Verification Of Operation

This page tells how to verify basic operation of the Magni robot. These tests can be used to regression test hardware and firmware changes or new production boards installed in the Magni robot.

Also included is a discussion on the evaluation of the the state of your batteries.

There is a main board we call the Motor Control Board or MCB. This is sometimes called Main Control Board as well.

There is a host linux computer which is the Raspberry Pi single board computer at this time and it plugs into the MCB as well as is powered from the MCB supplies.

If you have Magni Silver then the robot will have a Sonar Board which will have a few blue LEDs on top that will be helpful but not required to do these tests.

Powering Up The Magni ROBOT

Before we get going on the tests a quick word on the two power switches on the Switch Board that plugs into the main board may be of value.

Both switches must be in the OUT position for full robot operation.

  • The black switch to the left as you look at the robot from the front is the Main Power button. To enable this the switch must be out and not pressed in. When the main power is enabled the blue led on the switch board is on.
  • The red switch to the right is the ESTOP Switch and it is easiest to think of this as the power for the motors. To power up the wheel motors this switch must also be in the OUT position and the red led on the switch board will light when power is enabled.

As of later in 2019 switch boards started to have two connectors so that users could have their own switches on their product. If you have a current switch board then there will be a white connector just behind the ESTOP switch to the right which MUST BE SHORTED OUT for motor power to work. We ship this version switch board with a jumper in that jack but it can get lost.

Evaluating The Batteries Of The Robot

One of the most common issues with the robot is that the batteries are not fully charged due to lack of charging or because they have degraded to a point where they no longer hold charge as well as when they were new. This section is here because all too often the real problems we see in the field are due to degraded or poorly charged batteries.

Your batteries will degrade over time and loose their ability to hold as much charge as when they were new especially if they are accidentally over-discharged many times.

Unlike most cars, the Magni robot does have hardware that will shut off the usage of the batteries when the battery voltage gets VERY low but there is still some degradation every time you let the magni low voltage cutoff be the method of shutting off the product. Shutdown and turn off your robot then charge it when you leave it overnight.

We urge customers to be aware of the need to do battery charging and more recent changes show battery voltage and if it is low on our OLED display to try to make this easier to know.

Here are some ways to get a rough idea of if your batteries are ‘degraded’.

  • Fully charge the robot overnight or for many hours in the off state till the charger led goes to green. If your charger led never goes to green for a very long charge such as over 10 hours, the batteries are in need of replacement (or the charger is bad).
  • After a full charge let the robot sit with power off for over an hour and measure the battery voltage if you have a voltmeter. If this voltage is below 25.4 volts the batteries are in some weakened state but likely usable. If the voltage is below 24.5 volts your batteries are in need of replacement.
  • If above are ok, turn on the robot as well as the motor power (both switches on) and let the robot sit this way for 30 minutes to reach a stable mild load state. If at the end of this time the voltage is below 25 volts your batteries are weak but just how weak is difficult to judge in this simple test. If the voltage is 24V or below you most certainly have batteries in need of replacement. This test is easier if you have the little OLED display and very current software that shows the battery voltage on the OLED display.

Part 1: MCB Hardware Level Verification

1.1 Power Supply And Status LED Indications

There is a line of 4 power supply indicator LEDs and a ‘STAT’ or status led that are in a row to the lower left of the board. The 4 power supply leds should all be on and the status LED default state is to be on almost all the time but have very brief ‘dropout’blink that form a blink every 4 to 6 seconds. See the firmware_upgrade page for the expected blink rates of released firmware.

Revision 5.0 main control boards and after have the leds in a horizontal line with the ‘STAT’ led to the right. On version 4.9 and other early production units the LEDs are vertical with ‘STAT’ at the top of the line of leds.

If the ‘STAT’ led is off or does not blink there is something wrong with the onboard microprocessor subsystem on the main board.

Starting with version 5.2 of the main control board, MCB, there is an onboard 3.3V power supply and a blue led up near the top and a bit below the large white ‘MAIN’ 4-pin power jack. This led has the label 3.3V and must be on.

1.2 The Electronic Circuit Breakers And Power Indicators

Starting with main board version 5.0 there are two LEDs that indicate the ECB circuit involved is active and passing power. The switch board switches must be able to control the two ECB circuits as discussed below.

On the lower left of the main board a blue LED will be ON if the Main ECB has been enabled due to the main power switch being set to the out position. The main switch is black and is to the left on the little switch board.

On the lower right of the main board a blue LED will be ON if the ESTOP switch is set to the out position AND the main power switch is also in the out position.

1.3 ESTOP Switch Motor Power Safety Overrides

The ESTOP and motor initial state tests require a fully functional robot. Some of these tests appear later in section 3 as well as here because these test sections are used for different types of verifications.

  • This first test can be done without the host CPU installed or with it installed. Start with the robot powered down and the ‘ESTOP’ switch in the ‘out’ position and the black main power switch pushed in so the Magni is totally off. Then push the black main power switch which will turn on main power. At this point the main power switch will be in the ‘out’ position. VERIFY both the blue and red leds on the switchboard are on AND the blue led on bottom right of rev 5.1 MCB or later is on AND that the main power and status leds are all on located on the left middle of the MCB VERIFY that there is no jump in motors or if movement happens it is less than one cm. VERIFY that both motors are in the locked state strongly resisting movement.

  • With a host CPU, Raspberry Pi, installed do same as above and wait for motor node to be fully started which takes up to 2 minutes but is often faster. On rev 5.2 MCB you can see the motor node is active when both the ‘SIN’ and ‘SOUT’ leds near center top of the MCB are both blinking quickly. VERIFY that the robot does not jump or move more than 1 cm as as the robot fully starts. VERIFY that the Wheels did not jump in movements as we started the robot.

  • Push in the red ESTOP switch. VERIFY the ESTOP red LED goes off on the switch board and also verify the blue led on bottom right of rev 5.1 and later MCB boards fades within 5 or so seconds whih is the ‘Motor Power’ led. VERIFY the motors can be turned without a lot of force (One direction has mild resistance and the other is fairly free to move and this is natural and expected.

  • If you have an MCB rev 5.1 or later and v35 or later firmware this test must work. While ESTOP is active and motor power is off turn both wheels by a half turn or so in either direction. After the wheels have been turned press ESTOP so that the switch is OUT again. VERIFY there was little to no movement in the wheels

For an even more complete set of ESTOP tests you may want to also view the motion tests in section 3 of this document.

Part 2: Basic Host To MCB Tests

2.1 Serial Communications LEDS

Starting with version 5.2 of the main control board, MCB, there are two leds that show if serial communications are active between the host processor (Raspberry Pi) and the MCB. Both of these leds are located in the middle of the MCB and very high up near the white power jacks at the top of the PC board.

The lower blue LED is the SOUT led and will blink rapidly when the MCB processor is active even if there is no host processor. This LED shows the signal seen by the host processor so the level shifter must work for this to be seen.

The upper blue LED is the SIN led and will blink when the host processor is actively sending commands and queries to the MCB. This is the most important led to be blinking. It indicates of the ROS node called /motor_node is actively controlling the MCB. Note that depending on certain network conditions it may take up to a couple minutes for host motor_node to start communications with the MCB.

2.2 Wifi Verification

If no LAN cable is attached and if the robot has not been configured to look for a WiFi OR if no WiFi can be seen then the Magni software will create a HotSpot that you can connect to with your laptop.

There is a WIFI status led on the large MCB board if it is rev 5.2 later. The MCB WIFI led is located on the right middle height of the MCB. There is also this WIFI led on the optional sonar board however which does brief blinks to on at same rate. The table below shows WiFi status indications for the led on the MCB which is mostly on with short blinks off at rates shown in the table.

Blink Rate WiFi Status
2 per sec WiFi is being initialized after a startup or reboot
1 per sec WiFi is operating as an Access Point (AP) and ready to be connected to by a laptop or phone
1 per 2 sec WiFi has successfully connected to your own WiFi ssid setup already

Do these tests with no Lan cable plugged into the Magni host computer.

If you have Magni Silver with the Sonar board then as the robot is powered up the LED2 (right LED on Sonar board as seen from the front) will light with dim blue light. If you have a rev 5.2 MCB there will also be the WiFi led on the MCB but it goes off when the sonar board one goes on so they alternate.

After 6 or so seconds that LED on the sonar board will turn off. After about 16 or so seconds if WiFi is able to come up LED2 will start to blink brightly about once per second indicating that the WiFi HotSpot is up. We are working on enhancements to be available by mid 2020 which will indicate AP mode active or that the wifi specified by pifi utility is not available and perhaps more states on this led.

Starting with main control board version 5.2 there will also be a wifi led on the right visible from the front of the magni. This led is opposite from the sonar board led so it is off when the sonar board led is on and so on.

2.2.1 Connect To The Magni Hotspot

At this time if you have on your smartphone some sort of WiFi network scanner you will see a ubiquityrobotics WiFi with last 4 digits being a unique hex value.

You will also see this HotSpot show up on your laptop and will be able to connect. Read HERE for more.

Verify you can connect to the Magni using password ‘robotseverywhere’ and verify you can open a console using SSH.

2.2.2 Verify Magni Can Connect To Your Local Wifi

For this test you should follow the configuration page for pifi to configure your own network once you are connected using pifi commands available HERE .

2.3 Check Operation Using The /diagnostics ROS topic

When the robot is running quite a few pieces of diagnostic information can be viewed by looking at the ROS topic the motor node publishes. The diagnostic topic has other things besides the motor node so we filter it for firmware info in the example below for easy reading.

rostopic echo /diagnostics | grep -A 1  'Firmware [DV]'

You can view the full diagnostics output and find other info such as:

  • Battery Voltage key shows the battery level in DC volts
  • Motor Power key is True when the ESTOP is enabling wheel power
  • Firmware Version shows the main board firmware version
  • Firmware Date shows the date for the firmware
  • Firmware Options shows hardware options if enabled

In the raw /diagnostics output these things may also be useful for feedback to factory on some issues. For full output of /diagnostics do this.

rostopic echo /diagnostics

2.4 I2C Bus Devices

The I2C bus on the host CPU needs to be able to communicate to a few devices on the MCB. With recent software on newer MCB boards there is a small OLED display. If this display shows the expected text the I2C bus is working but you still need to see if other I2C devices are on the bus.

There is an I2C excpander at addr 0x20 and RealTime clock chip at address 0x6F. If there is a OLED display loaded on P2 it is at 0x3c. We should stop the motor node then run i2cdetect which is part of i2c-tools package.

sudo systemctl stop magni-base.service
sudo i2cdetect -y 1

The above command will output 8 lines each with 16 possible hex addresses. We want to note that it detected devices that are present on the I2C bus. The OLED display was optional prior to MCB rev 5.2. The table that follows shows likely addresses.

Device I2C Address Notes
SSD1306 OLED Display 0x3C Shipped starting on MCB Rev 5.2
PCF8574 0x20 IO port on MCB
MCP7940 RT Clock 0x6f RTC will show as UU addr
BNO055 Expander 0x28 Optional - Advanced Accel/Gyro IMU
PCF8572 Expander 0x21 Optional - IO port on IMU Expander
  • Because the MCP7940 is owned by the kernel the i2cdetect tool will show it at address 0x6F as UU. This indicates it was seen. If the kernel recognized the RTC properly there will be a /dev/rtc0 device for final confirmation.

  • Expander boards are optional small boards that sit under the OLED display and are not present from production MCB boards. They are special ordered and added later.

  • If there is a production issue where a PCF8574A was incorrectly loaded then you would see address 0x38. This is considered a misload in production.

After this test you may restart magni-base service

sudo systemctl start magni-base.service

Part 3: Basic Movement Tests:

This set of tests has the focus of verification of circuits and commands that are related to robot movement or the ESTOP safety feature.

3.1 ESTOP Switch Motor Power Safety Override

There is a more complete test in Part 1.3 earlier in this doc however this test is here to validate the way the ESTOP switch should impact movement by using a few simple tests.

  • Start with the red ‘ESTOP’ switch in the ‘out’ position and the black main power switch pushed in so the Magni is totally off. Then push the black main power switch so both main and motor power will be active and both switches are in the ‘out’ position. VERIFY that there is no jump in motors that the robot ideally did not move at all or if it did it only moved no more than one cm and that the motors are in the stopped state strongly resisting movement.

  • Wait for motor node to be fully started which can take some time. On rev 5.2 MCB you can see the motor node is active when both the ‘SIN’ and ‘SOUT’ leds near center top of the MCB are both blinking quickly. In certain network situations this may take longer than 2 minutes. VERIFY that the robot does not jump or move of if it does, it did not move more than 1 cm as the robot initialized.

  • Push in the red ESTOP switch so motor power is off. Rotate either or both wheels either direction for a half or more rotation by either pushing the robot or turning either wheel manually. VERIFY that when you then turn motor power back on with the red switch that the robot does not jump and the wheels did not rotate.

  • Put a block of wood or brick under the chassis in the front between the main motor wheels so no drive wheels touch the ground, just castors. Use some form of control to drive the robot forward or backward or rotate it so you can keep that movement going and the wheels keep moving the expected way. You can use joystick or teleop_twist_keyboard command such as rostopic pub -r 10 /cmd_vel geometry_msgs/Twist '{ linear: {x: 0.3} }' VERIFY that while this is going on you can turn off motor power and wheels stop. VERIFY that you can turn back on power and the wheels will start to move again at the same speed without any jerky or fast speedup catching up of any sort.

3.2 Distance and Low Speed Movement Tests:

Enter keyboard movement using:

rosrun teleop_twist_keyboard  

Press the ‘z’ key about 12 times until the ‘speed’ value shows about 0.15 meters per second; the ‘turn’ value will show about 0.3

At this point the robot will not move because when teleop is first entered it is in same state as if the ‘k’ was hit.

We need a second window open that we will call the ‘tf’ window; in that window type:

Also as setup have a second window open and in that type:

rosrun tf tf_echo odom base_link  

This command will continually update the robot position. There will be one line that shows the translation and 3 values that are for X,Y,Z in meters. The line will look like this if the robot was powered up in it’s current position:

Translation: [0.000, 0.000, 0.100]   at first where X and Y are 0.000.

Now we will do a few tests so make sure the robot has room to move forward about 1 meter and could have room to rotate fully. Because these tests are not precisely timed the distances and rotations will be only near the expected values.

  • Put a piece of tape or a coin on the floor beside the central hub of a front wheel to know where the robot started.

  • Press k key then use z or q until ‘speed’ value is near 0.15 MPS.

  • In the teleop window press the i letter key at a quick rate for 4 seconds. This should move the Magni about 0.5 - 0.6 meters forward which is about one spin of each wheel since one rotation is very near 0.64 meters.

  • Look at the ‘Translation’ line in the second tf window and the first of the 3 numbers is X and verify with a ruler that the translation is very close to the measured distance on the floor.

  • In the teleop window press the , (comma) key at a quick rate for 4 seconds. This should move the Magni backwards to about where it started.

  • Look at the ‘Translation’ line in the second tf window and the first of the 3 numbers is X and should have returned to near 0.0. Because of human timing there will be a small error.

  • Next press the j letter key at a quick rate for about 5 seconds so the Magni rotates a little more than 90 degrees to face left. The tf window will have the 3rd line that says ‘degrees’ where at this rotation the 3rd number should be near or just above 90 degrees to the left. If it goes too far you can use quick taps to the l key to inch it back to about 90.

  • Press the l letter key at a quick rate for 5 seconds and the Magni will rotate clockwise back to the starting point and will have the 3rd line that says ‘degrees’ now show the 3rd number to be near 0.

Another mode you may want to try is while the robot is up on blocks so drive wheels don’t touch the ground you can get wheels to run a fixed speed as follows:

rostopic pub -r 10 /cmd_vel geometry_msgs/Twist '{ linear: {x: 0.3} }'  

If you want the robot to continuously rotate this can be done directly on the ground or on blocks as follows:

rostopic pub -r 10 /cmd_vel geometry_msgs/Twist '{ angular: {z: 0.5} }'

3.3 ESTOP Testing In A Running Full System

There have been other ESTOP tests that appear earlier in Part 1. The reason for these tests is to validate ESTOP operation when the host has been sending movement command to the MCB.

NOTE: These tests require a rev 5.0 or later MCB board. YOU MUST NOT DO THIS TEST ON REV 4.9 boards as it will be dangerous!

Be sure the motor node is running which can be easily seen with a rev 5.2 or later MCB by inspection that both the ‘SIN’ and ‘SOUT’ leds in top center of the MCB board are blinking quickly.

Place the robot on blocks so it does not ‘get away from you’ for these tests.

3.3.1 Entering The ESTOP state with Movement In Progress

Run the joystick or use ‘twist’ to make motors actively move. Press ESTOP to active state which will cause the ‘Motor Power’ led to turn off in the lower right of the MCB.

Verify the motors will no longer have power and will slow to a stop with mild ‘self braking’ resistance to movement.

3.3.2 Exiting The ESTOP state with Movement Commands

With the robot already in ESTOP state so there is no motor power, run the joystick or the twist program actively for a couple seconds and while doing so release the ESTOP while still issuing movement commands.

Verify that the robot will start moving at the speed it is being commanded in a controlled way and not at full speed or other speed.

No matter how many movement commands were issued when ESTOP is active, it is only on the release of ESTOP after a half second or so that that velocity will be re-enabled as the wheels nicely ramp to speed again.

3.4 Speed Tests:

The speed tests verify proper operation of speed regulation and limits. These tests are done from the command line without the teleop twist program so use Control-C if you have the teleop twist program running.

These tests should be done with the robot on ‘blocks’ for the big powered front wheels so the wheels do not touch the floor. Normally we put a block of wood or a small stack of books under the front of the robot and it raises it up so the wheels do not touch the floor.

Put a piece of tape on the outside of a wheel so while testing we can count revolutions to get the actual speed.

3.4.1 Medium Speed Test:

Here we look to verify a medium speed is correctly regulated for both forward and backward driving. This test is done from the command line without the teleop twist program so use Control-C if you have the teleop twist program running.


Type the following command and hit enter so the robot moves at 0.3 meter per seconds

  • Type this: rostopic pub -r 10 /cmd_vel geometry_msgs/Twist '{ linear: {x: 0.3} }'

  • Verify the speed is about 0.3 meter per second by watching that the wheels both turn one full revolution forward in about 2 seconds. Use Control-C to stop movement.

  • Type this: rostopic pub -r 10 /cmd_vel geometry_msgs/Twist '{ linear: {x: -0.3} }'

  • Verify the speed is about 0.3 meter per second reverse and that the wheels both turn one full revolution forward in about 2 seconds. Use Control-C to stop movement.

3.4.2 Maximum Speed Limit Test:

We will drive at the max speed limit value will cause the robot to not exceed the default 1 meter per second setting. This test is done from the command line without the teleop twist program so use Control-C if you have the teleop twist program running.

This test is best done using a stopwatch and timing how long 10 wheel revolutions takes.


Type the following command and hit enter so the wheels rotate at 1 meter per second

  • Type this: rostopic pub -r 10 /cmd_vel geometry_msgs/Twist '{ linear: {x: 1.0} }'

  • Verify the speed is about 1 meter per second by watching that 10 turns of the wheel take about 6 seconds. The circumference of the wheels is near 0.64 meters. Use Control-C to stop the movement.

  • Type this: rostopic pub -r 10 /cmd_vel geometry_msgs/Twist '{ linear: {x: -1.0} }'

  • Verify the speed is about 1 meter per second in reverse by watching that 10 turns of the wheel take about 6 seconds. The circumference of the wheels is near 0.64 meters. Use Control-C to stop the movement.

3.5 Deadman Timer Testing:

The robot is designed to return to zero speed if it loses touch with constant host velocity commands.

  • Startup and run the robot on blocks at a constant speed. Kill the motor node OR disconnect serial (if your system allows). The motor node can be stopped and starting using:

    sudo systemctl stop magni-base.service

RESULT: The robot will return to stopped state with wheels actively locked.

  • Start or re-connect serial to the motor node using

sudo systemctl start magni-base.service

RESULT: Robot should be operational after the motor node starts (takes 15 or more seconds to start).

For re-connect of serial it will start back up in a second or less.

Part 4: RaspiCam and Sonar Board tests

4.1 RaspiCam Camera Test:

There is a very simple way to test the RaspiCam camera on the robot. This test will generate a jpeg still picture in about 6 seconds just to check the camera functionality.

raspistill -o testpicture.jpg

To verify the camera is operating properly the testpicture.jpg file needs to be moved to your laptop or other computer that has a jpeg picture viewer. If it is too difficult to move the picture using ftp or some other linux operation, the next best thing is to look at the file size. This can be done in the line below and the reply shows the 1543213 as the size in bytes for the jpeg image file.

ls -l testpicture.jpg
-rw-rw-r-- 1 ubuntu ubuntu 1543213 Aug  4 08:18 testpicture.jpg

If you have previously setup a laptop to be running ROS and have your Magni setup to be the ROS_MASTER you can start the raspicam node on the magni

roslaunch raspicam_node camerav2_1280x960.launch

Then on the laptop which has graphics you can view live video like this:

rosrun image_view image_view image:=/raspicam_node/image _image_transport:=compressed  

4.2 Sonar Board Test:

If you have installed and enabled the sonar board using the install guide viewed HERE then you can verify sonar operation in realtime once the robot has been started.

An easy way to see all 5 sonar ranges if they are working is to use the following command which continuously shows all 5 ranges

rostopic echo /sonars | grep -e frame_id  -e ^range

The sonar node publishes a sensor_msgs/Range message for each sonar reading. Using rostopic echo /sonars you can view all the sensor readings in one topic where the frame_id of sonar_3 would be for the front facing sonar 3. Using the table that will follow you can place boxes in front of sensors to gain confidence that each sensor is showing the distance to that object. A thin bar may not be seen properly and you may get mixed messages for what is behind it or may see the bar so use large objects for this test.

There is one separate topic for each sensor as seen in the table that follows. This table also has the jack number and 50-pin connector pins for echo and trigger

Topic Direction Jack Trig Pin Echo Pin
/pi_sonar/sonar_0 Far right J5 38 40
/pi_sonar/sonar_1 45 degrees left J1 32 36
/pi_sonar/sonar_2 45 degrees right J6 16 18
/pi_sonar/sonar_3 Front J4 13 15
/pi_sonar/sonar_4 Far left J2 35 37

Rviz can visualize these messages as cones. There are launch files to do this in: (the source package, not the binary packages)

The move_basic node uses the messages published by the sonar node to determine proximity to obstacles.

4.3 Touchscreen Display

Some products using recent images for newer products support a 7 inch Raspberry Pi touchscreen display. If you have such a product with proper SD card image for the product the display would light up and respond to touch activations.

This section is for using command line tools to detect the presence and health of the display without having to see the display in person.

Detection using command line is done by looking to see if the kernel log found the display. If the line below returns it was found then it is online.

dmesg | grep -i _fb | grep found

4.4 IMU Expander Board With IO port

A small board that fits under the OLED display has been developed so we can use an IMU in the product as well as have some extra leds and a small amount of user supplied simple slow speed IO.

If you have obtained this board then the I2C bus scan shown earlier in this page would show I2C addresses of 21 and 28. See table in the section above called I2C Bus Devices.

You can send a byte to the 8-bit IO port with the command below where the 3 leds are the upper bits and low=on. A value of 0xdf lights left led0xbf lights middle one and 0x7f lights right hand led. The 0x21 is the I2C address of this port. Set bits to 1 so they act as inputs from the jack when read using the i2cget command below

i2cset -y 1 0x21 0xdf       Turns on just the left leds
i2cget -y 1 0x21            Reads all 8 bits. A switch to ground gives 0

Detection of the BNO055 on the I2C bus can be seen using the I2C bus scan. We can also readback the chip ID register if we first ensure the BNO055 is not being reset because we have one line of the port that if low keeps the BNO055 in reset. So use these two command to release reset then read chip ID register that is always 0xa0

i2cset -y 1 0x21 0xff       Assures the BNO055 out of reset mode
i2cget -y 1 0x28            Reads back chip ID regsiter, always 0xa0

Part 5: Built In MCB Selftest

The robot is able to test some of it’s own subsystems. This ability is most capable starting with MCB 5.2 and will be first introduced in firmware version v36.

This section has been broken out from basic MCB tests due to it’s complexity merits it’s own section.

The results of the selftest will be available as status bits in a register of the MCB board and many of the tests have the ability to show up as blink codes on the status led should the error be detected.

The blink codes will be shown by the status led goes dark for a half second then a series of 2 to 4 long and short blinks occur followed by another half second of darkness before normal blinking returns. If a selftest fails with more than one error only the one considered the most important is visually seen on the LED.

Here is the table of blink codes

Blink Code Error Description
Long Short Short Short Low Battery voltage
Short Long Long Short 5V main or 12V main power error
Long Short Short Long 5V Aux or 12V Aux power error
Long Long Motor Test Failed

Default Power on Selftest

There will be a simple set of checks to look at the power supply levels every time the robot is started for any MCB of version 5.2 or later. If any of the 5V or 12V power supplies are not functional an error will result as a one of the voltage blink codes seen in the table above.

If the main battery is getting low an error will result but the robot will be allowed to start. The main battery test will work on all version of the MCB. The battery low condition shows up as a long blink followed by 3 shorter blinks. This blink code also will happen every 45 seconds so watch for this to remind you battery is very low which leads to erratic operation.

The Motor And Wheel Encoder Test

A test of the two drive wheels can be enabled by connecting TP4 to ground as the MCB is powered on. On MCB rev 5.3 and beyond this is easily done by using a standard 0.1” spacing jumper placed on the back of the board seen from battery compartment. Place the jumper between the bottom 2 pins on the TP4 side on the 3-pin P706 header located near the center on the back of board then power up the robot.

The drive test is testing wheel sensitivity as well and to run properly the robot front wheels should not be on the ground so we suggest a block of wood or other object be placed under the front of the robot so the wheels do not touch the ground when this test is run. Both wheels will turn a small amount one way and then another way in this short 8 second test.

Normally when this works the status led will simply drop into it’s normal single dropout blink every 5 seconds or so. If you see a series of two long blinks that indicates the motor test failed.

You can force this test to fail by holding back the wheels with reasonable force as this test runs which will force the blink code of Long Long

The Runtime Battery Low TEST

Every 45 seconds as the robot runs the main battery will be checked and if the battery supply drops to 22.2 volts a low battery condition will be detected and show up as an LED blink code of Long Short Short Short The threshold for this test is settable in firmware but the feature to set it using the host has not been implemented as of April 2020.

Simulate Failure On Power Supply Tests

You can force the main power test fail code by connecting the TP4 testpoint to ground through a 2.2k or 4.7k ohm resistor as the test runs on power up.

You can force the aux power test to fail by connecting the TP3 testpoint to ground through a 2.2k or 4.7k ohm resistor.

Programatically Running Selected Parts Of the selftest

Support for selection of one or more of the selftests to be run is done through some new registers in the firmware. Register with hex address 0x3b can request tests and register with hex address 0x3c will report results.

In order to run these tests the main host code must be stopped first using sudo systemctl stop magni-base and then a new version of a python test tool in the ubiquity_motor repository in the scripts folder which is called This script is not distributed yet but once available can be used to run 1 or more tests and report the results. More will appear here once it is supported.

We hope to support tests in the future through more standard ROS mechanisms.