Editing PIC based Stepper Motor Dancing Analog Clock
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*Name: PIC based Stepper Motor Analog Clock with Dancing Hands | *Name: PIC based Stepper Motor Analog Clock with Dancing Hands | ||
− | *Purpose: | + | *Purpose: A C library ( in source code form ) for serial communications ( RS232 ) together with a program demonstrating its use. |
− | *Status: This is a draft. Code works but still in refinement, code available, email russ_hensel | + | *Status: This is a very early draft. Code works but still in refinement, code available, email russ_hensel |
*Technology: Stepper Motors, PIC 16F877A and BoostC | *Technology: Stepper Motors, PIC 16F877A and BoostC | ||
*Author: [[russ_hensel]] ( where you can find an email address to reach me ) | *Author: [[russ_hensel]] ( where you can find an email address to reach me ) | ||
*License: Open source and object code. | *License: Open source and object code. | ||
− | This is an analog clock, with real hands driven by stepper motors. | + | This is an analog clock, with real hands driven by stepper motors. Because stepper motors are quite powerful the clock could be made quite large, 3 feet in diameter is probably within reach still using inexpensive ( salvage ) stepper motors. The project description includes eagle files for the circuits and a BoostC project with source code for the PIC. |
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=== Major Parts === | === Major Parts === | ||
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*2 Stepper Motors -- probably can be salvaged from printers or 5 1/4 disk drives ( where I got mine ) | *2 Stepper Motors -- probably can be salvaged from printers or 5 1/4 disk drives ( where I got mine ) | ||
*PIC16F877 processor -- Others can be used, but this guy has a lot of IO, quite a bit is used for the clock | *PIC16F877 processor -- Others can be used, but this guy has a lot of IO, quite a bit is used for the clock | ||
− | *Low | + | *Low sid Driver Chip -- but any transistors with reasonable beta and enough current handling capacity could be substuited. |
*Case -- With a bit more work than I have done you could have a really nice case. I am working on an oak one now | *Case -- With a bit more work than I have done you could have a really nice case. I am working on an oak one now | ||
*Clock Face -- Some good artwork here could make a really good looking clock, anyone willing to send me an high quality graphics file? | *Clock Face -- Some good artwork here could make a really good looking clock, anyone willing to send me an high quality graphics file? | ||
*Circuit Board -- Right now mine is built mostly on a proto board, but I have designed but not tested printed circuit boards suitable for single sided, toner transfer, fabrication. | *Circuit Board -- Right now mine is built mostly on a proto board, but I have designed but not tested printed circuit boards suitable for single sided, toner transfer, fabrication. | ||
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=== Features === | === Features === | ||
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|-valign="top" | |-valign="top" | ||
|Special effects -- Dancing | |Special effects -- Dancing | ||
− | |Hour and minute hands may "dance" at special times, see the video at: | + | |Hour and minute hands may "dance" at special times, see the video at: xxx |
<!--------------------------------> | <!--------------------------------> | ||
|-valign="top" | |-valign="top" | ||
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|For debugging and demo of special effects | |For debugging and demo of special effects | ||
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<!-------------------------------- | <!-------------------------------- | ||
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|} | |} | ||
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=== Circuit === | === Circuit === | ||
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To make it really easy to fabricate the printed circuit boards I seperated the power supply from the processor board. | To make it really easy to fabricate the printed circuit boards I seperated the power supply from the processor board. | ||
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==== Power Supply ==== | ==== Power Supply ==== | ||
− | This is a straight forward half wave rectifier with a linear regulator. It is powered by a wall wart transformer rated at about 9 volts. The unregulated voltage is over 9 volts ( 9 * ( 2 ^ 1/2 )) by simple theory. This unregulated voltage is used directly by the steppers so choose you wall wart to match your stepper motors. You should also size the filter caps based on the current that will be used by the motors. A couple of volts of ripple is not a problem as long as you have enough overhead for the 5 volt regulator ( the PIC might run on less, let me know if you try it ). An important part of the power supply is a 60 hz, roughly square wave. It is clipped off from the AC input. The 60 Hz power line tends to be very accurate over the long term, less so if you suffer power outages. You could run the clock on | + | This is a straight forward half wave rectifier with a linear regulator. It is powered by a wall wart transformer rated at about 9 volts. The unregulated voltage is over 9 volts ( 9 * ( 2 ^ 1/2 )) by simple theory. This unregulated voltage is used directly by the steppers so choose you wall wart to match your stepper motors. You should also size the filter caps based on the current that will be used by the motors. A couple of volts of ripple is not a problem as long as you have enough overhead for the 5 volt regulator ( the PIC might run on less, let me know if you try it ). An important part of the power supply is a 60 hz, roughly square wave. It is clipped off from the AC input. The 60 Hz power line tends to be very accurate over the long term, less so if you suffer power outages. You could run the clock on DC but the motors load down a battery pretty badly and you would need a timing signal ( the original code has a subroutine for timing off the crystal ). |
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Parts | Parts | ||
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|Part | |Part | ||
|Details | |Details | ||
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|-valign="top" | |-valign="top" | ||
|Wall Wart | |Wall Wart | ||
− | |You need one with AC output to get the 60 Hz timing signal from the power line. Mine is a 9 v 800 ma unit. I found it somewhere | + | |You need one with AC output to get the 60 Hz timing signal from the power line. Mine is a 9 v 800 ma unit. I found it somewhere. |
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|-valign="top" | |-valign="top" | ||
− | | | + | |Rectifier Diode |
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− | | | + | |Filter Caps |
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|-valign="top" | |-valign="top" | ||
− | | | + | |High Frequency Bypass |
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|-valign="top" | |-valign="top" | ||
− | | | + | |Clipping Diodes |
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==== Processor Board ==== | ==== Processor Board ==== | ||
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|Wall Wart | |Wall Wart | ||
− | |You need one with AC output to get the 60 Hz timing signal from the power line. Mine is a 9 v 800 ma unit. I found it somewhere | + | |You need one with AC output to get the 60 Hz timing signal from the power line. Mine is a 9 v 800 ma unit. I found it somewhere. |
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|-valign="top" | |-valign="top" | ||
|PIC16F877A | |PIC16F877A | ||
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− | | | + | |Low Side Switch |
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|-valign="top" | |-valign="top" | ||
− | | | + | |Rotery Switch |
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− | | | + | |Single Pole double throw Momentry Switch |
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− | | | + | |Pull Up/Down Resistors |
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|} | |} | ||
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=== Program === | === Program === | ||
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Nothing very fancy here. The 60 Hz input is fed to the port x interrupt. This lets the PIC keep time. The hands are not moved during the interrupt instead flags requesting hand movement are set and the main loop moves the hands. | Nothing very fancy here. The 60 Hz input is fed to the port x interrupt. This lets the PIC keep time. The hands are not moved during the interrupt instead flags requesting hand movement are set and the main loop moves the hands. | ||
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Invalid states for the mode can easily happen with a rotory switch when the wiper is not fully in position. Because of this not all possible states on the mode input are used. | Invalid states for the mode can easily happen with a rotory switch when the wiper is not fully in position. Because of this not all possible states on the mode input are used. | ||
− | The stepper control is half step. The activation of the coils is determined by an array which hold the 8 different activations of the coils | + | The stepper control is half step. The activation of the coils is determined by an array which hold the 8 different activations of the coils. |
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− | + | For the serial interface code see [[Serial Communications Library -- BoostC and 16F877A]] | |
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=== Additional Ideas === | === Additional Ideas === | ||
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*Add battery backup to keep the internal time ( but not the hands ) running during a black out. | *Add battery backup to keep the internal time ( but not the hands ) running during a black out. | ||
− | *Make it really big | + | *Make it really big. |
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− | + | === Download === | |
− | + | Comming, email me until then see [[russ_hensel] | |
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=== Comment, Questions, Contributions? === | === Comment, Questions, Contributions? === | ||
Email me [[russ_hensel]], or use the talk page for this topic. All feedback is welcome. | Email me [[russ_hensel]], or use the talk page for this topic. All feedback is welcome. | ||
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