• 1x Atmega 168 or smaller chip with Arduino bootloader preprogrammed (the code compiled is only 4k)
• 1x 28-pin IC socket (so that you can use chip for other projects latter)
• 1x 16MhZ ceramic resonator
• 1x 16×2 lcd display, HD44780 compatible
• 1x 7805 5V voltage regulator
• 4x micro buttons
• 1x SFH615 optocouppler
• 2x 3mm led diodes (green for power and yellow for activity)
• 4x 220R resistors, 1x 10K resistor and 1x 1K resistor
• 2x trim potentiometers (4K7 and 10K)
• 3x male headers(6-pin, 3-pin and 2-pin)
• 3x ceramic capacitators(0.1 uF, 1uF, 10uF)
• 1x 3.5 mm female jack for connection to laser

Now this post wouldn’t be complete without Eagle schematic and board files. You can download them on the following link: Trigger schematics (395).

I don’t have schematics of the laser side because it’s simple. I’m leading 3 wires with 3.5mm audio cable, analog in, gnd and vcc(+5V). In the laser box I have laser which is connected directly to the vcc and gnd, one foto resistor that is giving to high value to analog in so I have one resistor before it connected to gnd.

So we have:

• GND wire is connected to laser gnd wire and to one side of let’s say 2M resistor which other side is connected to one leg of photo resistor
• VCC wire is connected to laser vcc wire
• Analog in wire connected to other leg of the photo resistor

It depends on which photo resistor you are using how big resistor value before it you have to use. Arduino is capable of reading analog in until value of 1024 and that’s reason why the big resistor value is needed, so you are testing which one do you need until the value of direct laser beam to the photo resistor is under 1024, mine is about 920.

The soldering was OK with only few places to be fixed because of strong acid mix, but nothing special.

Here are some pictures of the finished trigger.

P.S. This is final and last prototype of the version 1. The next one will be better, without trimpots, with 3-4 keys, lot of menus and few outputs instead of one.

Stay tuned!!

• removed triggering 3.5mm female connector, instead I have 3-pin connectors to connect wires on one or two flashes
• added 6 pin programming header so that I can program Atmega chip without removing it from the board every time
• added 3 pin jumper header for power selection (usb/external)

Here are two pictures of a fresh etched board, not perfect on the corners because of bad mixing of the acid but good enough for the first attempt.

P.S. Updated schema coming soon.

And here it is, description, schematics, video and sample pictures.

The idea has already been seen on the Internet. Arduino is controlling photo resistor on which laser beam is pointed. When resistance changes itself because of the drop that is cutting beam then Arduino is triggering Nikon camera after the amount of time specified with one trim capacitor which can be between 0 and 1023, but I have divided it with 2 so that I have better control of the delay. All information is displayed on 2×16 LCD display. Also to be able to take picture of drops colliding it’s necessary that speed of the drops be 10 drops/sec so I have implemented one button for that with proper code behind it.

I have also 4 buttons and 2 led diodes on the board. Buttons that I have are reset for resetting of the electronics, debug that is switching debug mode on and off, drops that is designed to count drops per second and ready button that is used when I’m taking pictures so that when drops are falling fast I don’t trigger camera every time when they are going down. Led diodes that I’m using are green for power and yellow for visual notification when the trigger is trigged.

Here is the final schematics that I’m using right now.

Nikon-Arduino trigger schema

For simplified solution with cables I’m using standard audio cables with 3.5mm stereo jacks on both sides, so I can use same cables for other purposes as well. I have also modified Nikon cable remote so that it has 3.5mm female stereo jack built in for simple use with trigger and without it.

Modified Nikon cable release

Here are few pictures of the whole setup.

Nikon Trigger

Of course code behind is in this NikonFastTrigger.pde (343) file available for download.

Simple instructions.

1. when the program is loaded it will display Ready on the second line
2. when drop breaks laser beam then instead of Ready on display will be Busy until you press Ready button
3. offten because I have laser box about 1m above the surface delay is needed between 150-220 ms

For drops counter I’m doing like this.

1. switch to drops counter with drops button
2. then I try to create drops stream with about 1 drop per second with help of the normal digital watch and by changing delay I set Arduino to recognize that as 1drop/sec
3. now the only thing left is to configure drops stream to 10 drops/second for colliding watterdrops

Here are couple of pictures captured with this setup and pictures of colliding drops are to come.

And here is the video from YouTube.

Because some of them doesn’t work on my HU I had first to build Arduino scanner to scan for those missing remote codes.

Although I’m sending codes as binaries it was easier for me to work with decimals on the serial console and then latter convert them to binary so I have wrote function for that as well.

Because the first part of signal is always the same there was not need to convert it at all, and it’s stored in variable iHello, so the part that is changed is the second part or 3 decimal numbers.

Now because there are 255*255*255 = 16 581 375 possible combinations I had to bring this to some reasonable number otherwise it would take very much time to find right codes so I have limited combinations a bit.

I took the lowest and the highest values from codes from link above for the first and the second decimals, and limited the third one to 2 possible numbers that I’m sending as finish 85 or 213.

Here are those codes that I have founded working on my HU:

1. 87  253   85 ( 01010111  11111101  01010101 ) – Pause
2. 107 247   85 ( 01101011  11110111  01010101 ) – Band/ta
3. 111  237   85 ( 01101111  11101101  01010101 ) – Defeat
4. 119 235   85 ( 01110111  11101011  01010101 ) – Power
5. 173 238 213 ( 10101101  11101110  11010101 ) – Mute
6. 183 219   85 ( 10101101  11101110  11010101 ) – Source
7. 187 218 213 ( 10111011  11011010  11010101 ) – Next Track
8. 93  250 213 ( 01011101  11111010  11010101 ) – Previous track
9. 219 214 213 ( 11011011  11010110  11010101 ) – Volume up
10. 109 246 213 ( 01101101  11110110  11010101 ) – Volume down
11. 171 239 85 ( 10101011  11101111  01010101 ) – Folder/memory up
12. 85 255 85   ( 01010101  11111111  01010101 ) – Folder/Memory down

Now because I have IR remote for my HU and defeat is not on it I assume that it’s possible to find even more codes for it but I didn’t those so I stopped here where I have everything for my first project.

Here are pictures of the interface that I have built for testing of codes. It consists of 5 buttons which have been assigned different functions and 3.5 mm female audio jack which I use for connection with HU. HU has the same 3.5 mm female jack on the back so I can use regular 3.5mm stereo cable for testing without any modifications on HU or Arduino board.

Here is the Arduino Alpine scanner (408) sketch file with all functions that I have used for scanning, saving and displaying codes on serial console.

Here are the instructions how to use this sketch to find codes.

1. First you need to erase eeprom with erase function to be sure that it’s clean on the start of scan.
2. Now comment out function for erase and uncomment function for saving combination on eeprom
3. Now you are ready for scan, so when you connect Arduino to your HU just press button 4 to start scan
4. When you see some change on HU you need to press button 4 to stop scan
5. Using buttons 1 and 3 you can go back or forward to find that combination that you discovered
6. When you find it you can verify it with button 2 which repeats it again
7. If that is combination that you are looking fore press button 5 to save it to eeprom
8. When you have found all combinations that you are interested of connect Arduino to computer and on serial console you will have all combinations that you have found, so copy and paste them in iFounded array
9. Comment out functions for saving, previous and next button and uncomment functions for import of combinations, sending of previous and next combinations
10. Now when you power up Arduino press button nr 5 to import combinations and cycle them with buttons 1 or 2 to confirm that you have right combinations saved

Now when I have all of the codes needed to control HU I can finish the first project and the post about it is coming soon.

Any comments are welcome.

Alpine CDE-9880R

Now because I have original HU controls on steering wheel, instead of buying an adapter I thought that I could build one.

The first idea that I have is to build RF remote that would be controlled by PIC and controls on steering wheel.

I will try to see if this is possible to do or look for another solution.