With the myriad electronic devices available to the modeling community, I thought I could purchase anything I might need from one of the many companies that supplies these items. However, a requirement for a new device arose when I was completing installation of spoilers on an original-design glider. Each spoiler was controlled with its own servo, and both connected to a single channel with a Y connector. Mechanical adjustments, in addition to transmitter servo-travel programming.resulted in reasonable spoiler operation, but one would always close right before the other. Programming for more travel resulted in at least one servo chattering as it tried to go beyond the spoiler's mechanical limit. One would not want this condition to exist throughout an entire glider flight because of its continuous current drain on the radio battery. However. I noticed that if the receiver was turned off when the spoilers were fully closed, the chattering stopped (as would be expected) and the spoilers remained in their fully closed position. Necessity being the mother of invention, I conceived an electronic unit that would turn off the servo pulses after some short time period when the servo was near its end position corresponding to the fully closed spoiler condition. The servo would instantly come back to life when the servo channel signal changed. Such a device would only be useful if there was no holding force required (other than the servo's mechanical resistance) to maintain its end-of-travel position. Other applications would be where a mechanical stop could prevent full servo travel, as can occur with throttle operation, flaps in their retracted positions, and functional scale features such as movable canopies, hatches, and bomb bay doors. In these cases, if not precisely adjusted, the servo could be trying to move against a stop and drawing current from the flight pack during most of the flight. Description: The unit uses a small, programmed, eight-pin microcontroller (Digi-Key part number 12C508) made by Microchip. A connector from the unit plugs into the appropriate receiver channel, and the servo (or servos with a Y connector) connects to output pins mounted on the circuit board. The Chatter Buster will work with all systems using the conventional minus-plus signal orientation of the receiver-to-servo connections. It will not work with the older Airtronics systems unless von use an appropriate adapter. . .-.-.• , .. Servo A jumper—the same type used on computer boards—selects which end of the servo travel will have the chatter-elimination function. In one position the chatter-buster function will occur above all pulse widths greater than 1.8 milliseconds and will have normal operation for all pulse widths less than 1.8 milliseconds. In the other position, the function will occur at pulse widths less than 1.2 milliseconds and have normal operation at greater than 1.2 milliseconds. The normal servo-pulse width range is 1.0-2.0 milliseconds. There will be a delay of approximately a hall second after the pulse width enters the chatter-elimination range, to ensure that the servo reaches its required position before the servo pulse is interrupted. When in its no-chatter range described in the preceding, any slight change in the transmitted pulse width will immediately activate the servo pulse for another half second. The unit receives its power from the flight battery through the receiver and draws less than 1.5 milliamps; its weight is three grams. Construction: Refer to Figure 1 and its parts list for assembly details. The printed circuit (PC) shown is actual size and viewed from the copper foil side. I make my prototype boards using the following steps: 1) Cut the board to size. 2) Make a copy of the PC-board pattern for later reference. 3) Tape or use spray adhesive to attach the PC-board pattern to the copper side of the board. 4) Mark through the pattern at each hole locution using a small, sharp center punch. 5) Remove the pattern and clean the board with solvent and steel wool. 6) Using a permanent marker (black works best), draw the pattern between the appropriate marked hole locations to ensure good-size lands and solid coverage. 7) After drying, etch in a shallow cup or dish (plastic or glass) using ferric chloride (available from RadioShack®) until the etching is complete. This may take 15 minutes or more. Rinse in running water. 8) Clean off the permanent marker with acetone or a similar solvent. 1 9) Drill through the board at all the center-punch-marked locations using a #63 (0.036-inch-diameter) drill. If you do not want to make your own board, contact me for one that is commercially made. Solder a small, solid wire jumper and the two three-pin headers into position as shown in the component-layout drawing. Note the proper location of the straight and right-angle headers. The microcontroller integrated circuit (IC-1) is a programmed unit. If you have, or know someone who has, the capability to program these, contact me and I will E-mail the code file necessary to program the 1C. Contact me for programmed units if needed. Properly orient the 1C into the board with the small, half-round index mark as shown in the drawing. Solder all eight pins to the circuit-board lands. Solder the three servo-connector wires from the servo connector to the three positions shown in the drawing. Check to make sure that you have the proper polarity as indicated. Check the solder connections on the copper side of the board and make sure there are no solder bridges between traces. Place the jumper in one of the two positions on the straight header. Do not inadvertently place the jumper over the two +/-pins of the right-angle header: this would place a short on the battery when plugged in. Connect a servo with the proper orientation to the right-angle header. If connected with the orientation reversed, it will cause no problem but will not operate. Plug the Chatter Buster servo connector into the desired receiver channel. Apply transmitter and receiver power, and check operation. At one end of the travel, the servo should have no signal and the servo arm should be manually movable with no return holding power. Moving the control tor that channel should return the servo to normal operation. Move the jumper to the alternate position and check operation with this condition. A /4-inch length of '/2-inch-diameter heat-shrink tubing can be used to encase the unit and provide strain relief for the leads. Make sure the entire circuit board foil side is covered. After shrinking, trim the tubing to clear the jumper and servo header pins. Before installing in the model, place a short length of insulation over the exposed pin adjacent to the installed jumper. This pin will be at battery negative or positive, depending on which position is used. It is unlikely that this pin will contact any exposed conductor of opposite battery polarity, but placing the insulating sleeve over the pin will reduce any probability of shorts. I used a piece of preshrunk '/id-inch heat-shrink tubing. You could also use a piece of insulation stripped from an appropriate wire size. After installation, as with any change in a Radio Control setup, perform a radio range check to ensure reliable performance. This completes the Chatter Buster, and now it can be installed in the model.
Edition: Model Aviation - 2002/10
Page Numbers: 48, 49, 50
Edition: Model Aviation - 2002/10
Page Numbers: 48, 49, 50
With the myriad electronic devices available to the modeling community, I thought I could purchase anything I might need from one of the many companies that supplies these items. However, a requirement for a new device arose when I was completing installation of spoilers on an original-design glider. Each spoiler was controlled with its own servo, and both connected to a single channel with a Y connector. Mechanical adjustments, in addition to transmitter servo-travel programming.resulted in reasonable spoiler operation, but one would always close right before the other. Programming for more travel resulted in at least one servo chattering as it tried to go beyond the spoiler's mechanical limit. One would not want this condition to exist throughout an entire glider flight because of its continuous current drain on the radio battery. However. I noticed that if the receiver was turned off when the spoilers were fully closed, the chattering stopped (as would be expected) and the spoilers remained in their fully closed position. Necessity being the mother of invention, I conceived an electronic unit that would turn off the servo pulses after some short time period when the servo was near its end position corresponding to the fully closed spoiler condition. The servo would instantly come back to life when the servo channel signal changed. Such a device would only be useful if there was no holding force required (other than the servo's mechanical resistance) to maintain its end-of-travel position. Other applications would be where a mechanical stop could prevent full servo travel, as can occur with throttle operation, flaps in their retracted positions, and functional scale features such as movable canopies, hatches, and bomb bay doors. In these cases, if not precisely adjusted, the servo could be trying to move against a stop and drawing current from the flight pack during most of the flight. Description: The unit uses a small, programmed, eight-pin microcontroller (Digi-Key part number 12C508) made by Microchip. A connector from the unit plugs into the appropriate receiver channel, and the servo (or servos with a Y connector) connects to output pins mounted on the circuit board. The Chatter Buster will work with all systems using the conventional minus-plus signal orientation of the receiver-to-servo connections. It will not work with the older Airtronics systems unless von use an appropriate adapter. . .-.-.• , .. Servo A jumper—the same type used on computer boards—selects which end of the servo travel will have the chatter-elimination function. In one position the chatter-buster function will occur above all pulse widths greater than 1.8 milliseconds and will have normal operation for all pulse widths less than 1.8 milliseconds. In the other position, the function will occur at pulse widths less than 1.2 milliseconds and have normal operation at greater than 1.2 milliseconds. The normal servo-pulse width range is 1.0-2.0 milliseconds. There will be a delay of approximately a hall second after the pulse width enters the chatter-elimination range, to ensure that the servo reaches its required position before the servo pulse is interrupted. When in its no-chatter range described in the preceding, any slight change in the transmitted pulse width will immediately activate the servo pulse for another half second. The unit receives its power from the flight battery through the receiver and draws less than 1.5 milliamps; its weight is three grams. Construction: Refer to Figure 1 and its parts list for assembly details. The printed circuit (PC) shown is actual size and viewed from the copper foil side. I make my prototype boards using the following steps: 1) Cut the board to size. 2) Make a copy of the PC-board pattern for later reference. 3) Tape or use spray adhesive to attach the PC-board pattern to the copper side of the board. 4) Mark through the pattern at each hole locution using a small, sharp center punch. 5) Remove the pattern and clean the board with solvent and steel wool. 6) Using a permanent marker (black works best), draw the pattern between the appropriate marked hole locations to ensure good-size lands and solid coverage. 7) After drying, etch in a shallow cup or dish (plastic or glass) using ferric chloride (available from RadioShack®) until the etching is complete. This may take 15 minutes or more. Rinse in running water. 8) Clean off the permanent marker with acetone or a similar solvent. 1 9) Drill through the board at all the center-punch-marked locations using a #63 (0.036-inch-diameter) drill. If you do not want to make your own board, contact me for one that is commercially made. Solder a small, solid wire jumper and the two three-pin headers into position as shown in the component-layout drawing. Note the proper location of the straight and right-angle headers. The microcontroller integrated circuit (IC-1) is a programmed unit. If you have, or know someone who has, the capability to program these, contact me and I will E-mail the code file necessary to program the 1C. Contact me for programmed units if needed. Properly orient the 1C into the board with the small, half-round index mark as shown in the drawing. Solder all eight pins to the circuit-board lands. Solder the three servo-connector wires from the servo connector to the three positions shown in the drawing. Check to make sure that you have the proper polarity as indicated. Check the solder connections on the copper side of the board and make sure there are no solder bridges between traces. Place the jumper in one of the two positions on the straight header. Do not inadvertently place the jumper over the two +/-pins of the right-angle header: this would place a short on the battery when plugged in. Connect a servo with the proper orientation to the right-angle header. If connected with the orientation reversed, it will cause no problem but will not operate. Plug the Chatter Buster servo connector into the desired receiver channel. Apply transmitter and receiver power, and check operation. At one end of the travel, the servo should have no signal and the servo arm should be manually movable with no return holding power. Moving the control tor that channel should return the servo to normal operation. Move the jumper to the alternate position and check operation with this condition. A /4-inch length of '/2-inch-diameter heat-shrink tubing can be used to encase the unit and provide strain relief for the leads. Make sure the entire circuit board foil side is covered. After shrinking, trim the tubing to clear the jumper and servo header pins. Before installing in the model, place a short length of insulation over the exposed pin adjacent to the installed jumper. This pin will be at battery negative or positive, depending on which position is used. It is unlikely that this pin will contact any exposed conductor of opposite battery polarity, but placing the insulating sleeve over the pin will reduce any probability of shorts. I used a piece of preshrunk '/id-inch heat-shrink tubing. You could also use a piece of insulation stripped from an appropriate wire size. After installation, as with any change in a Radio Control setup, perform a radio range check to ensure reliable performance. This completes the Chatter Buster, and now it can be installed in the model.
Edition: Model Aviation - 2002/10
Page Numbers: 48, 49, 50
With the myriad electronic devices available to the modeling community, I thought I could purchase anything I might need from one of the many companies that supplies these items. However, a requirement for a new device arose when I was completing installation of spoilers on an original-design glider. Each spoiler was controlled with its own servo, and both connected to a single channel with a Y connector. Mechanical adjustments, in addition to transmitter servo-travel programming.resulted in reasonable spoiler operation, but one would always close right before the other. Programming for more travel resulted in at least one servo chattering as it tried to go beyond the spoiler's mechanical limit. One would not want this condition to exist throughout an entire glider flight because of its continuous current drain on the radio battery. However. I noticed that if the receiver was turned off when the spoilers were fully closed, the chattering stopped (as would be expected) and the spoilers remained in their fully closed position. Necessity being the mother of invention, I conceived an electronic unit that would turn off the servo pulses after some short time period when the servo was near its end position corresponding to the fully closed spoiler condition. The servo would instantly come back to life when the servo channel signal changed. Such a device would only be useful if there was no holding force required (other than the servo's mechanical resistance) to maintain its end-of-travel position. Other applications would be where a mechanical stop could prevent full servo travel, as can occur with throttle operation, flaps in their retracted positions, and functional scale features such as movable canopies, hatches, and bomb bay doors. In these cases, if not precisely adjusted, the servo could be trying to move against a stop and drawing current from the flight pack during most of the flight. Description: The unit uses a small, programmed, eight-pin microcontroller (Digi-Key part number 12C508) made by Microchip. A connector from the unit plugs into the appropriate receiver channel, and the servo (or servos with a Y connector) connects to output pins mounted on the circuit board. The Chatter Buster will work with all systems using the conventional minus-plus signal orientation of the receiver-to-servo connections. It will not work with the older Airtronics systems unless von use an appropriate adapter. . .-.-.• , .. Servo A jumper—the same type used on computer boards—selects which end of the servo travel will have the chatter-elimination function. In one position the chatter-buster function will occur above all pulse widths greater than 1.8 milliseconds and will have normal operation for all pulse widths less than 1.8 milliseconds. In the other position, the function will occur at pulse widths less than 1.2 milliseconds and have normal operation at greater than 1.2 milliseconds. The normal servo-pulse width range is 1.0-2.0 milliseconds. There will be a delay of approximately a hall second after the pulse width enters the chatter-elimination range, to ensure that the servo reaches its required position before the servo pulse is interrupted. When in its no-chatter range described in the preceding, any slight change in the transmitted pulse width will immediately activate the servo pulse for another half second. The unit receives its power from the flight battery through the receiver and draws less than 1.5 milliamps; its weight is three grams. Construction: Refer to Figure 1 and its parts list for assembly details. The printed circuit (PC) shown is actual size and viewed from the copper foil side. I make my prototype boards using the following steps: 1) Cut the board to size. 2) Make a copy of the PC-board pattern for later reference. 3) Tape or use spray adhesive to attach the PC-board pattern to the copper side of the board. 4) Mark through the pattern at each hole locution using a small, sharp center punch. 5) Remove the pattern and clean the board with solvent and steel wool. 6) Using a permanent marker (black works best), draw the pattern between the appropriate marked hole locations to ensure good-size lands and solid coverage. 7) After drying, etch in a shallow cup or dish (plastic or glass) using ferric chloride (available from RadioShack®) until the etching is complete. This may take 15 minutes or more. Rinse in running water. 8) Clean off the permanent marker with acetone or a similar solvent. 1 9) Drill through the board at all the center-punch-marked locations using a #63 (0.036-inch-diameter) drill. If you do not want to make your own board, contact me for one that is commercially made. Solder a small, solid wire jumper and the two three-pin headers into position as shown in the component-layout drawing. Note the proper location of the straight and right-angle headers. The microcontroller integrated circuit (IC-1) is a programmed unit. If you have, or know someone who has, the capability to program these, contact me and I will E-mail the code file necessary to program the 1C. Contact me for programmed units if needed. Properly orient the 1C into the board with the small, half-round index mark as shown in the drawing. Solder all eight pins to the circuit-board lands. Solder the three servo-connector wires from the servo connector to the three positions shown in the drawing. Check to make sure that you have the proper polarity as indicated. Check the solder connections on the copper side of the board and make sure there are no solder bridges between traces. Place the jumper in one of the two positions on the straight header. Do not inadvertently place the jumper over the two +/-pins of the right-angle header: this would place a short on the battery when plugged in. Connect a servo with the proper orientation to the right-angle header. If connected with the orientation reversed, it will cause no problem but will not operate. Plug the Chatter Buster servo connector into the desired receiver channel. Apply transmitter and receiver power, and check operation. At one end of the travel, the servo should have no signal and the servo arm should be manually movable with no return holding power. Moving the control tor that channel should return the servo to normal operation. Move the jumper to the alternate position and check operation with this condition. A /4-inch length of '/2-inch-diameter heat-shrink tubing can be used to encase the unit and provide strain relief for the leads. Make sure the entire circuit board foil side is covered. After shrinking, trim the tubing to clear the jumper and servo header pins. Before installing in the model, place a short length of insulation over the exposed pin adjacent to the installed jumper. This pin will be at battery negative or positive, depending on which position is used. It is unlikely that this pin will contact any exposed conductor of opposite battery polarity, but placing the insulating sleeve over the pin will reduce any probability of shorts. I used a piece of preshrunk '/id-inch heat-shrink tubing. You could also use a piece of insulation stripped from an appropriate wire size. After installation, as with any change in a Radio Control setup, perform a radio range check to ensure reliable performance. This completes the Chatter Buster, and now it can be installed in the model.
