I then decided to design this new circuit, this time very simple, which doesn't need any microcontroller, is connected to an IR remote (mine is for Olympus Camedia bridge camera, but you can find similar ones for almost any compact and DSLR camera) and it includes a simple voltage regulator only to supply the IR remote control. Digital camera should need its own PSU (or battery, but it should be a very powerful one for a timelapse). So the TIRR was born!
Step 1: Intro
Step 2: The remote
Step 3: Choose the box
For my timelapse circuit I've decided that one of these transparent boxes from Muji could be very appropriate. The shop has various sizes of these containers, and I've found a model which is the right size to keep 4 AA batteries inside, plus a little rectangular circuit.
Step 4: Refine it
If you have already a cool box, of any type, you should design the pcb for that size.
Step 5: A little of theory
I want that my circuit activates the shot button for an istant and repeat this every certain period until battery discharges or I turn off everything, and the interval between shots should be customizable. Actually there are three resistances in the variable circuit because R1 appears to be the sum of two of them. With some simple calculations I've retrieved the right values for the three resistances. I've used Tspace for the contact time and Tmark for the interval, indeed if you check the formulas with R1 variable between 2.2K and about 102K (2.2K+100K) and R2 equal to 470ohm you'll find that Tspace turns out to be 0.3 second fixed and Tmark varies from about 2 seconds to about 70 seconds. It's very rare to make timelapses with more than 70 seconds between shots because with that time also slow clowds will appear to move too fast in the final video.
You can see the circuit in action with Falstad applet. It doesn't work very good in simulation (pheraps because seconds are too much long time intervals for this simulator) but my circuit works well.
Here you have the components list, note that I already had some of them (as the variable resistor), so I chose these, but maybe you can find a different combination of values.
100 kohm variable resistor (better logarithmic)
10 nF ceramic
10V 1000 uF electrolytic
an optocoupler PC817 (but probably also a NPN transistor as the PN2222A is good)
an IC NE555
a 3.3V voltage regulator L78L33 (with two not essentials capacitors, one 100 nF and the other 330 nF)
a battery holder, better with wires
and a switch
Step 6: The voltage regulator
Here I've tested the operation of this chip, of course it works great! You can check if IR LED turns on simply looking it through your cellphone camera, or any digital camera with a display.
Step 7: I love routing...
In Fritzing you could design your circuit on a breadboard, and then arrange your components on a pcb. You can draw your traces or let the program auto-route them.
This is the image of the finished pcb. The program will print for you the pdf with routes to etch (pay attention to choose the right one, Fritzing makes for you the mirrored image too). Pdf is handy because you don't have to worry about print's measures. I've retouched the image and added some identical circuit on the same sheet so you can keep them in reserve.
Step 8: Toner transfer tecnique: printing...
You need an old iron (mine is new but I'm trying to make it old very fast), a laser printer and some sheets of right paper. To know if your paper is right you have to try it. They also sell some dedicated paper which should be perfect, but maybe you wish to try with some magazines. In my case it worked well. I suggest to clean very well the copper board with a steel spunge. Then clean with alchool both the board and the printed side of the paper.
Step 9: ...ironing...
Now, it's VERY IMPORTANT you always keep a cotton dish-cloth or something similar between iron and paper, unless you'll ruin iron steel surface. With iron head pass on the back of the paper so that the toner acts as glue, then remove tape which otherwise should damage your iron surface (yes, it's very weak to scratches). Now press your paper hardly with iron at max temperature, wait 2 or 3 seconds, and make it again, trying not to burn the dish-cloth and your cotton ironing board, or anything you've used as base.
Now let everything cool down and then, paying attention to not blend the paper sheet (which otherwise comes off taking toner with him), put everything in cold water and let it get soften.
Step 10: ...removing paper...
Step 11: ...checking traces...
Step 12: ...preparing etching...
Step 13: ...dipping into acid...
Keep windows open because the process makes some fumes, and I think they're not much healthy.
After about 30-40 minutes (in my case, but you could have a different etching duration) you could take out your pcb and clean it from acid with paper and then a lot of water.
Step 14: ...cleaning and checking...
I've obtained a good (but not perfect) result, as you see in picture. There are some border traces with a lot of cracks, but they should work the same, in doubt let's test them with the multimeter. If you observe carefully you also see a little unexpected connection between two traces, let't break it with a cutter.
Step 15: ...and drilling
It's time to make the holes. With your column drill (which of course you have built following my Instructable) choose the right size of bit (I use usually 1mm, but bigger for potentiometer anchoring holes) and carefully drill every hole. Pay attention to not detach the copper routes.
Step 16: Circuit comes alive
I don't teach you how to solder because I'm a bumbler in that, I strongly recommend you to follow Dave's soldering tutorials on EEVBlog.com.
To choose right LED (I mean the LED I liked more) I've connected a temporary socket... it was an hard choice, had I said you that I felt in love with my first 3mm red LED when I was 10 years old? ;-)
After that, I soldered the LED with short pins to diffuse the light over the transparent surface of the box.
Step 17: Does it work?
Step 18: Let's finish the case
I've used some elastics taken from a bike tube to keep everything closed, because I've already cutted the locking mechanism of this box for another project. Then I've glued the IR remote on the back side of the box, lettig the wires come out from some slots cutted in the side. Of course also switch and knob need their holes.