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Race Start Audio

demo 1

demo 2*

*Note: - Demo 2 "Countdown" is truncated - the verbal 10 second calls at 50, 40, 30 and at 20 seconds have been omitted.

 

Click here for the full C.M.Y.C. Audio .wav ZIP FILE [308Kb]

Two Tracks

  1. "Boats to the Water"

  2. "At the Mark" - a 60 second countdown

Voice: Di Ballantyne

______

PC Board, Hand Book, and pre-recorded ISD chip available $(NZ)40.00

as at 20/09/04

ADDITIONAL

NOTES

IF RECORDING YOUR OWN CHIP USING THE ABOVE wav FILES.

1: It is best if you devise a means of recording direct to the chip via a wired patch rather than with a "speaker to mike" link.

2: Make sure that when laying down the second track that you continue recording after the track is completed until the capacity of the chip is full. Otherwise the automatic "Return to Start" will not function.

I used a graphic display on the PC to cue up the tracks - press RECORD for the chip then immediately PLAY on the PC, being ready to hit RECORD/PAUSE for the chip again on Track One's completion.

Cue up Track Two on the PC and repeat the process but this time let the chip run on (one or two seconds) after playback is finished to fill the chip's capacity.

This means that the entire capacity of the chip is used to contain the two discreet tracks and has a "Stop" mark inserted between them.

 

MORE NOTES

1: On the circuit board there are nine wire links (caused mainly by my inexperience in designing such things) which need to be located and understood - don't miss the one beneath the ISD itself. The diode below the ISD from the voltage regulator is unneccesasary and could be replaced as a tenth link. Click here for photo of the ten links and three diodes.

2: Do use a 28 pin IC mount on the board as it is likely the ISD chip will be inserted and withdrawn a number of times.

3: When connecting up the RESET and START switches be very careful not to mix-up the wiring connections as the timing 556 works at 12 volts and the ISD at 5 volts!

4: On the component overlay diagram there has been a change with the wiring yoke pins and sockets - originally I had the male pins on the wires - they are actually on the PC Board and the sockets are on the wires. (05/07/04)

A DIGITAL RACE STARTING UNIT

CHRISTCHURCH MODEL YACHT CLUB

CANTERBURY J CLASS ASSOCIATION

 January 2004 (Last up-dated 25 March 2006 ~ John Hutchings' "TRex")

NOTE ~ Some diagrams opened in your browser may look very spidery and incomplete - you will find that they print out O.K. but do print off from the larger picture, not the thumbnails!

March 2006 - John Hutchings of Trenton, Ontario, has made a most impressive red thunderbox (below right) with some simplification and an auto battery saver addition (Click here for details)

 

 

Most model yachting clubs probably rely on the humble cassette tape recorder to provide the disciplined countdown to begin their races. This carries with it three distinct disadvantages:

    1) Poor amplification unless an expensive 'Ghetto Blaster' is used, and this is in time likely to be stolen from the pond side.

    2) The annoying needs to rewind and cue up the tape.

    3) Poor weather protection.

At the Christchurch Model Yacht Club frequent comment was often made, "There must be a more simple way!" I was commissioned to discover it! What follows does not claim to be original, but is offered to assist any other club that would like to build a self contained digital "START BOX". Thoughts were first directed to CD type players and then I discovered the ''CHIPCORDER" digital chip produced by "Voice Solutions in Silicon" <http://www.isd.com/> which allows for up to two minutes of message recording within a solid state device - no tapes - no CDs!

These 'ISD' chips retail for around (NZ)$45.00 and are available as 28 pinned, flat devices around the size of a large postage stamp - they are available with various recording times (i.e. 40, 60, 75, 90, and 120 second duration) and virtually last for life!

I based our prototype Start Box (right) on the ISD 2575 that has a 75-second recording time. This allows for a five second call, "Boats to the water" and a sixty-five second "One Minute Countdown" sequence. Successive pushes of the START button initiate each 'track' in turn. The system automatically returns to the beginning of "Boats to the Water" after the countdown is complete. The countdown can be paused and restarted or the entire sequence cancelled and reset at any time. A simple ten-watt audio amplifier based upon the TDA2003 audio chip boosts the output of the ISD to an adequate level from two six watt speakers - my wife, to her embarrassment, can hear it from a kilometre away (to her embarrassment? - it is her voice on the countdown!). A small twelve-volt 'Gel-cell' powers the unit. (Download CMYC .wav files)

The prototype unit has worked well now for twelve months with the only hitch being an inability for some members to remember that electronic units do required to be switched OFF when put away - fortunately we run two batteries!

 

 THE MARK 2 STARTING UNIT

The Mark 2 unit (picture at top of page) now to be described differs from the prototype by the addition of an "Auto 60" switched position which requires only the one push of the START button to initiate the complete sequence, automatically starting the countdown sixty seconds after the Call to the Water.

A manual switched position is retained whereby, as on the prototype, the O.D. controls the period between the Call to the Water and the beginning of the Countdown sequence. As can be seen the cabinet and the control panel also differ with the Mk 2.

Given a couple of enthusiastic members, one with some cabinet making and metal turning skills and another with electronic know-how, the project would present little difficulty for a club to produce.

 

 

THE ELECTRONIC SIDE:Not too sure how these circuit schematic files will turn out - expect some refining over the next few weeks.

 

 

 

 

NOTE - with the ISD chip all unconnected pins (chiefly the recording and AGC circuitry) are left floating.

There are four external controls viz.

  1. A MODE switch (OFF, Manual, and Auto 60)

  2. A VOLUME CONTOL

  3. A large (green) START button

  4. A smaller (orange) RESET button

The circuit involves four distinct modules laid out on one board with five four-terminal connectors for the control leads viz.

  1. A Power In and Speaker Out, - 4 wires and a fuse.

  2. Audio Out and Audio In via the VOLUME CONTROL, - 2 shielded (co-ax) wires.

  3. A switching loom to a 4 pole, three position MODE switch to give OFF, Manual, and Auto 60, - 3 wires. The fourth pole could provide for an LED "ON" light.

  4. A twin lead to the START / PAUSE button, - 4 wires.

  5. A twin lead to the STOP / RESET button, - 4 wires.

 

 

MODULE ONE: ~ The Ten-Watt Amplifier:

Developed for car audio systems the TDA2003 chip requires the minimum of components to provide a very stable 10W audio amplifier.

Speaker loading is 4 ohms - though our Mk 2 is loading into two 4" 4 ohm, 6 watt speakers connected in series. You might choose to opt for one 4ohm speaker of larger power handling capacity

The input is fed from the ISD chip via a 50K-log potentiometer.

 

 

MODULE TWO: ~ The ISD Recorder chip:

See http://www.winbond-usa.com/products/isd_products/chipcorder/datasheets/index.shtml for detailed circuitry - (scroll down to the ISD2560 data and download the relevant .pdf data files)

OZITRONICS at http://www.ozitronics.com/ can provide a great little experimental kit (K146) using the IRD chip (specify a 75 second one) at a very reasonable price, and with a great mail-order and help service!

John Hutchings links a great kit outfit at http://qkits.com/ who can supply ISD kits and audio amp.)

On our Mk 2 circuit board the recording components and the Record/Play switching have been omitted which means the construction of another complete ISD board to record the chip (or get a pre-recorded one from me). To be noted is the necessity to include a voltage regulator component to drop the 12-volt supply to 5 volts.

The START / PAUSE button connects pin 23 momentarily to ground and the STOP / RESET button connects pin 24 momentarily to V+.

 

MODULE THREE: ~ The "Auto 60" timing circuit:

This is a fairly conventional circuit arranged around the proverbial NE556 timing chip. The 556 is equivalent to two NE555s, the first circuit is set for a sixty-five second cycle and the second circuit gives a short positive pulse at the end of that cycle to actuate a relay and so simulate the second push of the START / PAUSE button of the ISD. The relay is necessary to isolate the two circuits because of the voltage difference (12V on the timer and 5V on the ISD).

 

MODULE FOUR: ~ The "Timer Running" bleeper

During the sixty seconds from the end of the Call to the Water and the start of the Count-down, an audible 'bleep' is emitted from the unit around every four seconds.

 

MODULES Three and Four are only connected to the V+ supply when the MODE switch is at "Auto 60".

 

COMPONENT OVERLAY:

Click on thumbnail for larger diagram

and for a photo, click on thumbnail for a larger picture

 I have printed circuit boards available at (NZ)$30.00.

 email me if interested in purchasing.

 

TRACK SIDE:

Click on thumbnail for larger diagram. Track layout updated 8 March 04 - larger component holes and thicker tracks - photo should come out at correct size but enlarge/shrink in photocopier if neccessary until chip holes align with actual component.)

 

WIRING CONNECTIONS:

I have used mini pcboard connectors to allow the heavier switch components to be mounted before the pcboard is installed in the cabinet as the push button switches need to be screwed into the heavy duty plungers. Click here for a diagram of how to wire things up.

 

THE METAL WORK SIDE:

There is a need to make a couple of robust push-buttons for START and RESET as the commercial articles are either too small and fragile or too expensive. A commercial two-pole, Momentarily ON switch is screwed to the bottom of a brass button unit which itself takes the brunt of heavy handiness. The accompanying diagram shows the idea in principal and the actual detail and size would be according to materials available to the builder. The push buttons are sprung loaded and the commercial switch is screwed in just sufficiently to close with full movement of the push button. Both units are identical in size except that the START button cap could be significantly larger than the RESET button. Click here to see photo of parts.

To be constructed as well will be aluminium bracketing to hold the circuit boards and a battery holder of some sort. (How you connect the battery is up to you - spades will eventually come adrift. I made spring loaded contacts to engage the battery terminals of the particular battery type used.)

 

THE CABINET WORK SIDE: Everyone (I hope) will have their own ideas for this but click here for a very incomplete plan/sketch of our Mark II design. It is best to build up the electronics first and then build a cabinet to fit. Don't forget a hatch on the back to get things in and out especially important for an easy battery exchange.

 

The author would appreciate FEEDBACK and progress reports from any one building this unit so that common queries or difficulties can be addressed. Click on the URL below to email me.

Simon Ballantyne ~ stball@paradise.net.nz