleep

# - Initialization -------------------------------------------

tic = pytic.PyTic()

# Connect to first available Tic Device serial number over USB
serial_nums = tic.list_connected_device_serial_numbers()
tic.connect_to_serial_number(serial_nums[0])

# Load configuration file and apply settings
tic.settings.load_config('path\\to\\config.yml')
tic.settings.apply()                             

# - Motion Command Sequence ----------------------------------

# Zero current motor position
tic.halt_and_set_position(0)

# Energize Motor
tic.energize()
tic.exit_safe_start()

# Move to listed positions
positions = [1000, 2000, 3000, 0]
for p in positions:
  tic.set_target_position(p)
  while tic.variables.current_position != tic.variables.target_position:
    sleep(0.1)

# De-energize motor and get error status
tic.enter_safe_start()
tic.deenergize()
print(tic.variables.error_status)

The code and documentation for this package are available on GitHub.

Video: Getting Started with the Tic Stepper Motor Controllers

Posted by Emily on 21 March 2018

As I showed in my last post a few weeks ago, our Tic stepper motor controllers offer six different control interfaces so you can add stepper motors to a variety of projects. Getting started with the Tics is easy. This new video tutorial steps (see what I did there?) you through getting your stepper motor running with our Tic controllers:


As I was making this video, I realized one of the coolest things about the Tic is how quickly you can work out the capabilities of your stepper motor. Even if you’re comfortable using one of our stepper motor drivers along with a microcontroller, using the Tics makes adjusting settings like current limits, step rates, speed, and acceleration as quick as a click of the button, and you can control your motor directly from the software to make sure it’s behaving how you would like. So you might want to keep an extra Tic around for that purpose, just as a stepper motor tester.

Right now you can still purchase our newest Tic at a special introductory price of just $15.53 using the coupon code T500INTRO! (Click to add the coupon code to your cart.) We also cover shipping in the US! Note that this introductory offer applies only to the units without connectors soldered in.

New product: Tic T500 USB Multi-Interface Stepper Motor Controller

Posted by Jan on 14 March 2018

Our Tic stepper motor controllers are pretty awesome, and the new Tic T500 we released today should make stepper motors even more accessible for your next project. This latest version features a broad 4.5 V to 35 V operating range that covers everything from small 2-cell lithium battery packs up to 24 V batteries or power supplies while costing just $20 in single-piece quantities. This video gives you a quick overview of what the Tic stepper motor controllers offer:

The Tics make basic speed or position control of a stepper motor easy, with support for six high-level control interfaces:

  • USB for direct connection to a computer
  • TTL serial operating at 5 V for use with a microcontroller
  • I²C for use with a microcontroller
  • RC hobby servo pulses for use in an RC system
  • Analog voltage for use with a potentiometer or analog joystick
  • Quadrature encoder input for use with a rotary encoder dial, allowing full rotation without limits (not for position feedback)

The Tic T500 is available with connectors soldered in or without connectors soldered in. Here is a handy comparison chart with all three Tic stepper motor controllers:


Tic T500

Tic T834

Tic T825
Operating voltage range: 4.5 V to 35 V(1) 2.5 V to 10.8 V 8.5 V to 45 V(1)
Max current per phase
(no additional cooling):
1.5 A 1.5 A 1.5 A
Microstep resolutions: full
half
1/4
1/8
full
half
1/4
1/8
1/16
1/32
full
half
1/4
1/8
1/16
1/32
Automatic decay selection: Yes
Price (connectors not soldered): $19.95 $29.95 $29.95
Price (connectors soldered): $21.95 $31.95 $31.95

1 See product pages and user’s guide for operating voltage limitations.

Basically, the new T500 does not offer the finer microstep resolutions of the T834 and T825, and the T834 supports very low operating voltages while the T825 supports higher operating voltages.

For those of you interested in more of the details of the stepper motor driver, the Tic T500 uses the new MP6500 from MPS, which we also offer on some low-cost MP6500 breakout boards with analog (small trimmer potentiometer) and digital (via PWM) current limit setting options.

In keeping with the tradition we started this year, we are offering an extra discount for the first customers, to help share in our celebration of releasing a new product. The first hundred customers to use coupon code T500INTRO can get up to two units for just $15.53! (Click to add the coupon code to your cart.) And we’ll even cover the shipping in the US! Note that this introductory offer applies only to the units without connectors soldered in.

Video: Introducing the Tic Stepper Motor Controllers

Posted by Emily on 28 February 2018

Our Tic Stepper Motor Controllers make basic control of stepper motors easy. This quick video shows you all the control interfaces you can use with our Tics to add stepper motors to your projects:


Making this video was actually the first time I’ve had a chance to play around with the Tics, and I was pleasantly surprised at how quickly I was able to set up the Tic with each interface option. Once I had everything connected, it only took a few minutes using the control software to get things moving for each setup.

This video also gives a sneak peek of our new Tic T500 (the red Tics in the opening shot). Like our new stepper motor drivers, the T500s are based on the MPS MP6500 bipolar stepper motor driver. Keep an eye on this blog for their release in the coming weeks.

New product: Tic T834 USB Multi-Interface Stepper Motor Controller

Posted by David on 2 November 2017
Tags: new products tic

I am excited to announce our new product, the Tic T834 USB Multi-Interface Stepper Motor Controller. The Tic T834 is the second member of the Tic family of USB stepper motor controllers. It incorporates a TI DRV8834 driver, can operate from 2.5 V to 10.8 V, and can deliver up to approximately 1.5 A per phase without a heat sink or forced air flow.

Like the Tic T825, the Tic T834 makes basic speed or position control of a stepper motor easy, with support for six high-level control interfaces:

  • USB for direct connection to a computer
  • TTL serial operating at 5 V for use with a microcontroller
  • I²C for use with a microcontroller
  • RC hobby servo pulses for use in an RC system
  • Analog voltage for use with a potentiometer or analog joystick
  • Quadrature encoder input for use with a rotary encoder dial, allowing full rotation without limits (not for position feedback)

Tic T825 and T834 USB Multi-Interface Stepper Motor Controllers.

The Tic T834 is available with connectors soldered in or without connectors soldered in.

Introducing the Tic T825 USB Multi-Interface Stepper Motor Controller

Posted by David on 20 July 2017
Tags: new products tic

I am excited to announce our new product, the Tic T825 USB Multi-Interface Stepper Motor Controller. The Tic makes basic speed or position control of a stepper motor easy, with support for six high-level control interfaces:

  • USB for direct connection to a computer
  • TTL serial operating at 5 V for use with a microcontroller
  • I²C for use with a microcontroller
  • RC hobby servo pulses for use in an RC system
  • Analog voltage for use with a potentiometer or analog joystick
  • Quadrature encoder input for use with a rotary encoder dial, allowing full rotation without limits (not for position feedback)

You can select which of these interfaces you want to use and configure the other settings of the Tic over USB using our free software.

The Status tab of the Pololu Tic Control Center.

The Input and Motor Settings tab of the Pololu Tic Control Center.

The Tic T825 can operate from 8.5 V to 45 V and deliver up to approximately 1.5 A per phase continuously without a heat sink or forced air flow. With a digitally adjustable current limit that can be set over USB, serial, or I²C, you can save power while holding position or increase the motor’s torque while it is moving. The Tic offers six different step resolutions, from full step through 1/32-step (32 microsteps per full step). We designed the Tic’s firmware to be capable of taking up to 50,000 microsteps per second, which lets you use those finer microstepping modes while still keeping a high motor speed. The Tic also supports acceleration and deceleration limiting for smooth movements, and very slow speeds down to 1 step every 200 seconds (or 1 step every 1428 seconds with reduced resolution). The Tic T825 is based on the DRV8825 stepper motor driver IC from Texas Instruments (for which we also have a basic carrier board), and we plan to make other versions of the Tic that are based on different drivers with different performance characteristics.

Tic T825 USB Multi-Interface Stepper Motor Controller, bottom view with dimensions.

The Tic T825 is available with connectors soldered in or without connectors soldered in.

For RC/hobby servos, we have a similar family of products called the Maestro servo controllers. For brushed DC motors, we offer the Simple Motor Controllers and the Jrk Motor Controllers.

New Products

QTR-MD-07A Reflectance Sensor Array: 7-Channel, 8mm Pitch, Analog Output
STSPIN220 Low-Voltage Stepper Motor Driver Carrier (Header Pins Soldered)
Pololu 24V Step-Up/Step-Down Voltage Regulator S18V20F24
Tic T249 USB Multi-Interface Stepper Motor Controller (Connectors Soldered)
QTR-MD-16RC Reflectance Sensor Array: 16-Channel, 8mm Pitch, RC Output
QTR-HD-13RC Reflectance Sensor Array: 13-Channel, 4mm Pitch, RC Output
Tic T249 USB Multi-Interface Stepper Motor Controller
Free Circuit Cellar magazine January 2019
QTRX-MD-16A Reflectance Sensor Array: 16-Channel, 8mm Pitch, Analog Output, Low Current
QTRX-HD-25RC Reflectance Sensor Array: 25-Channel, 4mm Pitch, RC Output, Low Current
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