Last Minute Power Supply

In this blog, we talk about a recent photography project turned into a power supply building frenzy.

New to us, the project involved some product photography work. With no experience, the team scrambled to assemble light box, staff brought in their own camera from home. While we thought we have everything ready, we noticed nowadays digital cameras do not come with AC power supply. This is absurd!

After carefully checking each camera, we found building our own power supply would be the cheapest and fastest. Here is what we did, hope you find this useful.

Remember from our previous blog, we recently upgraded some computers and the ATX power supply would do a good job but first let’s take a look at some specs.

Nikon Coolpix CP8700 and EN-EL1 battery

This Li-Ion battery is rated 7.4V with 850mAh capacity. A fully charged EN-EL1 has 8.4V, the user manual says the battery last 210 shots (Standard Nikon test conditions: monitor on, zoom adjusted with each shot, flash used about once every three shots, image quality set to Normal)

Nikon EH-53 AC Adapter (US$25 on eBay)

This AC Adapter is the official power supply compatible with the Nikon Coolpix CP8700, it has a rated output of DC8.4V at 1.3A.

Since we need to get a power supply giving us similar output to the EH-53, we need to look for older type ATX power supply. Look for one built prior to ‘ATX12 version 1.2 standard’, the 20-pin or 24-pin connect will have a -5V (White wire) at Pin 20. Read the label on the side to determine cable coloring scheme and voltages. In our scenario, we need power supply that has +3.3V (Orange wires) at 28A and -5V (White wire) at 0.5A, this will give us ~8.3V.

Reference :

Follow the Phil’s (@jumperone) ATX power supply tutorial and properly prepare the power supply, this includes grouping the wires and terminating them. Clean the supply with compress air, make sure the cooling fan is operation while you have the case opened.

Once we identified the cables, especially the +3.3V and -5V. We are to extend it so that it can reach the camera and terminate it will a DC plug. Determining the plug size will take some trial and error since no documentation on EH-53 and Nikon Coolpix CP8700 show the correct size of the DC plug. Our measurement indicated 1.7mm DC plug will fit perfectly.

A quick hooked up and we have success! The Nikon is powered up and stayed on. We quickly soldered everything up, heat shrink tubing all joints and it’s done!

Total time needed = 20 minutes.

Enjoy, Team BTF

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