Out with the old:	In with the new:
The orginal RAMB (Click to enlarge)	The new RAMB II (Click to enlarge)

In January 2006, Robodyssey Systems released the RAMB II, their new and improved motherboard for the BX-24 and BasicStamp families of microcontrollers. Starting in 2006, Robodyssey will ship this new motherboard with all of their robot systems, including the Mouse robot, which was prominently featured in my book. While the new motherboard represents significant technological improvements, the effect on my book is insignificant. Also, the RAMB II has the same small, footprint as the original, making integration of this new board into old projects a non-issue. In addition, with new low-profile capacitors and a voltage regulator that lies flat, the height of the RAMB II is even lower than the original and its components are less likely to be bent or damaged to rough handling.

• See the Robodyssey website for more information on the RAMB II kit. (Soldering required.)
• See the Robodyssey website for more information on the RAMB II. (Assembled -- no soldering required.)

In this document, I'll point out other reasons why the new board is such an improvement and show you how to use the new RAMB II in conjunction with my book, which was written for the original RAMB. If you have my book and are using the RAMB II, disregard the first four paragraphs of Section 5, Chapter 1 on pages 8 and 9. Follow the steps outlined here instead.

Table of Contents for this Page

1. RAMB II Versus the RAMB
2. Inserting the BX-24 into the RAMB II
3. Emulating the Original RAMB (The single power supply option)
4. Using the RAMB II's Dual Power Supply Option
5. Other Features Unique to the RAMB II

RAMB II Versus the RAMB

Here's a quick look at the differences between the RAMB II and the original RAMB microcontroller motherboards.

RAMB II RAMB Assembled Dimensions (L x W x H) 7.06cm x 4.85cm x 1.61cm 2.78" x 1.91" x 0.63" 6.93cm x 4.97cm x 2.27cm 2.73 x 1.96" x 0.89" Mass (includes BX-24) 31.80g 1.12oz 33.30g 1.17oz Low-profile components Yes No Circuit board trace widths 1.52mm 0.060" 1.07mm 0.042" Maximum rated current 3A 3A Regulated power on/off switch Yes No Zero-Force Insertion (ZIF) microcontroller socket Optional Standard Protection from reverse microcontroller insertion Yes Yes Protection from reverse sensor/motor hookup Yes, with Futaba-type end connectors. No Protoboard/Breadboard connectivity Female sockets on every I/O pin plus power and ground. Yes, with female-to-male jumper wires. Dedicated LCD control pins Yes No Number of power supplies allowed 1 or 2 (Jumper selectable) 1 Power supply function One supply can power the entire board (like the RAMB) or two supplies can be used: one to power the 5V regulated logic side (i.e., the right-hand-side of the board) and another supply can power the unregulated side (i.e. the left-hand-side of the board). One supply powers both the logic (i.e., right) and unregulated (i.e., left) sides of the board. [Return to the top.]

Inserting the BX-24 into the RAMB II

Carefully insert the BX-24 into the 24-pin chip socket on the RAMB II as shown in Figure 2. Unlike the original RAMB, it is possible to plug the chip in backwards -- see Figure 1 below for the correct orientation of the BX-24: Click on the image below to enlarge it. Figure 1. The correct layout of the RAMB II with BX-24. Be careful that all of the BX-24 pins are properly seated and that you apply an even amount of pressure when inserting the microcontroller. Applying too much force at an angle will bend the pins of the BX-24. Note that the microcontroller's pins are longer than the depth of the socket. The BX-24 will sit slightly above the top of the socket when fully inserted as shown in Figure 3. The new motherboard is not shipped with a zero insertion force, or ZIF, socket like the original board did. (See Figure 4.) However, you can contact Robodyssey if you would like your RAMB II shipped with a ZIF socket. (This will add a few dollars to the motherboard's cost.)

Click on the images below to enlarge them. Figure 2. Apply even, downward pressure to insert the BX-24 into the RAMB II. Figure 3. The pins of the BX-24 will be visible after insertion into the RAMB II. Figure 4. The original RAMB with a zero insertion force (ZIF) socket. The ZIF socket is blue.

[Return to the top.]

Emulating the Original RAMB (The single power supply option)

While the new RAMB II motherboard has many new and useful features, some users and readers of my book may wish to emulate the original RAMB. Unlike the RAMB II, the original RAMB had only one power receptacle and one power switch. One battery pack was therefore used to power the microcontroller as well all the peripheral devices such as servos, IR sensors, and voltage divider boards. Emulating the original RAMB with the new RAMB II is easy to do. Just follow these steps:

When you use only one power supply, connect the power jumper, as indicated by the arrow in Figure 5. (This is the jumper's default setting.) This jumper electrically connects the power pins on the left-hand-side of the RAMB II to the right ("Main") power receptacle, which is highlighted with the yellow circle in Figure 5. This jumper will force you to use only one power supply just like the original RAMB did. Now, plug your battery pack into the RAMB II's right power receptacle, as shown in Figure 6. Like its predecessor, the RAMB II is equipped with safety power receptacles. If your battery pack is not equipped with a notched safety connector, be sure that the red wire from the battery pack is connected to the positive (+) pin of the motherboard's power receptacle. Notice that the new motherboard does not have a green LED to serve as a polarity indicator. (The safety power receptacles prevent plugging the battery cable in backwards.) Warning: With the power jumper in place, do not connect another power supply to the left power receptacle. Power-up the BX-24 and the regulated power pins on the right-hand-side of the RAMB II by simply turning on the Main power switch. This switch is labeled "Main" on the circuit board and is highlighted with the red circle in Figure 7. When the Main switch is closed (that is, turned on), the red LED will illuminate (see Figure 7), indicating that the microcontroller and the 5V regulator is being supplied with electricity. That is, when the Main switch is closed, the BX-24 is powered up and a regulated (constant) 5 volts is sent to power pins 8-15 on the right-hand-side of the board. Next, turn on Secondary power switch located on the left-hand-side of the RAMB II. This newly added switch is labeled "Sub" on the circuit board and is highlighted with the red square in Figure 8. Turning this switch to the on position will energize the power pins 0-7 with unregulated power directly from your battery. That is, when the Secondary switch is closed the green LED will illuminate (see Figure 8) and the supply battery voltage, Vin, will be sent to power pins 0-7 on the left-hand-side of the board. Even with the jumper in place, the Secondary power switch must be used to switch on and off unregulated (Vin) power to the center pins of busses 0-7. The Secondary switch is a nice addition because it allows us to shut off the power to pins 0-7 without having to turn off the power to the BX-24. For instance, we are now able to turn off our servos or buzzers while our program is running. This feature makes it super easy to test robotic applications. The RAMB II is now configured just like the original RAMB. You can now follow along in my book without any confusion or conflicts. [Return to the top.]

Click on the images below to enlarge them. Figure 5. The power jumper is in place. Figure 6. With the jumper in place, only one battery pack is used to power the RAMB II. Figure 7. When the Main switch is thrown, the right side of the RAMB II (including the BX-24) receives regulated power. Note that the red power LED is illuminated. Figure 8. When the Secondary ("Sub") switch is thrown, the left side of the RAMB II receives unregulated power from the battery. Note that the green power LED is illuminated.

Using the RAMB II's Dual Power Supply Option

One advantage of using the new RAMB II is its dual power supply option. Say that you need to power the BX-24 with one voltage source and your servos with another. The RAMB II now makes it possible. Here's how:

When using two power supplies, you must remove the power jumper, as shown with the yellow circle in Figure 9. This step is a critical one! Failing to remove the jumper will directly connect the positive terminals of two supplies! Almost certainly, this will cause the batteries to overheat and rapidly drain. By removing this jumper, we can use two power supplies -- an option not available to the original RAMB. (If you wish, you may store the jumper by connecting it to one of the power jumper pins as shown in Figure 10. When using two power supplies, be certain that you do not connect the jumper across both pins!) With the power jumper removed, plug your primary battery pack into the RAMB II's right power receptacle, as shown in Figure 11. Like its predecessor, the RAMB II is equipped with safety power receptacles. If your battery pack is not equipped with a notched safety connector, be sure that the red wire from the battery pack is connected to the positive (+) pin of the motherboard's power receptacle. Notice that the new motherboard does not have a green LED to serve as a polarity indicator. (The notched safety power receptacles prevent plugging the battery cable in backwards.) Next, plug your secondary battery pack into the RAMB II's left power receptacle, as shown in Figure 12. If your battery pack is not equipped with a notched safety connector, be sure that the red wire from the battery pack is connected to the positive (+) pin of the motherboard's power receptacle. Power-up the BX-24 and the regulated power pins on the right-hand-side of the RAMB II by simply turning on the Main power switch. This switch is labeled "Main" on the circuit board and is highlighted with the red circle in Figure 13. When the Main switch is closed (that is, turned on), the red LED will illuminate, indicating that the microcontroller and the 5V regulator is being supplied with electricity. That is, when the Main switch is closed, the BX-24 is powered up and a regulated (constant) 5 volts is sent to power pins 8-15 on the right-hand-side of the board. Next, turn on Secondary power switch, which is located on the left-hand-side of the RAMB II. This newly added switch is labeled "Sub" on the circuit board and is highlighted with the red square in Figure 13. Turning this switch to the on position will energize the power pins 0-7 with unregulated power directly from your secondary battery source. That is, when the Secondary switch is closed the green LED will illuminate and the secondary battery voltage, will be sent to power pins 0-7 on the left-hand-side of the board. The Secondary switch is a nice addition because it allows us to shut off the power to pins 0-7 without having to turn off the power to the BX-24. For instance, we can now turn off our servos or buzzers while our program is running. This feature makes it super easy to test robotic applications. The RAMB II is now configured to run off of two power supplies. [Return to the top.]

Click on the images below to enlarge them. Figure 9. The power jumper must be removed if two power supplies are going to be used! Figure 10. It may be convenient to store the jumper on ONE of the power jumper pins. Figure 11. With the jumper removed, connect the Main battery pack to the right power receptacle. Figure 12. With the jumper removed, connect the Secondary battery pack to the left power receptacle. Figure 13. When the Main switch is thrown, the red LED is illuminated and the right side of the RAMB II (including the BX-24) receives regulated power from the Main battery. When the Secondary ("Sub") switch is thrown, the green LED is illuminated and the left side of the RAMB II receives unregulated power from the second battery.

Some Benefits of Using Multiple Power Supplies

Having more than one battery pack power up your RAMB II motherboard has several advantages, including: Applications run longer because you have two sets of batteries to share the load. While the BX-24 runs fine off of a 9V source, many devices, such as servomotors, are not meant to run off of a 9V battery -- the voltage is too high. Operating the RAMB II in dual-power mode, you can run the BX-24 and the regulated-side of the RAMB II with an alkaline 9V battery and run the servomotors on the right-side of the board with a smaller supply, such as 4 AA alkalines or 6 AA NiMH rechargeables, as shown in Figure 14. Isn't life great?! Servomotors and other current-hogging devices consume a lot of power. But even if the Secondary battery pack feeding these devices runs down, your program will continue to execute until the Main battery pack dies. This feature really comes in handy if you use two solar cells to power the board. (Often, using one solar cell is problematic when servomotors are involved; the motors draw so much initial current that the power to the BX-24 drops out and the program resets itself.) [Return to the top.]

Click on the images below to enlarge them. Figure 14. In dual-power mode, you can use a 9V battery as your Main source and not worry about over-driving your servos.

Other Unique Features of the RAMB II

There is more to the RAMB II than just another power receptacle and an additional switch. Robodyssey engineers have added many thoughtful and handy cost-saving and safety-conscious features, such as:

Protoboard/Breadboard Connectivity Have you ever had the need to send data between the I/O pins of the BX-24 and a protoboard or some other external circuit? If so, wouldn't it be nice if this could be done easily, without having to make your own jumper wires? Now, with the RAMB II, connectivity is a breeze! Robodyssey has added female I/O sockets adjacent to each of the BX-24's 16 pin rows, making prototyping and breadboarding a snap. Now, I/O data can be transmitted or received via a single wire. Simply strip the end of a single-conductor wire (see Figure 15) and plug it into one of the female sockets, as shown in Figure 16. What could be easier? Along these same lines, Robodyssey has also added female sockets for easy connection to the RAMB II's ground, 5V regulated, and Vin unregulated voltage pins. Now there is no need for a separate power source for your breadboard circuits, nor do you need to solder your own jumper wires for this purpose -- wires with two stripped ends are all you need to do the trick. See Figure 17 for an illustration of how to connect the BX-24's regulated power and ground to a nearby breadboard. Teachers of electronics and tinkers in general are sure to appreciate this new feature! Positive Pin Orientation With the addition of the female I/O sockets mentioned above, it is now impossible to plug cables with Futaba end connectors in backwards. Futaba end connectors have a protrusion on the side (see Figure 18) that, when used with the RAMB II, prevents the careless reverse hook-up of your sensors and servomotors. This feature will save you a lot of money and heartache, especially if you teach a room full of inexperienced students, who aren't always as careful and they should be. Low-Profile Components When Robodyssey redesigned its motherboard, they made a few cosmetic changes, which have significantly increased the robustness of the RAMB II. The RAMB II is now assembled with low-profile capacitors and its voltage regulator lies flat (see Figure 19), which means that these components are less likely to be bent or damaged due to accidental drops or rough handling. Overall, the RAMB II is 6.7mm shorter than the original RAMB. Dual Power Indicators The new RAMB II motherboard features two power LEDs, shown in Figure 20. When the "Main" power switch is turned on, the red LED is illuminated, indicating that the BX-24 is powered up and and a regulated (constant) 5 volts is sent to power pins 8-15 on the right-hand-side of the board. When the "Secondary" power switch is turned on, the green LED is illuminated, indicating that power pins 0-7 on the left-hand-side of the board are receiving unregulated power directly from the battery. (If the motherboard is configured for dual power, the power delivered to these pins comes from the secondary battery.) Dedicated LCD Control Pins Robodyssey has added three easy access pins to connect signal, power, and ground to external serial devices such as LCD panels. These pins, which are circled in Figure 21, allow you to communicate with an LCD panel, for example, without using up one of the 16 I/O pins of the BX-24. Take a look at my LCD tutorial, to learn how to control an LCD panel with both the standard I/O pins of the BX-24 and with the dedicated serial pins unique to the RAMB II. What?! You don't have an LCD panel? Buy your own 2x16 LCD panel from NetMedia. They're way cool and so easy to use! (And cost less than $40!) Noise Reducing Capacitors Even though the RAMB II now incorporates low-profile capacitors (see above), they still offer the same superb signal filtering that we've come to expect from Robodyssey motherboards. The bottom line: signal noise is effectively eliminated, and a clean, pure signal is transmitted and received. As always. Higher Current Rating When Robodyssey redesigned their motherboard, they upgraded their components and increased their circuit trace widths (see Figure 22) by 43% so that it can now handle currents up to 3A. Of course, you must still operate within the current limits of your microcontroller. (For the BX-24, the current limit is 0.08A (80mA) for each I/O (signal) pin.) [Return to the top.]

Click on the images below to enlarge them. Figure 15. Simply strip a wire and you are ready to connect your BX-24 to a breadboard. Figure 16. Insert the stripped wire into one of the 16 female I/O sockets featured on the RAMB II, and you are able to transmit and receive data along that wire! Figure 17. This figure illustrates how easy it is to connect the BX-24's regulated power and ground to a breadboard. Figure 18. Use Futaba end connectors and you'll never have to worry about plugging a component in backwards again! Figure 19. The RAMB II is made with low- profile components and the voltage regulator now lies flat, reducing the risk of damaging components due to rough handling. Figure 20. The red LED indicates that the Main power is on. The green LED tells us that the Secondary ("Sub") switch has been closed. Figure 21. The RAMB II makes it easy to communicate with serial devices, such as LCD panels, with dedicated serial pins (circled above). Figure 22. With wider traces and updated components, the RAMB II can now handle electrical currents up to 3A.