Help!!! What is this and how do we get rid ?!?

I managed to zoom right in and get this pic... It's a lot smaller in real life, I'd say 1-2mm big. Just visible when you have a bright light on them and up close!! We have a lot gathering on the wall near the skirting board in the bedroom... We have had a problem with damp/mould! Could it be to do with that?? We've found them on our phones (we leave them on charge on the floor by the bed of a night) and on xbox controllers etc. Makes my skin crawl and we just need to know what they are and a solution! If anyone knows it would be a great help!!