Creating and testing the electronics

The final circuit diagram

The circuit will end up looking something like this (click on the image to enlarge)

2016 update – A couple of clubs have written to me with problems which we have tracked down to problems in the GND circuit (including Stuart at Stalybrindge CC.  In several builds, this has been because clubs have used separate 12v and 5v power supplies.  You must use a master 12v  PSU with a 5 volt step down which is powered from the 12v adapter.  I also recommend that the Arduino is also powered from the same 12v adapter.  This way they key electronics components all share the same 12v GND (negative) circuit.  Teams that have used separate power supplies for 5v and 12v have had trouble with the digits working reliably.

Sergio at Pontinia CC in Italy has a much better understanding of how the shifters work.  He has come up with a slight modification to the circuit design, and I have updated the design on this page to reflect it.  Thanks also to John from Tabard RFC for testing and confirming the new circuit design is sound.

Building the circuit.

Start with the stripboard, and using a 3mm drill, gently drill out 9 of the copper strips in the middle of the board.  This stops the legs of the Shifter from being shorted.

IMG_0158 IMG_0160

Insert the IC DIP20 module on to the strip board, with the pins at the top (by the u shaped semi circle) in the first row to have been drilled.  This means the last set of pins should still be connected by a strip of copper.  Solder the DIP20 on to the strip board.  For help on soldering, check out the links page, soldering on strip boards is probably easier than you think!

IMG_0162 IMG_0163

Add the capacitor to the circuit board.  It should be between the SRCLR and G strips.  Bend the pins so they touch the copper strips and solder them on (see circuit layout below).

IMG_0164   

Now add lengths of cable of around 20 cm to each of the legs of the DIP20 socket, and solder them in (using the diagram above).  Once all of the soldering is done, you can insert the Shifter IC in to the DIP20 socket (make sure the U shape on top of the IC is inserted in to the same end as the U shape on the DIP20 socket).  It should end up looking something like this.

IMG_0167

it is very sensible to label each of the cables with a piece of masking tape, it really helps when you test.

Do this 15 times and you are done!

Testing the Circuits

Set out a 7 segment display on some cardboard, and apply some 12V power.  Should look something like this…..

IMG_0145

digitLayout

Cut the negative wires between light modules, and ensure there is a continuous positive circuit.  The light modules are numbered like this (note that these are numbered as looking from the front (this is important, especially as you will be wiring them from the back and will need to do it in mirror!).

Add a second set of LED modules to the cardboard and repeat to create a second digit.  Then using crocodile clips (or by twisting the wires together) wire up two circuits boards, using the following scheme.

Source Destination
Circuit board 1 12v + Positive input on left set of LED modules (looking from front)
12v – Circuit board GND
5V + Circuit board VCC and SRCLR (both)
Pin 2 on Arduino Circuit board SRCK
Pin 3 on Arduino Circuit board SERIN
Pin 4 on Arduino Circuit board RCK
Circuit board 0 LED Module 0 negative
Circuit board 1 LED Module 1 negative
Circuit board 2 LED Module 2 negative
Circuit board 3 LED Module 3 negative
Circuit board 4 LED Module 4 negative
Circuit board 5 LED Module 5 negative
Circuit board 6 LED Module 6 negative
Circuit board SEROUT Circuit board 2 SERIN
Circuit board 2 12v + Positive input on right set of LED modules (looking from front)
12v – Circuit board GND
5V + Circuit board VCC and SRCLR (both)
Circuit board 1 SRCK Circuit board SRCK
Circuit board 1 RCK Circuit board RCK
Circuit board 0 LED Module 0 negative
Circuit board 1 LED Module 1 negative
Circuit board 2 LED Module 2 negative
Circuit board 3 LED Module 3 negative
Circuit board 4 LED Module 4 negative
Circuit board 5 LED Module 5 negative
Circuit board 6 LED Module 6 negative
Circuit board SEROUT Circuit board 3 SERIN (and so on)

Please note that the digits are wired for left to right (as you look from the front).  The top line of digits (Bat A, Total and Bat B) is wired to pins 2 [SRCK], 3 [SERIN] and 4 [RCK] on the arduino, with pins 5 [SRCK], 6 [SERIN] and 7 [RCK] wired to the bottom line (Wickets, Overs, Target).

After installing the Arduino software on a laptop, upload the proto-pic counter sketch to the arduino.  Apply some power and you should see: