Showing posts from July, 2013

Monitor Temperatures on your phone with an Arduino

After using the Bluetooth link to connect to the Chronograph I thought I'd use it to remotely monitor some temperatures, mainly because my fridge was acting up.

I connected the BT interface to the Arduino (my own version), this is quite easy because you just connect the TX from the Arduino to the RX of the BT interface and the sketch just uses the serial.print command.  This means you can test it out on your PC using the serial console in the Arduino IDE.

For testing I just make a small sketch to continuously output two random temperatures.

long randNumber;
long randNumber1;
long randNumber2;
long randNumber3;

void setup() {

void loop() {
randNumber = random(5, 20);
randNumber1 = random(1, 10);
randNumber2 = random(5, 20);
randNumber3 = random(1, 10);

DIY Chronograph - Nokia display

The Acrylic case arrived on Saturday for the Chrono using the Nokia 5110 display.

I just wired up the display to an Arduino Mini Pro and put the case together to make sure it all fit together.

The Nokia display is on top, the battery on the bottom with the Arduino Mini Pro in the middle.
No I have to fashion a joystick extension, sort out a power switch, build up the sensor tube and figure out to re-charge the battery with out taking it all apart.
Sketch can be downloaded here. Sketchup and EPS files for the case are here.

DIY Chrono Shopping list

A few people have expressed interest in making a DIY chronograph so I said I'd put together a shopping list.

There are quite a few options for the display type so I try to give the pros and cons at each step.

Firstly, the processing power.
All my projects are done using the Arduino family, including the many clones out there, I've used original Arduinos and Clones from China all without any problems. (A PIC Micro will do just as well with the same hardware)

Arduino Mini Pro Arduino Nano

These are available in 5V 16MHz and 3.3V 8MHz versions, I used the 5V versions @ 16MHz to get the best uSecond resolution, I believe that the 5V versions can be run at 3.7V and still run at 16MHz. This device needs an external USB to serial adapter to allow programming but, once progr ammed, can be fed from a 7V source via the on-board regulator (RAW input) or a regulated 3.3 to 5V supply on the VCC pin. I bought mine on Ebay from here for less than £3 but it took 27 days to arrive. Others on Ebay sea…

Finally the DIY Chronograph meets Android

Yes, I finally got a Bluetooth serial adapter to connect to my Arduinos.

I bought it off Ebay for £5, just search for HC-06 Bluetooth adapter but be aware that it comes with and without the mounting PCB.  The one in the picture comes with the back PCB which handles the level shifting from 5 to 3.3V as the transceiver itself is 3.3V not 5V and the connections are a bit small and difficult to solder to.

The connections are 5V, GND, TX and RX, the baud rate comes set to 9600 but can be changed using a terminal console and AT commands also the name and pass code can be changed, the default pass code is 1234.

Once this was connected to my Arduino I put together a little sketch to simulate some shot data, a loop counting from 300 - 340 incrementing by one every 5 seconds (saved a lot of pellets ;-))

I've did attach the transceiver to the sensor tube (as seen in part6) for a quick trial with the pistol and it worked fine.
Next came a couple of days writing the Android app using the App I…