Radio Controlled Stopwatch

As a teacher and member of various sporting organisations, I have observed various different timing systems, from the traditional stand-alone stopwatches to more sophisticated (and very expensive) co-ordinated systems that simultaneously time, then record race data. The system is still under construction. I have commenced writing this Instructable early as I have already discovered some pitfalls and shortcuts!.

Step 1: Equipment - Shopping List

Starter GUN Transmitter

• nRF24L01 2.4GHz Radio/Wireless Transceivers.
• Arduino Uno
• Wii gun controller with momentary button attached
• 12 volt piezo speaker+ voltage booster
• camera flash +opto-coupler
• Five AAA rechargeable batteries
• enclosure + jumpers + protoboard , 10uF capacitor
• capacitor 47 uF capacitor .33 uF 3.3 volt regulator

Six Identical Receiver Stopwatches

• Arduino Uno
• momentary stop button
• reset button (can't be knocked mid-race!)
• 16 x 2 LCD module
• 5 permanent AAA rechargeable batteries.
• on/off barrel key switch (can't be switched off mid-race!)
• Red LED (RSSI indicator) 330 ohm resistor
• enclosure + jumpers + protoboard (see above) lanyardeye bolt

• nRF24L01 2.4GHz Radio/Wireless Transceivers

Step 2: Prepare Radios and Attach to Uno

NEED:

• breadboard with a momentary switch
• all equipment from step 1
• soldering equipment and lots of different coloured wires
• male headers (optional if not using jumpers)
• all equipment from step one.

1. go to maniacbug and read all preliminary info on 2.4 ghz radios.
2. On both radios, solder all coloured wires (or cut off jumpers with male end attached) onto radio module headers - try and use maniacbug colour coding above.
   • HINT: Check for short circuits
   • HINT: Attach 10uf capacitor to VCC and Gnd, close as possible to the radio- check polarity.
3. Set up breadboard and attach momentary button to digital pin 7 and 10 k pullup resistor to gnd. Attach 5v to other side of momentary switch. Diagram.
   • HINT: To ensure button works Try running the arduino 'button' sketch before adding radio module
4. Attach radio headers onto UNO. Pin allocations are:
   • Pin 9 orange
   • Pin 10 yellow
   • Pin 11 blue
   • Pin 12 violet
   • Pin 13 green
   • Gnd black
   • 3.3v red

Step 3: Attach the Receiver/Stopwatch

Use this guide to Solder wires onto LCD shield .

Hint: Pins 4, 5, 6, 7, 8, 9 do not need any soldering but should be checked with a multimeter to ensure that the pins are correct for the sketches you'll use. eg On pin 4, check continuity from arduino pin 4 to D4 on LCD. Some modules don't have the same pin allocations as the way I have stated below...

• Pin 3 RADIO CE (orange) solder onto LCD shield
• Pin 4 LCD D4 pin to digital pin 4
• Pin 5 LCD D5 pin to digital pin 5
• Pin 6 LCD D6 pin to digital pin 6
• Pin 7 LCD D7 pin to digital pin 7
• Pin 8 LCD RS pin to digital pin 8
• Pin 9 LCD Enable pin to digital pin 9
• Pin 10 RADIO CSN (Yellow) solder onto LCD shield
• Pin 11 RADIO SCK (Green) solder onto LCD shield
• Pin 12 RADIO MOSI (Blue) solder onto LCD shield
• Pin 13 RADIO MISO (Violet) solder onto LCD shield
• 5 Volt Momentary "Stop" button with 10k pullup resist or to Gnd
• Gnd RADIO GND (black) solder onto LCD shield.
• A1 proto button on breadboard. attach 10K resistor to earth side of button.
• 3.3 Volt RADIO VCC (red)
• HINT: DO NOT CONNECT 5 v TO RADIO!!!!
• HINT: 5volt VCC not needed for prototyping.
• HINT: Hardwire the momentary button to a GND rail on a proto board, ready to go into enclosure.

Comments

[threiner]

do u havw the sketches ??

[andrewsayer22]

Hi

This looks like a great gadget! Have you got any photos of the final product? Could a guy with no RF experience and average electronic skills make this??

thanks!

[MsSweetSatisfaction]

Woah awesome gadget! Welcome to instructables!