The 100 best digital picture frames on amazon
The 100 best digital picture frames on amazon
The 100 best digital picture frames on amazon
The 100 best digital picture frames on amazon

How to get rid of the blink­ing rain­bow square on your Rasp­berry Pi pic­ture frame

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Do you have a slow­ly flash­ing 1 cm rain­bow square in the top right cor­ner of your Rasp­berry Pi pow­ered dig­i­tal pic­ture frame? This is your computer's way of say­ing that there is a prob­lem with the pow­er sup­ply. Here is how to fix it.

It hap­pened one day

A few years ago, I built two iden­ti­cal dig­i­tal pic­ture frames with a Rasp­berry Pi 2B+. I used a Rydges 2A/5V pow­er sup­ply which came with a four-star Ama­zon review aver­age and an attached mini USB cable.

About three years lat­er, I noticed a col­ored square in the upper right cor­ner of the screen, which on occa­sion, fad­ed in and out very soft­ly. It was about a cen­time­ter in size. Then it was gone for weeks, came back for a few min­utes, and was gone again.

I start­ed think­ing that my screen was about to expire. As there was no reg­u­lar­i­ty to the appear­ance of the mul­ti-col­or square, and I had nev­er come across a sim­i­lar issue, I was clue­less first.

But, as always, a lit­tle Inter­net research will go a long way.

It turned out that the com­mon­ly called rain­bow square was an under­volt­age warn­ing. It meant that the pow­er sup­ply did not pro­vide the required pow­er any­more. The sig­nal is trig­gered at 4.75V.

But why was every­thing fine for three years and then with­out any hard­ware or soft­ware change, from one day to the oth­er, it wasn't?

The slow and painful death of pow­er sup­plies

The answer is that pow­er sup­plies can lose pow­er over time. The good ones are not sup­posed to, but I guess the $10 USB pow­er sup­plies for our Rasp­berry Pi are not exact­ly rat­ed mil­i­tary grade and can dete­ri­o­rate over time.

Inter­est­ing­ly enough, the oth­er dig­i­tal pic­ture frame which I built at the same time and with the same com­po­nents also start­ed to dis­play the same symp­toms a few months after the first. So it wasn't an iso­lat­ed inci­dent.

When read­ing up on the sub­ject, I found that pow­er sup­ply degra­da­tion is often the result of high tem­per­a­tures and a per­for­mance reduc­tion of about 20% is not unheard of.

The pow­er sup­ply was glued to the met­al back of the bare dis­play, but the IPS dis­play did not get very warm, and nei­ther did the pow­er sup­ply. But it didn't get a lot of ven­ti­la­tion either.

What I found inter­est­ing was the grad­u­al­i­ty of the degra­da­tion. We are used to dig­i­tal com­po­nents, either work­ing or not, but my pow­er sup­ply was fight­ing death for almost six months.

At first, I saw the rain­bow square appear only a few short sec­onds, then noth­ing for weeks, and then a few times dai­ly. In the end, it stayed on per­ma­nent­ly.

By the way, dur­ing all these months, I didn't notice any oth­er tech­ni­cal issue with my Rasp­berry Pi. Every­thing was work­ing as before.

How to fix it the right way

Should your Rasp­berry Pi dig­i­tal pic­ture frame show the same symp­toms, then it's time for a new pow­er sup­ply.

But choose wise­ly as the Rasp­berry Pi pow­er require­ments have increased with the lat­est mod­els.

While the Rasp­berry 2B+ was hap­py with 2A, the lat­est mod­el from June 2019, the Rasp­berry Pi 4 demands 3A.

But it's not just the pow­er sup­ply. It's also the cable.

In my case, the cable with a mini USB plug was firm­ly attached to the pow­er sup­ply, so I did not have a choice.

How­ev­er, should you get a pow­er sup­ply with a detach­able cable, don't skimp on the cable. The thick­ness of the cable is prob­a­bly a good indi­ca­tion of its qual­i­ty. You can lose a lot of per­for­mance with a bad cable. How­ev­er, unlike a pow­er sup­ply, I don't think a pow­er cable will degrade over time.

How to wing it

If every­thing else works fine and it's just the rain­bow square which keeps appear­ing in your pho­tos, then you may be able to pro­lon­gate the remain­ing life of your pow­er sup­ply by telling your Rasp­berry Pi to ignore under­volt­age and stop pes­ter­ing you about it.

A dig­i­tal pic­ture frame is no mis­­­sion-crit­i­­cal appli­ca­tion (although my wife and sis­ter would beg to dif­fer) so you can try the fol­low­ing:

ssh into your Rasp­berry Pi

ssh@your-IP-address

Then

cd /boot/
nano config.txt

Go to the end of config.txt and add the line

avoid_warnings=1

Save, reboot, and the rain­bow square should be gone.

Mind you, if you expe­ri­ence strange behav­ior with your Rasp­berry Pi, then it is indeed time to get a new pow­er sup­ply. You will be sur­prised how many "unex­plain­able" issues can be traced back to an inad­e­quate PSU.