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Handy Cricket FAQ

General Q&A




How do you hook up an LCD to your Handy Cricket?

At present, there is no LCD display device available for the Handy Cricket. However, there is a 4-Digit LED Number Display, ideal for displaying sensor readings.

(Last updated 2002-07-02)


What is the difference between the Handy Board and Handy Cricket?

The Handy Board is based on the Motorola 68HC11 processor and includes 32K of battery-backed static RAM, a 16x2 LCD display, four DC motor outputs, 7 analog inputs, 9 digital inputs, and a built-in rechargable nicad battery. The Handy Board is programmable in the custom Interactive C language, assembly language, or any general-purpose programming tool for the HC11 processor.

The Handy Cricket is based on the Microchip PIC16C715 processor and includes 4096 bytes of user program/data memory, two DC motor outputs, two analog inputs, bidirectional infrared communications, a custom Cricket Bus expansion jack, and a 4-AA cell battery holder. The Handy Cricket is programmed with the custom Cricket Logo language, available both in text and iconic versions.

To compare them briefly, the Handy Board is substantially more powerful, but the Handy Cricket is much smaller, lighter, and less expensive. Also, the Handy Cricket's Expansion Bus gives it more capability than the 2-motor/2-sensor basic functionality.

(Last updated 2002-06-21)


What is the relationship between the Handy Cricket and the other Cricket projects I have heard about?

Fred Martin did a series of projects around the idea of “programmable bricks” when he was a student (and later, a member of the research staff) at MIT. He worked on a project by the name of Crickets there.

When Fred left that university, he licensed the work that went by the name of “Cricket” and is launching products here by the name of “Handy Cricket.”

(Last updated 2002-06-21)


Why are they called Crickets?

We wanted to emphasize our Crickets' ability to communicate with one another, and we were inspired by the image of a field of crickets chirping with one another.

(Last updated 2002-06-21)


Where did the Handy Cricket come from?

The Handy Cricket is based on ideas and technology developed in the Cricket project of the Lifelong Kindergarten group, headed by Mitchel Resnick, at the Media Laboratory at Massachusetts Institute of Technology (MIT). The core Cricket design was begun by Brian Silverman with Fred Martin in 1995. Since that time, Bakhtiar Mikhak and Robbie Berg have made significant contributions to the Cricket design. Rick Borovoy suggested the name “Cricket” and contributed to early conceptual work. The Cricket team has also benefited from the work of more than a dozen MIT undergraduate students.

(Last updated 2002-06-21)


Is the Handy Cricket system open-source like the Handy Board?

No, the Handy Cricket system is not open-source. The university at which the Cricket was developed has retained rights to the design.

There are technical papers published that explain the architecture of the Cricket in fair detail (for example, an article in the IBM Systems Journal), so much of the Cricket design is public.

Fred is publishing additional articles that document the hardware design, software APIs, and interfacing methods. See the Cricket Tech section of the Handy Cricket web site.

(Last updated 2002-06-21)


The Handy Cricket seems bigger than the MIT Cricket.

It's true—the Handy Cricket is bigger than the research Cricket. The reason is that the Handy Cricket runs off of four AA batteries, while the research Cricket used a 9v battery.

The 9v battery is a cool form factor, but in real-world use, the research Cricket burns through them pretty quickly. We're talking a battery life of under an hour in some applications. At $2 a pop for a 9v alkaline, that gets expensive fast.

So the Handy Cricket is built somewhat bigger, but with a battery system that can last ten times as long as the research version of the Cricket.

(Last updated 2002-06-21)


What are the dimensions of the Handy Cricket?

The board of the Handy Cricket measures 2-1/4” by 1-7/8” (5.7 by 4.8 cm). With the battery pack, the full dimensions are 2-1/2” by 2-1/4” (6.4 by 5.7 cm).

(Last updated 2002-06-21)


When will you be releasing a USB Interface Cricket?

We have released the Cricket USB IR Beamer! It’s part number CXIR-USB from Gleason Research.

(Last updated 2009-06-10)


Can you view your sensor readings on your Cricket?

Yes. You can run a short Logo statement that tells the Cricket to continuously transmit a sensor reading as a series of IR bytes. These bytes automatically show up in the Cricket Logo software's Cricket Monitor display.

For example, to see the readings on sensor A, type the following statement into the Cricket Logo Command Center:

loop [send sensora]

The values will then show up in the Cricket Monitor display (above the Download button).

The Cricket will transmit the sensor A values until you press its Run/Stop button or turn it off.

(Last updated 2002-06-21)


Can you program the Handy Cricket with NQC?

No, you can not use NQC for programming your Handy Cricket. The only programming environments presently available for the Handy Cricket are Cricket Logo, a text-based IDE, and Logo Blocks, an iconic version of the Cricket Logo language. See the Cricket Software pages for more information.

(Last updated 2002-06-21)


Can the Handy Cricket and the RCX communicate with each other?

No, the Handy Cricket and the RCX use fundamentally different IR technologies and can not communicate with one another. The Handy Cricket comes with its own Serial-IR interface, which is not compatible with the LEGO RCX IR Tower.

(Last updated 2002-06-21)


The Cricket won't beep when I type "beep" in the Command Center.

If you are unable to communicate with the Cricket, try these things.
  1. Make sure the USB-serial driver is installed properly. You can get the driver from http://ftdichip.com/Drivers/VCP.htm.

    On a Windows system, you should have a new COM port when the Cricket Beamer is plugged in. Make sure to select that port in the Cricket software.

    Sometimes the driver install can get corrupted. You can remove it before trying again with this utility: FTCLEAN.

  2. Does the yellow LED on the Beamer blink when you try to communicate with the Cricket (e.g., when you type "beep <return>" in the command center)? It should. If it does, that means that the USB-serial port stuff should be working.

  3. Does the Cricket beep when you turn it on? It should. If it doesn't, you have low or dead batteries, or something's wrong with the Cricket.

  4. Before you try the beep command, is the Cricket's red "running" LED off? It must be off, or the Cricket will ignore communications from the computer. If the Cricket starts running its program immediately at power-on, hold down the Run/Stop button while powering on the Cricket. This will make the Cricket not run its program, and then it should boot up in the idle state (beeping once and then the red LED is off).

  5. Are the IR comms devices on the Cricket and Beamer aimed toward each other? Distance is not critical -- anywhere from a couple inches to a couple of feet will work -- but they do need to be aimed toward each other. (The further away they are, the more sensitive they are to the exact angular positioning.)

(Last updated 2010-05-05)


I want to read the Cricket's sensors from the serial port of my computer.

Here is one way to do it.

Using the Cricket Logo software, put the following program on the Cricket:

to reply
loop [
  waituntil [newir?]
  if ir = 1 [send sensora]
  if ir = 2 [send sensorb]

Put reply in the Run This line, download, and run the program.

Now, whenever the Cricket sees the value 1, it will reply with the value of sensora; if it sees 2, it will reply with sensorb.

From your program, set the serial line for 9600-N-8-1. Transmit a 1 (binary, NOT the ascii value) and read the reply. You'll first get the hardware echo from the serial interface (a 1, or whatever character you just sent) and then the answer from the Cricket.

(Last updated 2002-07-28)


Can I get the Cricket to automatically run its program when it is turned on?

Yes, you can do this. Firstly, load your program so that it will run when you press the Start button. (i.e., put the program you want to run in the "Run This" line.)

Then, when the Cricket is idle, type the following at the Command Center:

db $fff 0

Now power-cycle the Cricket. It will autostart your program.

(Last updated 2007-05-08)


Why are there two jacks per motor port?

There are two jacks per motor port so that you can easily reverse the direction that a motor is turning.

If you want a motor to turn in the opposite direction, you can unplug it, rotate the plug 180 degrees, and then re-plug it in the other jack.

You can also change the motor direction with the software commands thisway, thatway, and rd.

(Last updated 2002-12-01)


Can I power the Cricket with more than 6 volts?

Yes, it is possible to run the Cricket with a power supply larger than the stock 6v.

First, please refer to the image of the Cricket printed circuit board.

Remove the rectangular black component labeled D1. Then install a 78L05 or LM2931Z-5.0v voltage regulator in the 3 holes immediately underneath and to the right of the D1 position.

The upper hole is the regulated +5v output, the lower hole is the unregulated input, and the middle right-hand hole is ground.

Finally, replace the power supply of the Cricket with something in the 9 to 12 volt range, and you are all set.

(Last updated 2003-02-12)


What are the differences between the Handy Cricket and the MIT Crickets?

The Handy Cricket is most closely related to the MIT “Blue Dot” Cricket. Before explaining the differences, here's how they are the same. Both can run two motors and use two sensors. Their infrared communications are compatible. They have the same memory for user programs. Both have a pushbutton and a beeper.

Now, here are the differences:

  • MIT Cricket uses a 9v battery. Handy Cricket uses four AA cells.

  • Motor and sensor connectors are different.

  • Bus device connector and voltage levels are different.

(Last updated 2003-02-18)


How can I make the Cricket stop automatically running its program?

To make the Cricket stop running its program automatically, first hold down the Run/Stop program when turning on the Cricket. This will prevent it from running your program, and it will be idle, so you can talk to it.

Then, enter the following at the Command Center:

db $fff $ff

Power-cycle the Cricket, and it should no longer automatically run its program.

(Last updated 2007-05-08)


What are good DC motors to use with the Cricket?

Here are three motors that include geartrains so that you get good, usable output torque (rotational strength):

In terms of specifications, you should look for a motor that operates between 6v and 9v, and draws less than 500 mA of current.

(Last updated 2007-12-20)


Can I use a DC adapter with the Cricket?

Yes. There are a few possibilities depending on whether you have Handy Cricket or a Super Cricket.

For the Handy Cricket, you should remove the batteries and attach to the battery pack terminals that carry power into the circuit board. Look at the two wire prongs the connect the battery pack to the Cricket circuit board, and apply power to these battery contacts (make sure the batteries are removed!).

Note the + and - contacts as labeled on the circuit board or the battery pack.

Please be aware that the Handy Cricket does not have a built-in voltage regulator, so you need to use an adapter that provided regulated 5v or 6v output. Here is an example: Jameco regulated 6v, 500 mA adapter.

For the Super Cricket, you have two options.

  • Operating motors only from external power. The Super Cricket has a 2-terminal screw jack for applying the source of motor power. Normally there is a jumper wire that takes the power from the SC's own battery pack. But you can remove this wire (tape or cut off the exposed end) and then attach external power. Make sure to observe correct polarity (note the + and - terminals).

    If you use the Super Cricket in this mode, the electronics will still operate from the 4xAA pack. Only the motors will be powered from the external source. This is useful if you are doing a lot with the motors and need a separate power source.

  • Operating the whole Super Cricket from external power. With this approach, leave the screw terminal with its one wire intact, and remove the batteries. Then connect power to the battery pack terminals per the instructions for the Handy Cricket (above).

    Super Crickets ship with a built-in 5v regulator, so you can use (less expensive) unregulated power supplies. Here is an example: Jameco unregulated 6v, 800 mA adapter

    Note: This configuration can reduce the reliability of the Cricket, particularly when driving larger loads on its motor outputs. If you notice random crashes, go back to the first option (running the electronics from batteries).

(Last updated 2007-12-20)


What kind of servo motors work with the Super Cricket?

Most standard 5 and 6v hobby radio servo motors work with the Super Cricket. Look for the Futaba-style connector. This is a 3-wire standard with a female header on the servo motor cable. This plugs into the 3-pin header on the Super Cricket.

Tower Hobbies is a good supplier of servo motors. Here is a listing of standard sized servos.

Examples of standard servos that are compatible are the Futaba S3003, Hobbico CS-60, and Hitec HS-311.

You can also use mini- or micro-servos. The Futaba S3111 is an example.

(Last updated 2007-12-20)


What is a continuous rotation servo?

A continuous rotation servo is a servo motor that is not locked to travel only 180 degrees of back-and-forth motion. Instead, it can rotate freely like a regular gear motor. For example, it can act as the drive motor of a car or robot.

Continuous rotation servos are sometimes known as “sail winch” servos because they have been used by model boat builders to wind up the sheet rope on a model sailboat.

With the Super Cricket, continuous rotation servos perform the same function as a DC gear motor. They cost more than DC motors, so why would you use one instead of regular DC gear motor? The main reason is that you can get a bit more power out of a continuous rotation servo than you can from a DC motor on the Super Cricket.

Since the Super Cricket has 8 servo outputs and 4 DC motor outputs, you can mix and match as you like.

Here is a supplier for continuous rotation servos: Parallax/Futaba Continuous Rotation Servo.

(Last updated 2007-12-20)


How do I install the Super Cricket libraries?

To get the Cricket software installed, you perform the following:

1. Download and run the Cricket Logo Installer for PC (the 6.2 MB file).

2. Install the Software Update for 3.0 beamer. This is a file named CkLogo.jar and it goes in C:\Program Files\Cricket Logo\ .

3. Install the Super Cricket Libraries. These are a set of four files that go in C:\Program Files\Cricket Logo\lib\ .

(Last updated 2008-01-15)


Issue involving when and Super Cricket sensors C thru F

There is a known issue regarding the use of the “when” command and sensors C through F on the Super Cricket. The issue also exists in using sensors on the Motor/Sensor Expansion Board.

Specifically, if the "when" trigger includes reading any of the sensors C through F, things get flaky and don't work.

This is indeed a bug. It has to do with a threading issue. The "when" command evaluates its condition between the execution of the main user Logo code, and sensors C through F are implemented as a multi-byte series of communications between the main PIC and slave PIC.

In order to fix this, this communication would have to move into the Cricket virtual machine (presently, it's implemented in a user-level Logo library).

So for now, the best approach is to not use sensors C through F inside the condition of the when.

Alternately, one might strategically enable and disable the when, making sure it's disabled before any sensor C - F activity in the main user thread.

(Last updated 2008-01-08)


The Beamer's yellow LED is continuously on.

If the Cricket Beamer's yellow “transmit” LED is continuously on, something is indeed wrong.

If you have a serial Beamer (not the USB model):

First, unplug the Cricket Beamer from the serial cable. If the yellow LED turns off, then the Interface Cricket itself is OK.

Next check the serial cable. Make sure you have a straight-thru cable and not a “null” (inverting) cable. Pin 2 on one end should go to pin 2 on the other end, 3 to 3, etc.

Use a terminal emulator (like HyperTerminal on Windows) to test your COM port. Put the settings to 9600 baud, N (no parity), 8 (data bits), 1 (stop bit), no hand-shaking. When you're connected to the Interface Cricket, type on your computer's keyboard. You should see your keystrokes echoed on your screen, and the Cricket Beamer's yellow LED should blink once for each keystroke.

If you can get this working, then your hardware is ready for Cricket Logo.

(Last updated 2010-05-05)