Next Newsletter: Embedded Boards

Coming to your inbox tomorrow: Circuit Cellar’s Embedded Boards newsletter. Tomorrow’s newsletter content focuses on both standard and non-standard embedded computer boards that ease prototyping efforts and let you smoothly scale up to production volumes.

Bonus: We’ve added Drawings for Free Stuff to our weekly newsletters. Make sure you’ve subscribed to the newsletter so you can participate.

Already a Circuit Cellar Newsletter subscriber? Great!
You’ll get your
Embedded Boards newsletter issue tomorrow.

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Our weekly Circuit Cellar Newsletter will switch its theme each week, so look for these in upcoming weeks:

October has a 5th Tuesday. That’s means we’re giving you an extra Newsletter: Technologies for Drone Design! (10/29) Consumer and commercial drones rank as one of the most dynamic areas of embedded design today. Chip, board and system suppliers are offering improved ways for drones to do more processing on board the drone, while also providing solutions for implementing the control, comms and video subsystems in drones. This newsletter explores all these technology areas.

Analog & Power. (11/5) This newsletter content zeros in on the latest developments in analog and power technologies including DC-DC converters, AC-DC converters, power supplies, op amps, batteries and more.

Microcontroller Watch (11/12) This newsletter keeps you up-to-date on latest microcontroller news. In this section, we examine the microcontrollers along with their associated tools and support products.

IoT Technology Focus. (11/19) Covers what’s happening with Internet-of-Things (IoT) technology–-from devices to gateway networks to cloud architectures. This newsletter tackles news and trends about the products and technologies needed to build IoT implementations and devices.

Tuesday’s Newsletter: IoT Tech Focus

Coming to your inbox tomorrow: Circuit Cellar’s IoT Technology Focus newsletter. Tomorrow’s newsletter covers what’s happening with Internet-of-Things (IoT) technology–-from devices to gateway networks to cloud architectures. This newsletter tackles news and trends about the products and technologies needed to build IoT implementations and devices.

Bonus: We’ve added Drawings for Free Stuff to our weekly newsletters. Make sure you’ve subscribed to the newsletter so you can participate

Already a Circuit Cellar Newsletter subscriber? Great!
You’ll get your IoT Technology Focus newsletter issue tomorrow.

Not a Circuit Cellar Newsletter subscriber?
Don’t be left out! Sign up now:

Our weekly Circuit Cellar Newsletter will switch its theme each week, so look for these in upcoming weeks:

Embedded Boards.(10/22) The focus here is on both standard and non-standard embedded computer boards that ease prototyping efforts and let you smoothly scale up to production volumes.

October has a 5th Tuesday. That’s means we’re giving you an extra Newsletter: Technologies for Drone Design! (10/29) Consumer and commercial drones rank as one of the most dynamic areas of embedded design today. Chip, board and system suppliers are offering improved ways for drones to do more processing on board the drone, while also providing solutions for implementing the control, comms and video subsystems in drones. This newsletter explores all these technology areas.

Analog & Power. (11/5) This newsletter content zeros in on the latest developments in analog and power technologies including DC-DC converters, AC-DC converters, power supplies, op amps, batteries and more.

Microcontroller Watch (11/12) This newsletter keeps you up-to-date on latest microcontroller news. In this section, we examine the microcontrollers along with their associated tools and support products.

Tuesday’s Newsletter: Microcontroller Watch

Coming to your inbox tomorrow: Circuit Cellar’s Microcontroller Watch newsletter. Tomorrow’s newsletter keeps you up-to-date on latest microcontroller news. In this section, we examine microcontrollers along with their associated tools and support products.

Bonus: We’ve added Drawings for Free Stuff to our weekly newsletters. Make sure you’ve subscribed to the newsletter so you can participate.

Already a Circuit Cellar Newsletter subscriber? Great!
You’ll get your Microcontroller Watch newsletter issue tomorrow.

Not a Circuit Cellar Newsletter subscriber?
Don’t be left out! Sign up now:

Our weekly Circuit Cellar Newsletter will switch its theme each week, so look for these in upcoming weeks:

IoT Technology Focus. (10/15) Covers what’s happening with Internet-of-Things (IoT) technology–-from devices to gateway networks to cloud architectures. This newsletter tackles news and trends about the products and technologies needed to build IoT implementations and devices.

Embedded Boards.(10/22) The focus here is on both standard and non-standard embedded computer boards that ease prototyping efforts and let you smoothly scale up to production volumes.

October has a 5th Tuesday. That’s means we’re giving you an extra Newsletter: Technologies for Drone Design! (10/29) Consumer and commercial drones rank as one of the most dynamic areas of embedded design today. Chip, board and system suppliers are offering improved ways for drones to do more processing on board the drone, while also providing solutions for implementing the control, comms and video subsystems in drones. This newsletter explores all these technology areas.

Analog & Power. (11/5) This newsletter content zeros in on the latest developments in analog and power technologies including DC-DC converters, AC-DC converters, power supplies, op amps, batteries and more.

Tuesday’s Newsletter: Analog & Power

Coming to your inbox on Tuesday: Circuit Cellar’s Analog & Power newsletter. This newsletter content zeros in on the latest developments in analog and power technologies including ADCs, DACs, DC-DC converters, AC-DC converters, power supplies, op amps, batteries and more.

Bonus: We’ve added Drawings for Free Stuff to our weekly newsletters. Make sure you’ve subscribed to the newsletter so you can participate.

Already a Circuit Cellar Newsletter subscriber? Great!
You’ll get your Analog & Power newsletter issue tomorrow.

Not a Circuit Cellar Newsletter subscriber?
Don’t be left out! Sign up now:

Our weekly Circuit Cellar Newsletter will switch its theme each week, so look for these in upcoming weeks:

Microcontroller Watch. (10/8) This newsletter keeps you up-to-date on latest microcontroller news. In this section, we examine the microcontrollers along with their associated tools and support products.

IoT Technology Focus. (10/15) Covers what’s happening with Internet-of-Things (IoT) technology–-from devices to gateway networks to cloud architectures. This newsletter tackles news and trends about the products and technologies needed to build IoT implementations and devices.

Embedded Boards.(10/22) The focus here is on both standard and non-standard embedded computer boards that ease prototyping efforts and let you smoothly scale up to production volumes.

Next Newsletter: Embedded Boards

Coming to your inbox tomorrow: Circuit Cellar’s Embedded Boards newsletter. Tomorrow’s newsletter content focuses on both standard and non-standard embedded computer boards that ease prototyping efforts and let you smoothly scale up to production volumes.

Bonus: We’ve added Drawings for Free Stuff to our weekly newsletters. Make sure you’ve subscribed to the newsletter so you can participate.

Already a Circuit Cellar Newsletter subscriber? Great!
You’ll get your
Embedded Boards newsletter issue tomorrow.

Not a Circuit Cellar Newsletter subscriber?
Don’t be left out! Sign up now:

Our weekly Circuit Cellar Newsletter will switch its theme each week, so look for these in upcoming weeks:

Analog & Power. (10/1) This newsletter content zeros in on the latest developments in analog and power technologies including DC-DC converters, AC-DC converters, power supplies, op amps, batteries and more.

Microcontroller Watch (10/8) This newsletter keeps you up-to-date on latest microcontroller news. In this section, we examine the microcontrollers along with their associated tools and support products.

IoT Technology Focus. (10/15) Covers what’s happening with Internet-of-Things (IoT) technology–-from devices to gateway networks to cloud architectures. This newsletter tackles news and trends about the products and technologies needed to build IoT implementations and devices.

Tuesday’s Newsletter: IoT Tech Focus

Coming to your inbox tomorrow: Circuit Cellar’s IoT Technology Focus newsletter. Tomorrow’s newsletter covers what’s happening with Internet-of-Things (IoT) technology–-from devices to gateway networks to cloud architectures. This newsletter tackles news and trends about the products and technologies needed to build IoT implementations and devices.

Bonus: We’ve added Drawings for Free Stuff to our weekly newsletters. Make sure you’ve subscribed to the newsletter so you can participate

Already a Circuit Cellar Newsletter subscriber? Great!
You’ll get your IoT Technology Focus newsletter issue tomorrow.

Not a Circuit Cellar Newsletter subscriber?
Don’t be left out! Sign up now:

Our weekly Circuit Cellar Newsletter will switch its theme each week, so look for these in upcoming weeks:

Embedded Boards.(9/24) The focus here is on both standard and non-standard embedded computer boards that ease prototyping efforts and let you smoothly scale up to production volumes.

Analog & Power. (10/1) This newsletter content zeros in on the latest developments in analog and power technologies including DC-DC converters, AC-DC converters, power supplies, op amps, batteries and more.

Microcontroller Watch (10/8) This newsletter keeps you up-to-date on latest microcontroller news. In this section, we examine the microcontrollers along with their associated tools and support products.

Tuesday’s Newsletter: Microcontroller Watch

Coming to your inbox tomorrow: Circuit Cellar’s Microcontroller Watch newsletter. Tomorrow’s newsletter keeps you up-to-date on latest microcontroller news. In this section, we examine microcontrollers along with their associated tools and support products.

Bonus: We’ve added Drawings for Free Stuff to our weekly newsletters. Make sure you’ve subscribed to the newsletter so you can participate.

Already a Circuit Cellar Newsletter subscriber? Great!
You’ll get your Microcontroller Watch newsletter issue tomorrow.

Not a Circuit Cellar Newsletter subscriber?
Don’t be left out! Sign up now:

Our weekly Circuit Cellar Newsletter will switch its theme each week, so look for these in upcoming weeks:

IoT Technology Focus. (9/17) Covers what’s happening with Internet-of-Things (IoT) technology–-from devices to gateway networks to cloud architectures. This newsletter tackles news and trends about the products and technologies needed to build IoT implementations and devices.

Embedded Boards.(9/24) The focus here is on both standard and non-standard embedded computer boards that ease prototyping efforts and let you smoothly scale up to production volumes.

Analog & Power. (10/1) This newsletter content zeros in on the latest developments in analog and power technologies including DC-DC converters, AC-DC converters, power supplies, op amps, batteries and more.

Offloading Intelligence

A Robotics Example

While some embedded systems do just fine with a single microcontroller, there are circumstances when offloading some processing into a second processing unit, such as a second MCU, offers a lot of advantages. In this article, Jeff explores this situation in the context of a robotic system project that uses Arduino and an external motor driver.

By Jeff Bachiochi

When your tasks begin to slip, it might be time to get help. At home, when the job jar begins to overflow, it’s often time to call in a professional to fix the leak, repaint, change the oil and so forth. At work, your project might require additional help from a programmer, purchaser, designer, or other specialist. I believe a good manager is one who is able to handle any facet of the project, but can also step back and let those associates handle their areas of expertise without micromanaging.

And so it is with programming a MCU. You can write the project yourself or—with confidence in your function library—you can make calls to complete a task without having to code those library functions. You can do more by having to do less. All that said, computationally intensive routines can eat up all your computing power. This might suggest that you move up to a more capable processor, or divide and conquer the project by using multiple MCUs.

Case in Point

I have a robot wheel base that uses an Arduino and an external motor driver board. The motors required more than the typical 2 A most Arduino motor shields can provide, so I went to an external motor driver for about $20. This requires direction and speed control outputs for each of the two motors. The wheel encoders require phase A and phase B inputs for each wheel.

It wasn’t long until the basic movement routines were written. Then I added encoder routines to handle measuring wheel movements. Finally, I made routines for adding acceleration/deceleration, positional and speed cooperation between the wheels. At that point, it was becoming clear that I was going to run out of processing power and application space. And I had not yet added a single sensor!

I considered using this Arduino as a separate processor just for wheel base movement. Certainly, someone must have integrated an MCU with motor drivers. Enter the motor controller. I chose to use a Basicmicro Roboclaw 2x7A motor controller (Figure 1) [1]. This is the smallest in a line of compatible controllers. At $70, it cost more than my motor driver. However, it incorporates the use of the wheel encoders, so it has some pretty good intelligence. It can handle two motors at 7 A of continuous current each. I like the fact that I can substitute other models should I need more current—up to 2 x 160 A!

Figure 1
Basicmicro’s Roboclaw motor controller [1] handles two motors and associated wheel encoders. This allows the user to command motor movements without needing to drive motor phases or count wheel encoder outputs. Its on-board MCU offloads the need to deal with low-level functions.


While I plan to connect this via serial to the Arduino, it can be used stand-alone with an RC receiver, or with analog inputs from potentiometers. The serial link can be “simple” TX only or “packet” TX/RX to provide feedback.

Stall Current

Your motor (and gearing system) can produce some maximum torque or rotational force on a wheel to overcome the load or weight of the robot. Larger loads require more torque. Motors are rated by the maximum torque they can produce. The load or resistance to move must be less than the motor torque, or the motor will not be able to move the load. This is the stalled state of the motor, and will draw maximum current, the “stall state current.” Motor drivers must be able to withstand this current, or the driver will be destroyed trying to dissipate excess heat—not to mention overheating the motor.

Starting from a standstill will most likely require this current until movement has started. High currents while starting are typical but temporary. As the speed increases, the torque required goes down, and so does the current. With the load completely removed, the motor rotates at its maximum speed, requiring minimum current. You will typically see this “no-load” rating (no-load current vs. speed) for a motor. You may also see a continuous current rating. This will be much less than the stall current, and your motor selection should be based on the ability to provide the required torque to run continuously without exceeding the continuous current rating. This is assuming you will need to run continuously.

I’ve measured the stall current of my wheel assembly and found it to be around 5 A. The no-load current is 1 A. The calculated stall torque at the wheel is about 44 foot-pounds (ft-lb) of force after all the gearing. That may sound like a lot, but this robot carries three gel-cell batteries, and the batteries themselves are over 22 lbs. Besides the six motor/power connections, there are seven other control inputs. Two of these are relegated to the wheel encoders, and two are for the motor control mode. The last three are up for grabs, but have specific functions that you might need, depending on the control mode chosen. For instance, if you are using the controller for a remote control (RC) vehicle, you might want to use S3 for a flip input. This input reverses the direction controls when it detects that the vehicle has been flipped upside down, like in the Robot Wars TV show. …

Read the full article in the September 350 issue of Circuit Cellar
(Full article word count: 3231 words; Figure count: 4 Figures. plus 9 code Listings).

Don’t miss out on upcoming issues of Circuit Cellar. Subscribe today!

Note: We’ve made the October 2017 issue of Circuit Cellar available as a free sample issue. In it, you’ll find a rich variety of the kinds of articles and information that exemplify a typical issue of the current magazine.

Tuesday’s Newsletter: Analog & Power

Coming to your inbox on Tuesday: Circuit Cellar’s Analog & Power newsletter. This newsletter content zeros in on the latest developments in analog and power technologies including ADCs, DACs, DC-DC converters, AC-DC converters, power supplies, op amps, batteries and more.

Bonus: We’ve added Drawings for Free Stuff to our weekly newsletters. Make sure you’ve subscribed to the newsletter so you can participate.

Already a Circuit Cellar Newsletter subscriber? Great!
You’ll get your Analog & Power newsletter issue tomorrow.

Not a Circuit Cellar Newsletter subscriber?
Don’t be left out! Sign up now:

Our weekly Circuit Cellar Newsletter will switch its theme each week, so look for these in upcoming weeks:

Microcontroller Watch. (9/10) This newsletter keeps you up-to-date on latest microcontroller news. In this section, we examine the microcontrollers along with their associated tools and support products.

IoT Technology Focus. (9/17) Covers what’s happening with Internet-of-Things (IoT) technology–-from devices to gateway networks to cloud architectures. This newsletter tackles news and trends about the products and technologies needed to build IoT implementations and devices.

Embedded Boards.(9/24) The focus here is on both standard and non-standard embedded computer boards that ease prototyping efforts and let you smoothly scale up to production volumes.

Next Newsletter: Embedded Boards

Coming to your inbox tomorrow: Circuit Cellar’s Embedded Boards newsletter. Tomorrow’s newsletter content focuses on both standard and non-standard embedded computer boards that ease prototyping efforts and let you smoothly scale up to production volumes.

Bonus: We’ve added Drawings for Free Stuff to our weekly newsletters. Make sure you’ve subscribed to the newsletter so you can participate.

Already a Circuit Cellar Newsletter subscriber? Great!
You’ll get your
Embedded Boards newsletter issue tomorrow.

Not a Circuit Cellar Newsletter subscriber?
Don’t be left out! Sign up now:

Our weekly Circuit Cellar Newsletter will switch its theme each week, so look for these in upcoming weeks:

Analog & Power. (9/3) This newsletter content zeros in on the latest developments in analog and power technologies including DC-DC converters, AC-DC converters, power supplies, op amps, batteries and more.

Microcontroller Watch (9/10) This newsletter keeps you up-to-date on latest microcontroller news. In this section, we examine the microcontrollers along with their associated tools and support products.

IoT Technology Focus. (9/17) Covers what’s happening with Internet-of-Things (IoT) technology–-from devices to gateway networks to cloud architectures. This newsletter tackles news and trends about the products and technologies needed to build IoT implementations and devices.

Tuesday’s Newsletter: Microcontroller Watch

Coming to your inbox tomorrow: Circuit Cellar’s Microcontroller Watch newsletter. Tomorrow’s newsletter keeps you up-to-date on latest microcontroller news. In this section, we examine microcontrollers along with their associated tools and support products.

Bonus: We’ve added Drawings for Free Stuff to our weekly newsletters. Make sure you’ve subscribed to the newsletter so you can participate.

Already a Circuit Cellar Newsletter subscriber? Great!
You’ll get your Microcontroller Watch newsletter issue tomorrow.

Not a Circuit Cellar Newsletter subscriber?
Don’t be left out! Sign up now:

Our weekly Circuit Cellar Newsletter will switch its theme each week, so look for these in upcoming weeks:

IoT Technology Focus. (8/20) Covers what’s happening with Internet-of-Things (IoT) technology–-from devices to gateway networks to cloud architectures. This newsletter tackles news and trends about the products and technologies needed to build IoT implementations and devices.

Embedded Boards.(8/27) The focus here is on both standard and non-standard embedded computer boards that ease prototyping efforts and let you smoothly scale up to production volumes.

Analog & Power. (9/3) This newsletter content zeros in on the latest developments in analog and power technologies including DC-DC converters, AC-DC converters, power supplies, op amps, batteries and more.

Tuesday’s Newsletter: Analog & Power

Coming to your inbox on Tuesday: Circuit Cellar’s Analog & Power newsletter. This newsletter content zeros in on the latest developments in analog and power technologies including ADCs, DACs, DC-DC converters, AC-DC converters, power supplies, op amps, batteries and more.

Bonus: We’ve added Drawings for Free Stuff to our weekly newsletters. Make sure you’ve subscribed to the newsletter so you can participate.

Already a Circuit Cellar Newsletter subscriber? Great!
You’ll get your Analog & Power newsletter issue tomorrow.

Not a Circuit Cellar Newsletter subscriber?
Don’t be left out! Sign up now:

Our weekly Circuit Cellar Newsletter will switch its theme each week, so look for these in upcoming weeks:

Microcontroller Watch. (8/13) This newsletter keeps you up-to-date on latest microcontroller news. In this section, we examine the microcontrollers along with their associated tools and support products.

IoT Technology Focus. (8/20) Covers what’s happening with Internet-of-Things (IoT) technology–-from devices to gateway networks to cloud architectures. This newsletter tackles news and trends about the products and technologies needed to build IoT implementations and devices.

Embedded Boards.(8/27) The focus here is on both standard and non-standard embedded computer boards that ease prototyping efforts and let you smoothly scale up to production volumes.

Bonus Newsletter: PCB Design Tools

We have a BONUS newsletter for you this week: PCB Design Tools! The process of PCB design is always facing new complexities. Rules-based autorouting, chips with higher lead counts and higher speed interconnections are just a few of the challenges forcing PCB design software to keep pace. This newsletter updates you on the latest happenings in this area.

Bonus: We’ve added Drawings for Free Stuff to our weekly newsletters. Make sure you’ve subscribed to the newsletter so you can participate.

Already a Circuit Cellar Newsletter subscriber? Great!
You’ll get your
Embedded Boards newsletter issue tomorrow.

Not a Circuit Cellar Newsletter subscriber?
Don’t be left out! Sign up now:

Our weekly Circuit Cellar Newsletter will switch its theme each week, so look for these in upcoming weeks:

Analog & Power. (8/6) This newsletter content zeros in on the latest developments in analog and power technologies including DC-DC converters, AC-DC converters, power supplies, op amps, batteries and more.

Microcontroller Watch (8/13) This newsletter keeps you up-to-date on latest microcontroller news. In this section, we examine the microcontrollers along with their associated tools and support products.

IoT Technology Focus. (8/20) Covers what’s happening with Internet-of-Things (IoT) technology–-from devices to gateway networks to cloud architectures. This newsletter tackles news and trends about the products and technologies needed to build IoT implementations and devices.

Embedded Boards.(8/27) The focus here is on both standard and non-standard embedded computer boards that ease prototyping efforts and let you smoothly scale up to production volumes

Next Newsletter: Embedded Boards

Coming to your inbox tomorrow: Circuit Cellar’s Embedded Boards newsletter. Tomorrow’s newsletter content focuses on both standard and non-standard embedded computer boards that ease prototyping efforts and let you smoothly scale up to production volumes.

Bonus: We’ve added Drawings for Free Stuff to our weekly newsletters. Make sure you’ve subscribed to the newsletter so you can participate.

Already a Circuit Cellar Newsletter subscriber? Great!
You’ll get your
Embedded Boards newsletter issue tomorrow.

Not a Circuit Cellar Newsletter subscriber?
Don’t be left out! Sign up now:

Our weekly Circuit Cellar Newsletter will switch its theme each week, so look for these in upcoming weeks:

July has a 5th Tuesday . That’s means we’re giving you an extra Newsletter: PCB Design! (7/30) The process of PCB design is always facing new complexities. Rules-based autorouting, chips with higher lead counts and higher speed interconnections are just a few of the challenges forcing PCB design software to keep pace. This newsletter updates you on the latest happenings in this area.

Analog & Power. (8/6) This newsletter content zeros in on the latest developments in analog and power technologies including DC-DC converters, AC-DC converters, power supplies, op amps, batteries and more.

Microcontroller Watch (8/13) This newsletter keeps you up-to-date on latest microcontroller news. In this section, we examine the microcontrollers along with their associated tools and support products.

IoT Technology Focus. (8/20) Covers what’s happening with Internet-of-Things (IoT) technology–-from devices to gateway networks to cloud architectures. This newsletter tackles news and trends about the products and technologies needed to build IoT implementations and devices.

Tuesday’s Newsletter: IoT Tech Focus

Coming to your inbox tomorrow: Circuit Cellar’s IoT Technology Focus newsletter. Tomorrow’s newsletter covers what’s happening with Internet-of-Things (IoT) technology–-from devices to gateway networks to cloud architectures. This newsletter tackles news and trends about the products and technologies needed to build IoT implementations and devices.

Bonus: We’ve added Drawings for Free Stuff to our weekly newsletters. Make sure you’ve subscribed to the newsletter so you can participate

Already a Circuit Cellar Newsletter subscriber? Great!
You’ll get your IoT Technology Focus newsletter issue tomorrow.

Not a Circuit Cellar Newsletter subscriber?
Don’t be left out! Sign up now:

Our weekly Circuit Cellar Newsletter will switch its theme each week, so look for these in upcoming weeks:

Embedded Boards.(7/23) The focus here is on both standard and non-standard embedded computer boards that ease prototyping efforts and let you smoothly scale up to production volumes.

Analog & Power. (8/6) This newsletter content zeros in on the latest developments in analog and power technologies including DC-DC converters, AC-DC converters, power supplies, op amps, batteries and more.

July has a 5th Tuesday . That’s means we’re giving you an extra Newsletter: PCB Design! (7/30) The process of PCB design is always facing new complexities. Rules-based autorouting, chips with higher lead counts and higher speed interconnections are just a few of the challenges forcing PCB design software to keep pace. This newsletter updates you on the latest happenings in this area.

Microcontroller Watch (8/13) This newsletter keeps you up-to-date on latest microcontroller news. In this section, we examine the microcontrollers along with their associated tools and support products.