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Peltier cooler for DSLR
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Peltier cooler for DSLR

by betelgeuse91 on Thu Apr 25, 2019 9:53 pm

Hi, I am interested in making a DSLR cooler with this item: https://www.adafruit.com/product/1335

As I have limited power supply, I would like to add a controller that can manage power consumption.

So I came up with an LED dimmer like this one: https://www.amazon.ca/gp/product/B008TNH68E/ref=ox_sc_act_title_2?smid=A319D8OFIJWHG9&psc=1

I am worried that I heard that those LED dimmers use pulse width modulation (PWM) and this can cause radio frequency interference (RFI) that can affect the images.

Will this be bad for my DSLR camera?

Also, my battery will accept a c1garette plug. Then what components do I need from this cooler set, or from the LED dimmer to connect to a c1garette socket?

Thanks so much!

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Re: Peltier cooler for DSLR

by adafruit_support_mike on Fri Apr 26, 2019 2:48 am

PWM'd power to the Peltier module shouldn't have any effect on the camera it's cooling. There won't be any electrical connection between the Peltier and the camera, thermal response curves are a few orders of magnitude slower than electrical PWM, and I've never heard of DSLR cameras being sensitive to RF interference.

betelgeuse91 wrote:Also, my battery will accept a c1garette plug. Then what components do I need from this cooler set, or from the LED dimmer to connect to a c1garette socket?

To clarify, do you want to send power into the battery through the socket, or pull power out of the battery through the socket?

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Re: Peltier cooler for DSLR

by betelgeuse91 on Fri Apr 26, 2019 10:21 am

Hi Mike, thank you for your reply.

I want to draw the power out of my battery to run the cooler. My battery has small capacity, so if the peltier cooler constantly draws 5A at 12V as specified, it won't last for a long time. So I would like to modulate the power consumption.

For the RFI, I found the relavent information from a dew heater: https://www.astronomics.com/model-sdcc-two-channel-four-output-standard-dew-heater-controller.html?___SID=U

This dew heater uses PWM and in its description it emphasizes that it is RFI free, and that it is important for imaging. I don't know anything about RFI but after reading this, I was concerned that devices that use PWM might affect DSLR sensor... Do you think it should be irrelevant? (i hope it is, so I can use the LED dimmer with no problem)

Thanks..!

betelgeuse91
 
Posts: 3
Joined: Thu Apr 25, 2019 9:39 pm

Re: Peltier cooler for DSLR

by adafruit_support_mike on Sat Apr 27, 2019 3:11 am

I did some searching on the subject of RF interference with DSLR imagers, and saw a lot of speculation without much empirical testing to back it up.

There were a couple of images that showed low-level noise that looked like it has some structure. Those were ascribed to influence from a nearby cellphone but I didn’t see any positive claim that the phone was actually emitting RF signal when the image was taken.

It’s true that RF interference can generate a signal in anything conductive that’s within range, but that’s why the FCC exists. Anything that can generate a signal strong enough to disrupt other devices is either licensed or illegal.

You can mitigate the effects of emitted RF by using twisted-pair wiring between the PWM generator and the Peltier module. Equal current flowing in opposite directions through two interlocked and nearly identical helices cancels itself almost completely.


In terms of adding a 12V plug as an alternate power source, that depends heavily on the design of your battery pack. If it can accept input while powering a load, adding the connections should be fairly simple. If not, you’ll need a circuit that can keep two separate power sources from causing problems for each other.

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Re: Peltier cooler for DSLR

by betelgeuse91 on Sat Apr 27, 2019 9:48 am

I see... Thanks so much for your help!

betelgeuse91
 
Posts: 3
Joined: Thu Apr 25, 2019 9:39 pm

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