1 ‐ Getting started with Tapster 2
Now that you've got your Tapster, all that's left is some quick setup and you'll be ready to tap away to your heart's content. This shouldn't take more than 15 minutes.
One pre-assembled Tapster
Six arms (ball bearings attached) and one end effector with stylus
One alligator clip
One USB cable
One power supply (9V - 1A -- design may vary)
Attaching the arms is simple. Connect the ball bearings on one end of the arm (it doesn't matter which end) to the arm holder mounted on top of the robot.
The next step is to attach the end effector to the arms. Make sure that the screw in the end effector is aligned with the Tapster logo, and connect the ball bearings on the other end of the arms to the magnets in the end effector. The stylus tip should be pointing down.
The third step is to attach the alligator clip. First, plug one end into the ground on the daughter board.
Then clip the other end to the top of the stylus.
This allows the stylus to function properly -- without it, most screens would not recognize Tapster's tapping.
Plug the Type B USB connector (the squarer one) into the back of the Arduino motherboard. Plug the Type A connector (the rectangular one) into your computer.
Then, plug the power supply's barrel plug into the back of the motherboard, and plug the other end into an outlet.
If everything is working properly, you should see some lights come on.
The standard Tapster currently uses 3 servos. These servos are connected to pins 9, 10, and 11 on the daughterboard. If, for some reason, these come unplugged, or are plugged in incorrectly, Tapster will not work right.
Here is an image showing which servo corresponds to which pin.
It may be worth double checking that they are wired to the correct pins, and the wires are in the right orientation. The black wire, which is the ground wire, should line up with the "G" and the yellow wire, which is the signal wire, should line up with the "S".
Each bot should come with Firmata already loaded on the motherboard; however, it's good to double check that this is the case and hopefully avoid some nasty errors.
Set-up is straightforward. The IDE is found here.
Go to Tools > Port and select the port that the board is connected to. If no port appears, the device drivers may still be installing, and you'll have to wait for them to finish.
To ensure that the board is working, run a simple Blink sketch. This is found in File > Examples > 01. Basics. Load the sketch and upload it to the board (File > Upload).
You should be able to see the yellow LED on the motherboard blinking on and off every second.
Optional step: Modify the time interval, re-upload the sketch, and check to see that the board is now blinking at a different rate.
Open up the StandardFirmata sketch (File > Examples > Firmata) and upload it to the board.
Firmata allows us to more easily communicate with the motherboard, greatly simplifying things.
I would recommend using one of the installers found here (this also installs npm). If you would prefer to use another method of installation, look up a tutorial on Google.
Open up the command line interface of your choosing and type npm -v. If npm was installed properly the version number should be spit out.
Using the command line, navigate to the Tapsterbot software folder. Then, type npm install to install the modules that Tapster requires to run.
Tapster's configuration file is config.js, located in the software folder, which you are free to edit. Many of the values should be left alone -- these are marked as such. The rest you can modify to change the speed, accuracy, and smoothness of the Tapster's functions.
- e, f, re, and rf are the lengths of components of Tapster. Tapster is a delta robot, which uses inverse kinematics to calculate the angles to move to. e, f, re, and rf are values that are necessary for calculating these angles -- for more information on inverse kinematics and the way delta robots work, see this post on TrossenRobotics.
- The in_min and in_max values for all three servos are used for mapping points.
- The baseWidth and baseHeight are the dimensions of drawing area of the baseplate. Although the full baseplate is larger than these values would lead you to believe, Tapster can only reliably reach part of the baseplate because of the way it is designed. These values are used for mapping points, and should not be changed.
- The out_min and out_max values for all three servos are also used for mapping points; however, they change from servo to servo and so should be changed after calibrating each servo (see below). Default: 0, 90
- penHeight is the default z-level that the robot should move to. A higher value raises the pen, and a lower value lowers it. Default: -140
- drawHeight is the z-level that the robot should draw at. It is used when using the whiteboard insert and dry erase markers. Because dry erase markers lose their tip after being used frequently, this value might need to be changed over time. A higher value raises the marker and a lower value lowers it. Default: -152.5
- delay is the amount of delay to be used in SVGReader commands. Each command will take delay milliseconds or more to complete. A higher value of delay will result in more accurate and smoother drawings, at the expense of making it slower; a lower value will result in a less accurate and less smooth drawing, but will be much faster. Default: 150
- defaultEaseType is the default easing algorithm to be used when none is specified. For the list of easing algorithms, look at motion.js. A value of "none" means that unless specified, no easing algorithm should be used. Default: "linear"
It is possible to specify a configuration file other than the default config.js. When launching bot.js, input the path to the config file as a string parameter.
Navigate to the src folder and type node bot.js. This will power the robot and make it listen to any commands that you give it.
To specify a configuration file other than the default one, put the path to the file as a string parameter.
The Hi-Tec 311 servos, which are used in the current design of Tapster, require some calibration to be done to ensure the highest level of precision possible. To do this, first remove the arms.
Once that is done, you can begin to calibrate the servos. The goal is to figure out at what values the servo mounts are completely horizontal and completely vertical, and then input those values into the config file to be used in a mapping function.
Use the to command to move the servos.
This is what the the mount should look like at its out_min value
This is what the mount should look like at its out_max value
The values should be put in config.js in the out_min and out_max variables for each servo.
Tapster comes with a wide array of functions that can be used to test itself. You can tell it to move to specific points using the go command (ex: go([0, 0, -140])); you can tell it to draw a square with any sidelength (ex: draw.drawSquare(40)); you can tell it to draw an image from an .svg file (ex: svg.drawSVG("C:/Projects/Tapsterbot/software/src/example/tutorial.svg"); or you can try some of the other methods found in bot.js, draw.js, and SVGReader.js.
Keep in mind that if you call any functions from the latter two files you have to call them using an instantiated object of that file (ex: draw.drawCircle for draw.js and svg.hello for SVGReader.js).
For more information about using Tapster's functions, check out the other pages of this wiki.
The Tapster board's center corresponds to (0, 0), and the rest of the board is arranged like a standard graph. The upper right hand corner is the first quadrant and is +,+; the upper left hand corner is the second quadrant and is -,+; and so on. If the movement of the bot does not match up to this graph, something is probably wrong. Look at the troubleshooting section for more detail.
At this point, everything should be working properly and you're ready to use Tapster!
Double check that the port you selected is the correct one. You can try unplugging the cable and plugging it into a different one as well. If no port shows up, the device drivers are probably still being installed, and you will have to wait.
If nothing else fixes it, restarting your computer usually helps.
Plug the USB cable into a different port and re-launch.
The servo to pin wiring is probably messed up. Double check that the servos are connected to the correct pins, and that the wires are oriented properly (black to ground, yellow to signal).
If those are correct and the bot is still messed up, check the calibration values in the config.js file. If they are wrong they will mess up the mapping function and inaccurate values will be returned.
This can happen when the servos exert too much force. Easing algorithms are used to avoid this. Try specifying a different easing algorithm to use, or change the default easing algorithm. This will change the way the bot moves from one point to another, and should prevent the servos from tearing the arms off.
Side note: No lasting damage is done when the arms pop off. Magnets are used so that the arms will fall off rather than break in two when put under too much pressure.