Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation Pololu Maestro Servo Controller User’s Guide https://www.pololu.
Pololu Maestro Servo Controller User’s Guide 1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . 1.a. Micro Maestro Pinout and Components . . . . . . 1.b. Mini Maestro Pinout and Components . . . . . . 1.c. Indicator LEDs . . . . . . . . . . . . . . . . . . . 1.d. Supported Operating Systems . . . . . . . . . . 2. Contacting Pololu . . . . . . . . . . . . . . . . . . . . . 3. Getting Started . . . . . . . . . . . . . . . . . . . . . . 3.a. Installing Windows Drivers and Software . . . . . 3.b.
Pololu Maestro Servo Controller User’s Guide 7.a. Powering the Maestro . . . . . . . . 7.b. Attaching Servos and Peripherals . . 7.c. Connecting to a Microcontroller . . . 8. Writing PC Software to Control the Maestro 9. Maestro Settings Limitations . . . . . . . . 10. Related Resources . . . . . . . . . . . . © 2001–2017 Pololu Corporation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation 1. Overview The Maestros are Pololu’s second-generation family of USB servo controllers. The Maestro family consists of four controllers, each available fully assembled or as a partial kit: • Micro Maestro 6 [https://www.pololu.com/ product/1350] • Mini Maestro 12 [https://www.pololu.com/ product/1352] • Mini Maestro 18 [https://www.pololu.com/product/1354] • Mini Maestro 24 [https://www.pololu.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation A free configuration and control program is available for Windows and Linux (see Section 4), making it simple to configure and test the board over USB, create sequences of servo movements for animatronics or walking robots, and write, step through, and run scripts stored in the servo controller.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation Features • Three control methods: USB, TTL (5 V) serial, and internal scripting • 0.25μs output pulse width resolution (corresponds to approximately 0.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation • Free configuration and control application for Windows and Linux makes it easy to: ◦ Configure and test your controller ◦ Create, run, and save sequences of servo movements for animatronics and walking robots ◦ Write, step through, and run scripts stored in the servo controller The Status tab in the Maestro Control Center.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation Maestro Comparison Table Micro Maestro Mini Maestro 12 Mini Maestro 18 Mini Maestro 24 Channels: 6 12 18 24 Analog input channels: 6 12 12 12 Digital input channels: 0 0 6 12 Width: 0.85" (2.16 cm) 1.10" (2.79 cm) 1.10" (2.79 cm) 1.10" (2.79 cm) Length: 1.20" (3.05 cm) 1.42" (3.61 cm) 1.80" (4.57 cm) 2.30" (5.84 cm) Weight(1): 3.0 g 4.2 g 4.9 g 6.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation Application Examples • Serial servo controller for multi-servo projects (e.g. robot arms, animatronics, fun-house displays) based on microcontroller boards such as the BASIC Stamp, Orangutan robot controllers [https://www.pololu.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation Micro Maestro 6-channel USB servo controller (fully assembled) labeled top view. Note: This section applies to the Micro Maestro servo controller. Please see Section 1.b for Mini Maestro pinout and component information. The Pololu Micro Maestro 6-channel servo controller can connect to a computer’s USB port via a USB A to mini-B cable [https://www.pololu.com/product/130] (not included).
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation The processor and the servos can have separate power supplies. Processor power must come either from USB or from an external 5–16V power supply connected to the VIN and GND inputs. It is safe to have an external power supply connected at the same time that USB is connected; in such cases the processor will be powered from the external supply.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation serial interface, see Section 5.a. Note that the Maestro will probably be able to receive 3.3V TTL serial bytes, but it is not guaranteed to read 3.3V as high on the RX pin, so you should boost 3.3V TTL serial signals to above 4V if you want to ensure reliable operation. The TX line transmits non-inverted TTL (0–5 V) serial bytes.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation 1.b. Mini Maestro Pinout and Components Mini Maestro 12-channel USB servo controller (fully assembled) labeled top view. Mini Maestro 18-channel USB servo controller (fully assembled) labeled top view. 1.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation Mini Maestro 24-channel USB servo controller (fully assembled) labeled top view. Note: This section applies to the Mini Maestro 12, 18, and 24 servo controllers. Please see Section 1.a for Micro Maestro pinout and component information. The Pololu Mini Maestro 12-,18-, and 24-channel servo controllers can connect to a computer’s USB port via a USB A to mini-B cable [https://www.pololu.com/product/130] (not included).
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation The processor and the servos can have separate power supplies. Processor power must come either from USB or from an external 5–16V power supply connected to the VIN and GND inputs on the left side of the board. It is safe to have an external power supply connected at the same time that USB is connected; in that case the processor will be powered from the external supply.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation The signal lines (0, 1, 2, …) are used for sending pulses to servos, controlling digital outputs, and measuring voltages. The total current limit (in or out) for these pins is 200 mA, but when using the on-board regulator the current out is limited to 50 mA (see above.) The RX line is used to receive non-inverted TTL (0–5 V) serial bytes, such as those from microcontroller UARTs.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation Bottom view with dimensions (in inches) of Pololu Micro and Mini Maestro servo controllers. The dimensions of the Mini Maestro PCBs are shown in the picture above, along with the Micro Maestro for comparison. The mounting holes have a diameter of 0.086″and are intended for #2 or M2 screws. The vertical and horizontal distances between the two mounting holes are as follows: 1.2″ and 0.5″ for the Mini Maestro 12, 1.58″ and 0.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation proportional to the servo period (the amount of time between pulses on a single channel); with a period of 20 ms the flashing occurs approximately once per second.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation 2. Contacting Pololu You can check the product page of your particular Maestro model for additional information. We would be delighted to hear from you about any of your projects and about your experience with the Maestro. You can contact us [https://www.pololu.com/contact] directly or post on our forum [http://forum.pololu.com/].
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation 3. Getting Started 3.a. Installing Windows Drivers and Software If you are using Windows XP, you will need to have Service Pack 3 [https://technet.microsoft.com/en-us/windows/windows-xp-service-pack-3.aspx] installed before installing the drivers for the Maestro. See below for details. Before you connect your Maestro to a computer running Microsoft Windows, you should install its drivers: 1.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation Windows 10, Windows 8, Windows 7, and Windows Vista users: Your computer should now automatically install the necessary drivers when you connect a Maestro. No further action from you is required. Windows XP users: Follow steps 5–9 for each new Maestro you connect to your computer. 5. Connect the device to your computer’s USB port.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation 8. Windows XP will warn you again that the driver has not been tested by Microsoft and recommend that you stop the installation. Click “Continue Anyway”. 9. When you have finished the “Found New Hardware Wizard”, click “Finish”. After that, another wizard will pop up. You will see a total of three wizards when plugging in the Maestro. Follow steps 6-9 for each wizard. 3.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation After installing the drivers and plugging the Maestro in via USB, if you go to your computer’s Device Manager, you should see three entries for the Maestro that look like what is shown below: 3.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation Windows 7 device manager showing the Micro Maestro 6-channel USB servo controller. Windows XP device manager showing the Micro Maestro 6-channel USB servo controller. COM ports After installing the drivers, if you go to your computer’s Device Manager and expand the “Ports (COM & LPT)” list, you should see two COM ports for the Maestro: the Command Port and the TTL Port.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation You might see that the COM ports are named “USB Serial Device” in the Device Manager instead of having descriptive names. This can happen if you are using Windows 10 or later and you plugged the Maestro into your computer before installing our drivers for it. In that case, Windows will set up your Maestro using the default Windows serial driver (usbser.inf), and it will display “USB Serial Device” as the name for each port.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation The Maestro Control Center running in Ubuntu Linux. You can download the Maestro Control Center and the Maestro command-line utility (UscCmd) for Linux here: • Maestro Servo Controller Linux Software linux-150116.tar.gz?file_id=0J315] [https://www.pololu.com/file/download/maestro- (124k gz) Unzip the tar/gzip archive by running “tar -xzvf” followed by the name of the file. After following the instructions in README.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation with are described below. Default Settings • The serial mode is “UART, detect baud rate”; after you send the 0xAA baud rate indication byte, the Maestro will accept TTL-level serial commands on the RX line. • The Pololu Protocol device number is 12, the Mini SSC offset is 0, and serial timeout and CRC are disabled. • All channels are configured as servos, with a minimum pulse with of 992 μs and a maximum pulse width of 2000 μs.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation 4. Using the Maestro Control Center The Maestro’s USB interface provides access to all configuration options as well as support for realtime control, feedback, and debugging. The Maestro Control Center is a graphical tool that makes it easy for you to use the USB interface; for almost any project, you will want to start by using the control center to set up and test your Maestro.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation reached its target. For more precise control, a target value may also be entered directly into the “Target” input box. The slider is automatically scaled to match the minimum and maximum values specified in the Channel Settings tab, which is described in Section 4.b. For a channel configured as input, the slider, green ball, “Target”, and “Position” display the current value of the input. There is no control available for inputs.
Pololu Maestro Servo Controller User’s Guide Period range © 2001–2017 Pololu Corporation Period On-time resolution resolution 1–1024 4 1 1025–4096 16 4 4097–16384 64 16 The special periods 1024, 4096, and 16384 are not recommended, since 100% duty cycle is not available at these values. If the on time is set equal to the period at one of the special values, the duty cycle will be 0% (a low output). The periods 1020 (47.1 kHz), 4080 (11.7 kHz), and 16320 (2.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation A separate row of controls is displayed for each of the Maestro’s channels: Name. Each of the channels may be assigned a name, for your convenience. Channel names are not stored on the device but instead in the system registry on your computer; if you want to use your Maestro on a different computer without losing the names, save a settings file on the old computer and load it into the Maestro with the new one. Mode.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation • Ignore specifies that the servo should initially be off, but that its value should not change on error. • Go to specifies a default position for the servo. The servo target will be set to this position on start-up or when an error occurs. Speed. This option specifies the speed of the servo in units of 0.25 μs / (10 ms). For example, with a speed of 4, the position will change by at most 1 μs per 10 ms, or 100.00 μs/s.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation to make fewer servos available are to allow a longer maximum pulse length or a shorter period. Period multiplier is an advanced option for the Mini Maestro 12, 18, and 24 that allows a larger period (lower pulse rate) on some of the channels. For example, if you select a period of 3 and a multiplier of 6, you can have some servos run at 3 ms (333 Hz) and the others at 18 ms (55 Hz).
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation The Sequence tab in the Maestro Control Center. The Sequence tab allows simple motion sequences to be created and played back on the Maestro. A sequence is simply a list of “frames” specifying the positions of each of the servos and a duration (in milliseconds) for each frame. Sequences are stored in the registry of the computer where the sequence was created. Sequences can be copied to the script, which is saved on the Maestro.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation The Save Over Current Frame button overwrites the selected frame(s) with the current target values from the Maestro. If the Play in a loop checkbox is checked, sequence playback will loop back to the beginning of the sequence whenever it reaches the end. The Sequence dropdown box along with the Rename, Delete, and New Sequence buttons allow you to create and manage multiple sequences.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation • Ctrl+C: Copy selected frames. • Ctrl+V or Shift+Insert: Paste/insert frames from clipboard. • Ctrl+X: Cut selected frames. • Ctrl+Up: Move selected frames up. • Ctrl+Down: Move selected frames down. • Del: Delete selected frames. 4.d. Entering a Script The Script tab in the Maestro Control Center. The Script tab is where you enter a script to be loaded into the Maestro.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation the Maestro, one instruction at a time, until a QUIT instruction is reached or an error occurs. In many cases it will be useful to use a loop of some kind to cause a script to run forever. While the script is running, the red “Stop Script” button will be available, and the small pink triangle will jump around your source code, showing you the instruction that is currently being executed.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation The Errors tab in the Maestro Control Center. The Errors tab indicates problems that the Maestro has detected while running, either communications errors or errors generated by bugs in a script. Each error corresponds to a bit in the two-byte error register. The red LED will be on as long as any of the bits in the error register are set to 1 (it can also be turned on by the led_on script command).
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation • Serial overrun error (bit 1) A hardware-level error that occurs when the UART’s internal buffer fills up. This should not occur during normal operation. • Serial buffer full (bit 2) A firmware-level error that occurs when the firmware’s buffer for bytes received on the RX line is full and a byte from RX has been lost as a result. This error should not occur during normal operation.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation Performance Flags The errors tab also shows which performance flags have been set. This feature only applies to the Mini Maestro 12, 18, and 24. The performance flags indicate that the processor missed a deadline for performing a servo control task, and as a result the Maestro’s servo control got slowed down in some way.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation connecting to a Maestro, and looking at the firmware version number which is displayed in the upper left corner next to the “Connected to” drop-down box. If you do not already have the latest version (1.03), you can upgrade by following the instructions below: 1. Save the settings stored on your Maestro using the “Save settings file…” option in the File menu.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation you should follow steps 6–8 from Section 3.a to get the bootloader’s driver working. 9. Once the Maestro is in bootloader mode and the bootloader’s drivers are properly installed, the green LED should be blinking in a double heart-beat pattern, and there should be an entry for the bootloader in the “Ports (COM & LPT)” list of your computer’s Device Manager. 10.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation 1. To perform a hard bootloader reset, first make sure the Maestro is powered off. It is best if you can just disconnect everything from it. 2. Using a screwdriver, a small piece of wire, or some other conductive tool, short the two exposed bootloader pads together. The pads are shown in the pictures below: Bootloader pads for the Micro Maestro 6-Channel USB Servo Controller.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation can stop shorting together the pads and retry the firmware upgrade procedure in Section 4.f starting at step 7. 4.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation 5. Serial Interface 5.a. Serial Settings The Maestro has three different serial interfaces. First, it has the TX and RX lines, which allow the Maestro to send and receive non-inverted, TTL (0 – 5 V) serial bytes (Section 5.b). Secondly, the Maestro shows up as two virtual serial ports on a computer if it is connected via USB. One of these ports is called the Command Port and the other is called the TTL port.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation The Serial Settings tab in the Maestro Control Center. The Maestro can be configured to be in one of three basic serial modes: USB Dual Port: In this mode, the Command Port can be used to send commands to the Maestro and receive responses from it. The baud rate you set in your terminal program when opening the Command Port is irrelevant. The TTL Port can be used to send bytes on the TX line and receive bytes on the RX line.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation opening the TTL Port determines the baud rate used to receive and send bytes on RX and TX. This allows your computer to control the Maestro and simultaneously use the RX and TX lines as a general purpose serial port that can communicate with other types of TTL serial devices. USB Chained: In this mode, the Command Port is used to both transmit bytes on the TX line and send commands to the Maestro.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation Mini SSC offset: This parameter determines which servo numbers the device will respond to in the Mini SSC protocol (see Section 5.e). Timeout: This parameter specifies the duration before which a Serial timeout error will occur. This error can be used as a safety measure to ensure that your servos and digital outputs go back to their default states whenever the software sending commands to the Maestro stops working.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation Diagram of a non-inverted TTL serial byte. A non-inverted TTL serial line has a default (non-active) state of high. A transmitted byte begins with a single low “start bit”, followed by the bits of the byte, least-significant bit (LSB) first. Logical ones are transmitted as high (VCC) and logical zeros are transmitted as low (0 V), which is why this format is referred to as “non-inverted” serial.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation 254. The Maestro responds to three sub-protocols: Compact Protocol This is the simpler and more compact of the two protocols; it is the protocol you should use if your Maestro is the only device connected to your serial line.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation we could send the following byte sequence: in hex: 0xAA, 0x0C, 0x04, 0x00, 0x70, 0x2E in decimal: 170, 12, 4, 0, 112, 46 Note that 0x04 is the command 0x84 with its most significant bit cleared. Mini SSC Protocol The Maestro also responds to the protocol used by the Mini SSC servo controller. This protocol allows you to control up to 254 different servos by chaining multiple servo controllers together.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation CRC for that packet. If this CRC byte is incorrect, the Maestro will set the Serial CRC error bit in the error register and ignore the command. The Maestro does not append a CRC byte to the data it transmits in response to serial commands. A detailed account of how cyclic redundancy checking works is beyond the scope of this document, but you can find a wealth of information using Wikipedia [http://en.wikipedia.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation Steps 1 & 2 (write as binary, least significant bit first, add 7 zeros to the end of the message): CRC-7 Polynomial = [1 0 0 0 1 0 0 1] message = [1 1 0 0 0 0 0 1] [1 0 0 0 0 0 0 0] 0 0 0 0 0 0 0 Steps 3, 4, & 5: _______________________________________________ 1 0 0 0 1 0 0 1 ) 1 1 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 XOR 1 0 0 0 1 0 0 1 | | | | | | | | | | | | | | | --------------- | | | | | | | | | | | | | | | 1 0 0 1 0 0
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation in binary: 10000100, 00000010, 01110000, 00101110 in hex: 0x84, 0x02, 0x70, 0x2E in decimal: 132, 2, 112, 46 Here is some example C code that will generate the correct serial bytes, given an integer “channel” that holds the channel number, an integer “target” that holds the desired target (in units of quarter microseconds if this is a servo channel) and an array called serialBytes: 1 2 3 4 serialBytes[0] serialBytes[1] serialByte
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation bytes contain the target values for each of the channels, in order by channel number, in the same format as the Set Target command above.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation At the minimum acceleration setting of 1, the servo output takes about 3 seconds to move smoothly from a target of 1 ms to a target of 2 ms. The acceleration setting has no effect on channels configured as inputs or digital outputs.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation the Position box in the Status tab of the Maestro Control Center.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation Pololu protocol: 0xAA, device number, 0x22 This command sends all servos and outputs to their home positions, just as if an error had occurred. For servos and outputs set to “Ignore”, the position will be unchanged. Note: For servos marked “Off”, if you execute a Set Target command immediately after Go Home, it will appear that the servo is not obeying speed and acceleration limits.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation Get Script Status Compact protocol: 0xAE Pololu protocol: 0xAA, device number, 0x2E Response: 0x00 if the script is running, 0x01 if the script is stopped This command responds with a single byte, either 0 or 1, to indicate whether the script is running (0) or stopped (1).
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation The Mini Maestro 12, 18, and 24 have a special input called TXIN that eliminates the need for an external AND gate (the AND gate is built in to the Maestro.) To make a chain of devices using the TXIN input, connect them like this: Daisy chaining serial devices that have a TXIN input. Using a PC and a Maestro together as the master device The Maestro can enable a personal computer to be the master device.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation Whenever connecting devices, remember to wire the grounds together, and ensure that each device is properly powered. Unpowered devices with a TTL serial port can turn on or partially on, drawing power from the serial line, which means that extra care must be taken when turning power off and on to reset the devices.
Pololu Maestro Servo Controller User’s Guide 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 © 2001–2017 Pololu Corporation // Uses POSIX functions to send and receive data from a Maestro. // NOTE: The Maestro's serial mode must be set to "USB Dual Port". // NOTE: You must change the 'const char * device' line below. ? #include #include
Pololu Maestro Servo Controller User’s Guide 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 © 2001–2017 Pololu Corporation _setmode(fd, _O_BINARY); #else struct termios options; tcgetattr(fd, &options); options.c_iflag &= ~(INLCR | IGNCR | ICRNL | IXON | IXOFF); options.c_oflag &= ~(ONLCR | OCRNL); options.c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN); tcsetattr(fd, TCSANOW, &options); #endif int position = maestroGetPosition(fd, 0); printf("Current position is %d.
Pololu Maestro Servo Controller User’s Guide 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 © 2001–2017 Pololu Corporation #include<18f4550.
Pololu Maestro Servo Controller User’s Guide } © 2001–2017 Pololu Corporation printf "\\x$(printf "%x" $1)" stty raw -F $DEVICE { byte 0x84 byte $CHANNEL byte $((TARGET & 0x7F)) byte $((TARGET >> 7 & 0x7F)) } > $DEVICE This script can also be run on Windows, but since Windows does not have bash installed by default it is easier to use UscCmd. 5.h.5. Arduino library We provide an Arduino library [https://github.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation Example setup showing how to control a Maestro with an A-Star Prime or Arduino-compatible board. 5.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation 6. The Maestro Scripting Language A script is a sequence of commands that is executed by the Maestro. Commands can set servo targets, speeds, and accelerations, retrieve input values, and perform mathematical computations. Basic control structures – looping and conditionals – are available for use in making complicated scripts.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation Note that the PLUS command always decreases the size of the stack by one. It is up to you to make sure that you have enough values on the stack to complete the commands you want to run! Consider a more complicated example: suppose we want to compute the value of (1 – 3) × 4, using the MINUS and MULTIPLY commands. The way to write this computation as a script is “1 3 MINUS 4 TIMES”.
Pololu Maestro Servo Controller User’s Guide 1 2 3 4 5 6 7 8 9 10 10 # start with a 10 on the begin dup # copy the number while # jump to the end 8000 1 servo 500 delay 4000 1 servo 500 delay 1 minus # subtract 1 from repeat © 2001–2017 Pololu Corporation stack ? on the stack - the copy will be consumed by WHILE if the count reaches 0 the number of times remaining Note that BEGIN…WHILE…REPEAT loops are similar to the while loops of many other languages.
Pololu Maestro Servo Controller User’s Guide 1 2 3 4 sub neutral 6000 1 servo 6000 2 servo return © 2001–2017 Pololu Corporation ? Then, whenever you want send these two servos back to neutral, you can just use “neutral” as a command. More advanced subroutines take values off of the stack. For example, the subroutine 1 2 3 sub set_servos 2 servo 1 servo return ? will set channel 2 to the value on the top of the stack and channel 1 to the next value.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation Keywords keyword stack effect description BEGIN none marks the beginning of a loop ENDIF none ends a conditional block IF…ENDIF ELSE none begins the alternative block in IF…ELSE…ENDIF GOTO label none goes to the label label (define it with label:) IF -1 enters the conditional block if the argument is true (non-zero) in IF…ENDIF or IF…ELSE…ENDIF REPEAT none marks the end of a loop SUB name none defines a subr
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation Stack commands command stack effect DEPTH +1 gets the number of numbers on the stack DROP -1 removes the top number from the stack DUP +1 duplicates the top number OVER +1 duplicates the number directly below the top, copying it onto the top PICK -1,+1 takes a number n between 0 and 63, then puts the nth number below the top onto the stack (0 PICK is equivalent to DUP) SWAP a,b → swaps the top two numbers b,a RO
Pololu Maestro Servo Controller User’s Guide command BITWISE_NOT C equivalent ~ © 2001–2017 Pololu Corporation description inverts all of the bits in its argument LOGICAL_NOT ! replaces true by false, false by true NEGATE – replaces x by -x POSITIVE none true if and only if the argument is greater than zero NEGATIVE none true if and only if the argument is less than zero NONZERO none true (1) if and only if the argument is true (non-zero) Mathematical commands (binary) These commands take
Pololu Maestro Servo Controller User’s Guide command C equivalent © 2001–2017 Pololu Corporation description BITWISE_AND & applies the boolean AND function to corresponding bits of the arguments BITWISE_OR | applies the boolean OR function to corresponding bits of the arguments BITWISE_XOR ^ applies the boolean XOR function to corresponding bits of the arguments DIVIDE / divides the arguments EQUALS == true if and only if the arguments are equal GREATER_THAN > true if and only if the fi
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation Servo, LED, and other output commands command stack effect description SPEED -2 sets the speed of the channel specified by the top element to the value in the second element (see Section 4.b) ACCELERATION -2 sets the acceleration of the channel specified by the top element to the value in the second element (see Section 4.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation It is a good idea to try stepping through this script before doing anything further with scripts on the Maestro. In particular, pay attention to how the command “100” puts the number 100 on the stack, and the DELAY command consumes that number.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation the loop. At this rate, we could store up to 92 servo positions in the 1024-byte memory of the Micro Maestro, or 744 servo positions in the 8192-byte memory of the Mini Maestros. To get the most out of the limited memory, there are a variety of ways to compress the program. Most important is to make use of subroutines.
Pololu Maestro Servo Controller User’s Guide 1 2 3 4 5 6 7 8 9 10 11 12 © 2001–2017 Pololu Corporation # Move servo 0 to five different positions, in a loop.
Pololu Maestro Servo Controller User’s Guide 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 © 2001–2017 Pololu Corporation # This example uses speed and acceleration to make a smooth # motion back and forth between 1 and 2 ms. 3 0 acceleration 30 0 speed ? begin 4000 0 servo # set servo 0 to 1.00 ms moving_wait 8000 0 servo # 2.
Pololu Maestro Servo Controller User’s Guide 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 © 2001–2017 Pololu Corporation # Set the servo to 4000, 6000, or 8000 depending on an analog input.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation capable channels (channels 0–11). The inputs on the other channels are digital. Using a button or switch to control servos It is possible to connect a button or switch to a Maestro and detect the state of the button in your script. The script below moves a servo through a predefined sequence of movements, advancing to the next step each time the button is pushed. It uses channel 0 for the button and channel 1 for the servo.
Pololu Maestro Servo Controller User’s Guide 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 goto main_loop © 2001–2017 Pololu Corporation # Run the main loop when the script starts (see below). ? # This subroutine returns 1 if the button is pressed, 0 otherwise.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation Just like the sequencing examples above, the script steps through a sequence of frames, but instead of a timed delay between frames, this example waits for a button press. The WAIT_FOR_BUTTON_PRESS subroutine can be used in a variety of different scripts, whenever you want to wait for a button press. You could also expand this example to allow multiple buttons, continuous motion, or a variety of other types of button control.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation Please note that this script does not do multi-tasking. If a sequence is running, the script will not detect other button presses until the sequence is done. It is possible to make the buttons operate independently, but the script would need to be much more complicated. Depending on how skilled you are at writing scripts, you might prefer to use multiple Maestros instead.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation The digital output feature of the Maestro is capable of controlling anything from simple circuits to intelligent devices such as the ShiftBrite LED Modules [https://www.pololu.com/ product/1222] and ShiftBar LED Controllers [https://www.pololu.com/product/1242], which use a simple synchronous serial protocol.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation Note that we use 0 to set the output low and 8000 to set the output high. These are reasonable choices, but any value from 0 to 5999 could be used for low, and anything from 6000 to 32767 could be used for high, if desired. Serial output (Mini Maestro 12, 18, and 24 only) On the Mini Maestro 12, 18, and 24, a script can be used to send serial data out on the TTL-level serial port (TX).
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation Number of subroutines: This is the number of different subroutines you are allowed to have. The first 128 subroutines defined in your script are special: these subroutines can be started using a serial or native USB command, and each call from within your script requires only one byte of script space. The Micro Maestro only supports having up to 128 subroutines.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation 7. Wiring Examples This section contains example wiring configurations for the Maestro that demonstrate the different ways it can be connected to your project. Although many of the pictures only show the Micro Maestro, the information in this section applies to all Maestros (unless otherwise noted). 7.a. Powering the Maestro There are several ways to power your Maestro’s processor and the servos it is controlling.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation If you connect a power supply to the servo power terminal and connect another power supply to GND/ VIN, then the Maestro’s processor will be powered from the VIN supply while the servos are powered from their own supply. The VIN supply must be within 5–16 V and be capable of supplying at least 30 mA to the Micro Maestro or 50 mA to the Mini Maestro.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation 7.b. Attaching Servos and Peripherals On the Maestro, any of the channels can be used as RC servo pulse output, as an analog/digital input, or as a digital output. This allows the Maestro to control servos, read button presses, read potentiometer positions, drive LEDs, and more. The channels can be controlled from the user script within the Maestro or externally over TTL-level serial or USB.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation 24-channel servo controller and enable its internal pull-up resistor in Channel Settings tab of the Maestro Control Center. You can test your input by toggling the button/switch and verifying that the “Position” variable as shown in the Status tab of the Maestro Control Center reflects the state of your button/switch: it should be close to 255.75 when the button/switch is inactive and close to 0 when it is active.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation To connect an LED to the Maestro, you should first decide which channel you would like to use. In the Maestro Control Center, under the Channel Settings tab, change that channel to Output mode and click “Apply Settings”. Next, connect the cathode of the LED to GND (any ground pad on the Maestro will suffice because they are all connected).
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation Maestro. If you want your microcontroller to have the ability to detect errors from the Maestro using a digital input instead of the serial command, or you want to receive direct feedback from the user script, then connect the ERR line of the Maestro to any general-purpose I/O line of the microcontroller. The ERR line is only available on the Mini Maestro 12-, 18-, and 24-channel servo controllers. See Section 1.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation 8. Writing PC Software to Control the Maestro There are two ways to write PC software to control the Maestro: the native USB interface and the virtual serial port. The native USB interface provides more features than the serial port, such as the ability to change configuration parameters and select the Maestro by its serial number. Also, the USB interface allows you to recover more easily from temporary disconnections.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation 9. Maestro Settings Limitations Mini Maestro serial baud rate limitations On the Mini Maestro 12, 18, and 24, the following baud rates should not be exceeded, or the processor may become overloaded, causing degraded performance. 10–100 Hz 111–250 Hz Serial mode: UART/USB chained* Serial mode: Dual-port 200 kbps 115.2 kbps 333 Hz 115.2 kbps 115.2 kbps 57.6 kbps 57.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation On the Mini Maestro 12, 18, and 24, pulse rates of 200–333 Hz put restrictions on the servo pulse lengths. These restrictions apply to all servo channels, even if some are set to a lower pulse rate using the Period multiplier feature. The following tables show allowed minimum and maximum pulse lengths, in microseconds, for a variety of combinations of pulse rates and servo numbers.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation Allowed pulse ranges at 200 Hz: Servos Min Max 6 64 3000+ 12 64 3000+ 6/6 384/64 3000+ 18 64 3000+ 12/6 576/64 3000+ 24 24 64 2600 768 3000+ 18/6 768/64 3000+ 9.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation 10. Related Resources This section lists resources that might help you use the Maestro. Please note that these resources are of varying quality and most are not tested or supported by Pololu. Tutorials and example code • Sample Project: Simple Hexapod Walker [https://www.pololu.com/docs/0J42] • Obstacle avoider robot [http://forum.pololu.com/viewtopic.php?f=2&t=2756]: This robot features a Maestro as its main controller.
Pololu Maestro Servo Controller User’s Guide © 2001–2017 Pololu Corporation • PHP serial example code [http://forum.pololu.com/viewtopic.php?f=16&t=5951] • MATLAB serial example code [http://forum.pololu.com/ viewtopic.php?f=15&t=5090&p=24142#p24142] • LabVIEW VI for Micro Maestro [http://forum.pololu.com/viewtopic.php?f=23&t=4538] • libusc [https://github.
