This instructable started with my previous camera hack making a remote shutter release. I found a 555 timer tutorial and realized how great it would be to automate my pictures and do some time lapse photography. I'm not too great with making electronics from scratch, so my friend Michelle helped out a lot with the planning of the schematic.
I found a great guide to time lapse photography that covers all the details before and after this Instructable. They mention the use of an "intervalometer" (a new word to me) which can cost $60 to $150 dollars. That's way too expensive for the casual photographer I think. So I made my own!
I found a great guide to time lapse photography that covers all the details before and after this Instructable. They mention the use of an "intervalometer" (a new word to me) which can cost $60 to $150 dollars. That's way too expensive for the casual photographer I think. So I made my own!
Remove these ads by
Signing UpStep 1: Planning, Schematic, Materials
Below is a schematic that I made with free schematic software from ExpressPCB. You can also download the .sch file if you want to edit it. Remember, that won't get you a PCB to burn, only a schematic to mess around with.
Here's what this circuit will do. When you turn it on, the camera will get a false signal and take a picture. Then the big capacitor will slowly fill with charge while the green LED is on. How slowly is chosen by the variable resistor. When the cap discharges, the 555 outputs a signal to the transistor which connects the shutter control to ground. The red LED lights up and the camera takes a picture
Repeat.
There are also buttons to use the box as a remote shutter release when the circuit is off.
As you can see you need some stuff. Here's a list:
Materials
Resistors: 100k, 470k, 33k, and one 1M variable
Capacitors: 220µF, 0.1µF
LED's: Green, Red
Transistors: NPN-type switching
555 IC timer chip
IC holder socket (to switch out a bad chip)
Protoboard and then later a Radioshack IC PC Board
9V battery
On/Off switch
Momentary buttons,
Battery clip
For Pentax DSLRs, Canon Rebel's, and maybe some others:
Cell phone headset with 3/32" 3 conductor plug (make sure it works, but go cheap)
Extra wires
Project box
Soldering and wire stripping tools and such
Cost:
555IC: $1.69
IC PC Board: $2.49
Handsfree headset kit: ~$5
Other bits and bobs: ~$10
So it all can be had for under $20 and some effort.
Here's what this circuit will do. When you turn it on, the camera will get a false signal and take a picture. Then the big capacitor will slowly fill with charge while the green LED is on. How slowly is chosen by the variable resistor. When the cap discharges, the 555 outputs a signal to the transistor which connects the shutter control to ground. The red LED lights up and the camera takes a picture
Repeat.
There are also buttons to use the box as a remote shutter release when the circuit is off.
As you can see you need some stuff. Here's a list:
Materials
Resistors: 100k, 470k, 33k, and one 1M variable
Capacitors: 220µF, 0.1µF
LED's: Green, Red
Transistors: NPN-type switching
555 IC timer chip
IC holder socket (to switch out a bad chip)
Protoboard and then later a Radioshack IC PC Board
9V battery
On/Off switch
Momentary buttons,
Battery clip
For Pentax DSLRs, Canon Rebel's, and maybe some others:
Cell phone headset with 3/32" 3 conductor plug (make sure it works, but go cheap)
Extra wires
Project box
Soldering and wire stripping tools and such
Cost:
555IC: $1.69
IC PC Board: $2.49
Handsfree headset kit: ~$5
Other bits and bobs: ~$10
So it all can be had for under $20 and some effort.
schematic.zip8 KB
Visit Our Store »
Go Pro Today »
I noticed you didn't follow the "standard" astable 555 timer circuit (http://www.eleinmec.com/article.asp?3). Is this because of the allowable values for R1, R2, and C? If not, wouldn't it be simpler to go with the standard circuit with a very large capacitor value and a properly selected R2?
By the way, wouldn't it also be easier to guarantee an activation pulse of >20ms as suggested by tyler below simply by changing the values of the second (reset) pair of RC?
I'm still reading up on this stuff, so please let me know if I'm wrong.
Here is my take on your circuit. It uses the 555 the way God intended, in the standard astable configuration. The "on" time is determined strictly by the values of C2 and R1, using the formulas given in the link in my first comment (in this case 0.15s) so there is little chance of missed shots. The wait time is determined by the values of R1, R2, C2, and the variable resistor R3, so the max value can be modified by using different resistor values.
http://dl.dropbox.com/u/3845046/intervalometer.png
The entire lower half can be ignored, it is a driver for the red/green bicolor LED from Radio Shack to indicate power on (red) and timer pulse (green). Other arrangements would have to be made if using a different LED, or a pair of LEDs. (Note that the diodes in the LED driver are zener diodes, intended to be used "backwards".) I used a standard audio mini jack so you can just use an mini audio cable instead of having to hack up a cell phone head set.
I eventually got so far as to design and etch a small single sided board to implement this circuit using SMD parts. It all works great. I have the board available in Eagle format if anyone wants it.
I agree a relay would be preferable, but transistors are cheap and low power.
The issue isn't needing to buy a new costly transistor (hehe...) , it's more like - who wants to rip it apart and replace one when it does get pooched?
Relays can be found everywhere to salvage. Particularly old computer modem cards - they each have 2 on them, from what I've seen.
Hmm, well if the schematic works for you I guess, carry on!
SMD is cool too. I'd prefer simple separate LEds for on/off too.
What do you think?
Individual red/green LEDs could be used, just drive one with a PNP transistor and the other with an NPN, with current limiting resistors. Or more easily, you could just replace LED1 with a pair of LEDs back to back (that is all the red/green Radio Shack bicolor LED is, in one package).
Probably the simplest way to add in manual focus and trigger buttons would be to place them across the connections on the audio jack itself. Then you would use the main power switch to shut off the circuit and use the buttons as a manual trigger.
I never addressed the hardest part of any project like this, which is the casing. Having all the elements be board mounted makes for easy assembly, but makes finding or assembling a suitable case much harder. If I were going to case it, I would probably use panel mount switches, LEDs, and jack.
This makes a great "first project" for anyone getting into electronics. I learned how to read circuit diagrams, read data sheets, schematic capture, board layout, home etching, how to order parts online, and through hole and SMD soldering. If I were to do it today, I would do something with a microcontroller.
This makes a good first project for electronic diy'ers and also teaches you about 555 timers and saves money for a photographer.
I built one of these myself with a similar design (not the same though) that is MUCH improved over this one and without errors in it. I could start an instructable with the instructions/parts list, schematic and a link to buy the board from me.
I ask because I designed a board for my intervalometer, and figured people new to electronics might prefer that over perf board.
I'd make the PCBs myself and would sell them for $5 or so each (depending on how long it takes me to drill them)
If there's enough interest I can whip up a batch of 6 or 7 of them and get working on an instructable :)
Cheers!
As it stands, I don't have the time right now unless there's some profit in it for me unfortunately. I am struggling enough to do some part time work while I'm in school! :(
Thanks for the response though. Maybe more will tune in!
- The schematic shows the potentiometer wired at the two ends of the resistor. One of the leads needs to go to the center tap instead (otherwise it's just a 1M resistor).
- I took swishercutter's advice about increasing the value of the 33k resistor to make the pulse longer. Thank you, this solved my non-trigger problem.
- I added a 22uf capacitor in parallel with the 220uf cap and a switch to choose between them. This gives me a selectable range of about 3 to 30 seconds with the 22uf and 30 seconds to 4:30 minutes with the 220uf cap.
- The LEDs I used have resistors built in, so I didn't use the 470k resistors.
- I mounted it in a Altoids tin, it looks cool that way.
Picture on flickr: intervalometer
monostable: http://www.technologystudent.com/elec1/5553.htm
astable: http://www.technologystudent.com/elec1/5552.htm