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Trigger an Arduino board via USB

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Offline ahull

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Re: Trigger an Arduino board via USB
« Reply #30 on: 15 / September / 2013, 16:26:05 »
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How can i connect an external battery to the camera?

You need the following.

1) A dummy battery to fit in the place of the NB-5L (assuming I am correct in saying that the SX230HS uses an NB-5L)
2) A suitable external source of power, something that can supply  a nominal 3.7V  Actually you can get away with anything between between about 3.2 Volts and 4.2 Volts, since that is the range from flat to fully charged of the NB-5L, but  it must be capable of supplying up to around 2.5 Amps (from my experience, 2A would probably be sufficient).

There is a somewhat long winded thread about this here. but it distils down to what I have described above.
Actually there are a number of other threads on similar subjects, but most of the long windedness in that one is my fault  :D
The dummy battery is included in a lot of cheap clones of Canon's ACK-DC30 (the legitimate Canon power supply for those cameras that use the NB-5L) for example here. I would suggest you use the dummy battery and snip off the power lead from one of these, to use as a connector you your external battery (and throw the actual power supply as far away as possible, as they are somewhat poor quality). Pictures of a similar build including buck regulator module are here

... so my supplementary question really is, how long must the battery or external power source last between charges? Based on the answer to this, I can probably make some recommendations.

Obviously if you also intend powering the Arduino, your external battery pack  will need to supply +5V at whatever current your Arduino draws, probably around 50mA.
« Last Edit: 15 / September / 2013, 17:22:12 by ahull »

Re: Trigger an Arduino board via USB
« Reply #31 on: 15 / September / 2013, 17:22:27 »
So the right way is dummy battery.

For external power source no problem :-) 3.7V is a cell of a LiPo. I've a ton of batteries for my rc planes and exacopter so i can dismount a cell from some old pack or, from the balance connector, extract the 3.7V.

Thank you!


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Offline ahull

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Re: Trigger an Arduino board via USB
« Reply #32 on: 15 / September / 2013, 17:35:26 »
3.7V runs the camera, but you may need some other source to run the Arduino.


Re: Trigger an Arduino board via USB
« Reply #33 on: 16 / September / 2013, 04:39:29 »
On the plane I've a 3S 5A battery to power directly motor, autopilot and Arduino. But on the battery there's alaso a balance connector where i can extract the voltage of only one cell... I want to use it to power the camera.


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Offline ahull

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Re: Trigger an Arduino board via USB
« Reply #34 on: 16 / September / 2013, 14:05:00 »
On the plane I've a 3S 5A battery to power directly motor, autopilot and Arduino. But on the battery there's alaso a balance connector where i can extract the voltage of only one cell... I want to use it to power the camera.

Perfect, and if you can tap off at 7.2V and feed that to the regulator on the arduino, assuming it has a regulator, then problem solved.   :D

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Offline lapser

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Re: Trigger an Arduino board via USB
« Reply #35 on: 16 / September / 2013, 14:41:24 »
On the plane I've a 3S 5A battery to power directly motor, autopilot and Arduino. But on the battery there's alaso a balance connector where i can extract the voltage of only one cell... I want to use it to power the camera.
Perfect, and if you can tap off at 7.2V and feed that to the regulator on the arduino, assuming it has a regulator, then problem solved.   :D
Do you really need an external camera battery? My SX260 and D20 last about 1.5 to 2 hours on the internal battery. Then you don't have the problem of losing all the pictures when the external battery dies.

I also have a display off function in my CHDK mods that turns the display off completely, and saves 15 or 20 percent battery power. Does your plane stay in the air more than an hour?

What's the Arduino doing besides sending pulses to the camera and logging the time of each pulse?  With my time lapse script and set_shot_interval(), the accuracy of the interval is better than 1 msec. If you know the start time offset, you know the time of each picture very accurately. Also, if a picture misses the exact interval, the camera can still log the precise time the picture was actually taken.
EOS-M3_120f / SX50_100b / SX260_101a / G1X_100g / D20_100b
https://www.youtube.com/user/DrLapser/videos

Re: Trigger an Arduino board via USB
« Reply #36 on: 17 / September / 2013, 05:09:07 »
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Perfect, and if you can tap off at 7.2V and feed that to the regulator on the arduino, assuming it has a regulator, then problem solved.   :D
Yep, there's a regulator on board

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Do you really need an external camera battery? My SX260 and D20 last about 1.5 to 2 hours on the internal battery. Then you don't have the problem of losing all the pictures when the external battery dies.
The plane flies for half an hour but if you shot every 2 sec for 20 min I have to record around 600 pictures, I suppose too much for the battery.

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I also have a display off function in my CHDK mods that turns the display off completely, and saves 15 or 20 percent battery power. Does your plane stay in the air more than an hour?

I'd like to do the same thing... :-) can you explain to me how to do this? Some idea to switch on/off the camera?

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What's the Arduino doing besides sending pulses to the camera and logging the time of each pulse?
I've an IMU (3 axixs), GPS, Barometer and Magnetometer on board. I log every parameter on a SD card.



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Offline ahull

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Re: Trigger an Arduino board via USB
« Reply #37 on: 17 / September / 2013, 09:17:48 »
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Perfect, and if you can tap off at 7.2V and feed that to the regulator on the arduino, assuming it has a regulator, then problem solved.   :D
Yep, there's a regulator on board

Quote
Do you really need an external camera battery? My SX260 and D20 last about 1.5 to 2 hours on the internal battery. Then you don't have the problem of losing all the pictures when the external battery dies.
The plane flies for half an hour but if you shot every 2 sec for 20 min I have to record around 600 pictures, I suppose too much for the battery.

Quote
I also have a display off function in my CHDK mods that turns the display off completely, and saves 15 or 20 percent battery power. Does your plane stay in the air more than an hour?

I'd like to do the same thing... :-) can you explain to me how to do this? Some idea to switch on/off the camera?

Quote
What's the Arduino doing besides sending pulses to the camera and logging the time of each pulse?
I've an IMU (3 axixs), GPS, Barometer and Magnetometer on board. I log every parameter on a SD card.

One small point, the camera might flatten the cell to which it is attached significantly quicker than the rest of the cells, and thus cut your flight short. If this is the case, then you might be better using one of the cheap buck regulator modules fed from full pack voltage, and set for 4.2V or so for the camera. this would be at the expense of a few grams more weight of course. The Arduino regulator *should* be able to cope with the 13V or so direct from the pack, but check this with the Aduino documentation.


Re: Trigger an Arduino board via USB
« Reply #38 on: 17 / September / 2013, 10:47:43 »
Thank you for the right observation.
I'll measure the current absorbed from the camera and then I'll decide for a new regulator or a dedicated cell.


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Offline ahull

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Re: Trigger an Arduino board via USB
« Reply #39 on: 17 / September / 2013, 11:14:04 »
I look forward to seeing some of the results.  :D As a very rough guide, a typical camera uses round 100 - 200 mA when it is sitting idle, less with with the display off, more and perhaps as much as 2A when moving the lens and focusing, so it may represent a significant draw.
« Last Edit: 17 / September / 2013, 11:16:53 by ahull »

 

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