Time Lapse Intervalometer for SLRs with 555 timer IC

Step 5: Final test and limitations

Look it works!

Ice melting is boring, so I made sure it was a quick frame rate.
What can you use this for?

Limitations
Ok, so you get what you pay for sometimes. If you went with a manufactured intervalometer, you would get a accurate interval setting. This isn't quite so accurate unless you put a knob on it or something. There is also another slight problem. The camera counts away or a desired length, the "off" time, and then fires off the shutter, the "on" time. It seems that this "on" time can sometimes be too short for the camera to register. Because of this, it sometimes misses pictures. As long as this happens not too often, no big deal I guess. There has to be a solution to this in the circuit that can extend the output pulse, but it's way over my head. I welcome your help on this problem.
Also the buttons don't work while the circuit is on. It would be nice to focus or take extra pictures while the timer is running. Any ideas on that are welcome too.

Comments

[KipperFillets]

I've got a Nikon D70, which doesn't have a connector for triggering the shutter, and I certainly don't want to cut it open. Therefore I built a circuit to trigger a Nikon remote control (or actually a £1.50 ebay look-alike). I don't even have to have a lead connected to the camera.

[sgt_rock]

I would love to see the D70 circuit. I'm trying to automate a D70S,a D40X and a D50, but the seem to react intermittenlty.

[douglas braid]

this looks good for my project ,I will try to twaek a shorter time than 30 seconds thanks

[Mother Natures Son]

What do you use to put the images together into video?

[Mark Rehorst]

Great project! The camera "debounces" the shutter button closure by requiring that the switch remain closed for some minimum amount of time, typically >20ms. It will vary from camera to camera, so using the longer time will be more reliable. You can improve your circuit by using a 556 which is two 555s in one package. Set one up as an monostable that produces 20 or 30 ms pulses (or even longer- 100 ms won't hurt), and run the other as an astable that triggers the monostable. This whole thing could be implemented with better reliability, more functionality, and fewer parts using a 6 or 8 pin PIC uC. I would also recommend using a relay at the output instead of a transistor. A relay will provide universal compatibility and will not be subject to destruction by static discharge. Something like a PRMA1A05 has a 500 Ohms coil and works at 5V. For a minimal investment of about $20 you can get a PicKit2 programmer from Microchip that will program and even debug a lot of their chips. The software to go with it is a free download from their web site. Once you start programming for a project like this, you'll think of all sorts of features you can add simply by changing the program. TD

[Swishercutter]

Relays add "bounce" to the output. If you use TTL logic type transistors (mainly just not FET's) you should have very little problem with static (same with the 555). It is mainly things with MOS at the end that are static sensitive, not all the time but for the most part. Not all solid state is static destructive, also it depends on what leads you touch on the static sensitive devices. It is always best to assume everything is static sensitive though since partial static destruction can lead to failure at a later date (sometimes it just weakens the junction). It is doubtful that you would ever encounter a current problem since the output transistor is just sinking the current to ground, plus for the pulse time most discrete form transistors can handle plenty more current than any camera would ever source. (it would be stupid for a camera company to use large currents for a shutter switch since it would severely limit battery life)

[Mark Rehorst]

The input of the camera is designed for a mechanical switch closure so contact bounce is not an issue. Long cables can generate significant static charges when dragged across a floor, especially a carpet, or even from coiling and uncoiling. Protection from static electricity is ALWAYS a good idea. I prefer to spend $2 for a relay and do it right from the beginning instead of spending a couple hours removing a dead transistor and replacing it with a relay later. A relay is universally compatible, not because of current drain but because of polarity. Do you use a PNP or NPN transistor? Will it work for EVERY camera? Are you SURE? With a relay there is no uncertainty. It WILL work with EVERY camera and there will be no need to keep track of the wires coming out of the camera. It won't matter which is ground and which is "high" or "low". Simpler, more reliable operation is always good. TD

[Swishercutter]

Correct, a relay will work fine. No doubt there, but when you talk reliability (contact wear, etc), power conservation (coils use more) and complexity solid state is better. I don't really want to argue something that is correct either way its just a matter of preference. Plus, in this circuit you would have to drive the relay with a transistor anyways (that would be best). To add a relay to this circuit I would connect the relay coil (+) to the (+) side of the voltage source and then the relay coil (-) to the output of the transistor then just wire the camera to the load side of the relay. (BTW, if you want a bidirectional there is always the solid state relay.)

[Swishercutter]

I also forgot the back emf diode. If you are using a relay driven by any solid state device (555 timer or transistor) you must connect a 1N4148 diode to the coil side of the relay. It would be installed with the cathode facing the (+) side and the anode connected to the (-) side of the coil. This shunts the inductive kick around the sensitive components.

See herehere

[toekneebullard]

May I suggest you make an instructable with these adjustments? I'm interested in building this, but if there's a more efficient and reliable way...

[eagleapex]

I definitely want to learn how to program a PIC, so when I do, you'll see it here.

[toekneebullard]

I didn't mean you eaglepex, I figured since Tyler had so much knowledge on the subject he could do a different one.

[Mark Rehorst]

I'm finishing up a crossed IR beam camera trigger with some higher speed intervalometer functionality. I will write it up when it's done. Right now I am using a 6 pin PIC10F206 but will be changing to an 8 pin PIC12FHV215. Hardware is 90% done and programming for the 6 pin uC is done. Only minor changes will be required to convert to the 8 pin uC. I will probably finish this week if I can free some time from studying head and neck anatomy. TD

[Mark Rehorst]

Work on the crossed beam photo trigger is done! I'll be writing an instructable on it shortly. I stayed with the 10F206 because it looked like the 12HV215 part was not really a good idea after all. TD

[eagleapex]

Thanks TD, the 555 was a little buggy and I think a PIC is the obvious upgrade. I'm just not at the knowledge level to start programming one though. I'll get there soon and make another instructable. How about a program that only takes pictures at night? or increases the frequency after every shot. It would be cool.

[Swishercutter]

I believe you could lengthen your output pulse by changing either the .1uf to a larger value, or by changing the 33k to a higher value.

Someone correct me if I am wrong please but I believe the output charges the .1uf cap with an RC time constant of 3.3ms (.1u x 33k=.0033).

So therefore a 200k resistor in place of the 33k would give you the 20ms shutter time. (.020 \ .1u=200k).

This is an excellent write up. I will build this soon. There will be a few addons but the basics of this are very sound.

With very little modification this could be made to focus before shuttering also. Even if you had to go as far as to add a sample and hold circuit, but I think it can be done with minor modifications to the circuit with just capacitors and resistors.

[bahgheera]

Hi, thanks for the great instructable. Now to business - can anyone help me with this? I've got a pulse at the emitter of the transistor, but for some reason it's not triggering the shutter of my Canon Rebel XSi. I know the cable is wired correctly - the switch works and brushing the wires of the cable together triggers the shutter, but the transistor just won't do it. Probably because of the debounce circuit in the camera. So how would I go about lengthening the pulse? Could I increase the size of one of the caps?

[viniciuspedrozo]

Sale to me !