"Trosik" with a timer for digital cameras Canon
It is no secret that when shooting at long exposures of the photographer, a tripod and a control panel (“cable”) save. If the tripod can be purchased almost everywhere, and there are quite good models costing even 600-700 rubles, then things are not so rosy with the remote control. The price tag on Canon proprietary consoles starts at $ 30, and meanwhile within this remote contains only the simplest switching circuit. To shoot a time-lapse video, you will have to purchase a remote with a timer (the Canon brand is $ 210, the Chinese brothers in reason are cheaper). I want to show how without the use of sophisticated electronics and controllers you can independently assemble a functional “cable” with a timer that fits Canon cameras of the EOS-300D / 350D / 400D / 450D series and maybe some other.
Let's start with a simple, but probably this is enough for someone. For the usual "cable" button, you will need two buttons, one switch, a jack-plug with a diameter of 2.5 mm and a wire (I took the old wire from a computer mouse). They need to be connected as shown in the diagram below. In the same place, what part of the plug is connected to.
Here, S1 and S2 - buttons, shooting occurs when holding the "Auto Focus" click "Shutter". S3 - switch, closes the autofocus circuit, and allows you to shoot simply by pressing the trigger.
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You can buy a case for this device (like this one ), but you can show imagination and collect it in an egg from “Kinder-surprise” or a box from “Tik-tak” (I had exactly this):
But we will not stop at a simple remote, but add a timer to it and combine everything into one device. The timer task is to “press” the trigger once every certain number of seconds. Obviously, a device known to all can close the contacts with an external signal: a relay . But in order to reduce the device and increase reliability, we apply the optorele. I used KR293KP2A due to low control voltage and current (only 1.3V / 5mA), cheapness and size.
It remains to deal with the control circuit for the relay. The best solution would be a square pulse generator with a period equal to the period of shooting that we set. Such a generator can be assembled on individual transistors, and chips can be used. I was just lying around the NE555 single-chip micro-circuit (I have a datasheet, for example, here ) and I decided to use it.
The datasheet shows the reference scheme of the pulse generator, and we will collect it. The complete scheme of the entire device is shown in Figure 2. In this embodiment, the U1 chip works as a multivibrator. Figure 1 shows a graph of the generated pulses.
Figure 1 - Graph of generated pulses
The period t1 corresponds to the charging time of the capacitor C1, the period t2 corresponds to the time of its discharge. The first trick we'll go for is about the inverter. More precisely his absence. From the graph it is clear that almost all the time the shutter release button will be “pressed”. But if you set a single-shot mode on the camera, then after the leading edge of the pulse (and therefore the triggering of the optorele), the shutter “clicks”, and after the exposure time, the mirror will snap into place. The reset time of the t2 camera is enough to start waiting for the next click. The battery in this use case is consumed in the same way as in the usual manual shooting.
The datasheet provides formulas for calculating t1 and t2. Since C1 is charged through the chain R3 and R1, the period t1 = 0.693 * (R1 + R3) * C1. The period t2, corresponding to the discharge through R1, is 0.693 * R1 * C1. It is clear that we can adjust the time by changing the resistance value R3. Given the normal values of the timer from 1 to 70 seconds, we obtain, taking into account the existing element ratings, the resistance and capacitance values shown on the diagram. It is worth noting that when installing R3 to the extreme position corresponding to zero, the generation failed, so I had to enter R2 of a very small resistance and it all worked.
Since the optorele is controlled by a voltage not exceeding 1.5V and a current of 5-10mA, we will assemble the corresponding voltage divider for R4 and R5. It is calculated taking into account the fact that when the supply voltage is 9V at the output of the multivibrator, the signal voltage will be about 7V (according to data from the datasheet).
Figure 2 - Complete device diagram
The second trick is associated with the union of two "cables" into one. First, in order for the timer to “press” the trigger, the autofocus latch must be turned on. Secondly, there is no sense in supplying power to the timer when it is not really needed. Therefore, I used a two-way switch S3. In the top position, it simply turns on the autofocus, while the voltage to the circuit is not supplied due to the diode D1. In the lower position, both the autofocus circuit and the timer power supply circuit are simultaneously closed. Please note that the power supply of the timer is electrically isolated from the autofocus circuit, despite the fact that “+” voltages are supplied via the same wire as the “ground” of the camera, as they have different “ground”.
It remains to put everything together, carefully checking the connections (I soldered the circuit on the circuit board, cutting a square of 3x3 cm from it). The case of scrap materials here will be harder to pick up, so I bought a ready-made case with a battery compartment. The result was such a device:
In development plans: add a timer power indicator and try to make a photosynchronizer - add a circuit with a phototransistor on the case to the shutter button (this will help to remove, for example, a zipper). Well, in the end, to replace most of the stuffing with a microcontroller with information output on the display and with greater accuracy and a range of specified time.
Simple control panel
Let's start with a simple, but probably this is enough for someone. For the usual "cable" button, you will need two buttons, one switch, a jack-plug with a diameter of 2.5 mm and a wire (I took the old wire from a computer mouse). They need to be connected as shown in the diagram below. In the same place, what part of the plug is connected to.
Here, S1 and S2 - buttons, shooting occurs when holding the "Auto Focus" click "Shutter". S3 - switch, closes the autofocus circuit, and allows you to shoot simply by pressing the trigger.
')
You can buy a case for this device (like this one ), but you can show imagination and collect it in an egg from “Kinder-surprise” or a box from “Tik-tak” (I had exactly this):
Control panel with timer
But we will not stop at a simple remote, but add a timer to it and combine everything into one device. The timer task is to “press” the trigger once every certain number of seconds. Obviously, a device known to all can close the contacts with an external signal: a relay . But in order to reduce the device and increase reliability, we apply the optorele. I used KR293KP2A due to low control voltage and current (only 1.3V / 5mA), cheapness and size.
It remains to deal with the control circuit for the relay. The best solution would be a square pulse generator with a period equal to the period of shooting that we set. Such a generator can be assembled on individual transistors, and chips can be used. I was just lying around the NE555 single-chip micro-circuit (I have a datasheet, for example, here ) and I decided to use it.
The datasheet shows the reference scheme of the pulse generator, and we will collect it. The complete scheme of the entire device is shown in Figure 2. In this embodiment, the U1 chip works as a multivibrator. Figure 1 shows a graph of the generated pulses.
Figure 1 - Graph of generated pulses
The period t1 corresponds to the charging time of the capacitor C1, the period t2 corresponds to the time of its discharge. The first trick we'll go for is about the inverter. More precisely his absence. From the graph it is clear that almost all the time the shutter release button will be “pressed”. But if you set a single-shot mode on the camera, then after the leading edge of the pulse (and therefore the triggering of the optorele), the shutter “clicks”, and after the exposure time, the mirror will snap into place. The reset time of the t2 camera is enough to start waiting for the next click. The battery in this use case is consumed in the same way as in the usual manual shooting.
The datasheet provides formulas for calculating t1 and t2. Since C1 is charged through the chain R3 and R1, the period t1 = 0.693 * (R1 + R3) * C1. The period t2, corresponding to the discharge through R1, is 0.693 * R1 * C1. It is clear that we can adjust the time by changing the resistance value R3. Given the normal values of the timer from 1 to 70 seconds, we obtain, taking into account the existing element ratings, the resistance and capacitance values shown on the diagram. It is worth noting that when installing R3 to the extreme position corresponding to zero, the generation failed, so I had to enter R2 of a very small resistance and it all worked.
Since the optorele is controlled by a voltage not exceeding 1.5V and a current of 5-10mA, we will assemble the corresponding voltage divider for R4 and R5. It is calculated taking into account the fact that when the supply voltage is 9V at the output of the multivibrator, the signal voltage will be about 7V (according to data from the datasheet).
Figure 2 - Complete device diagram
The second trick is associated with the union of two "cables" into one. First, in order for the timer to “press” the trigger, the autofocus latch must be turned on. Secondly, there is no sense in supplying power to the timer when it is not really needed. Therefore, I used a two-way switch S3. In the top position, it simply turns on the autofocus, while the voltage to the circuit is not supplied due to the diode D1. In the lower position, both the autofocus circuit and the timer power supply circuit are simultaneously closed. Please note that the power supply of the timer is electrically isolated from the autofocus circuit, despite the fact that “+” voltages are supplied via the same wire as the “ground” of the camera, as they have different “ground”.
It remains to put everything together, carefully checking the connections (I soldered the circuit on the circuit board, cutting a square of 3x3 cm from it). The case of scrap materials here will be harder to pick up, so I bought a ready-made case with a battery compartment. The result was such a device:
In development plans: add a timer power indicator and try to make a photosynchronizer - add a circuit with a phototransistor on the case to the shutter button (this will help to remove, for example, a zipper). Well, in the end, to replace most of the stuffing with a microcontroller with information output on the display and with greater accuracy and a range of specified time.
Source: https://habr.com/ru/post/112920/
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