How to know if my work is worth a paper? I work in a computer science research lab as an engineer. I work in field A, but I got really fascinated by field B and I worked in my free time on an idea in field B.

I want to pursue a PhD in the end of my contract so I'm thinking about publishing results. So far, I have zero publication. I may get a chance to write a paper in field A, but if I can also in field B, I'd have better chances to get a PhD I like.

My question is : how do I get opinions about my work in field B?

I implemented a software which works, does not beat state of the art but has exciting potential in my opinion. I combine an old idea with a brand new idea. It's quite a lot of work and effort. I was thinking about presenting it in a blog and publishing the code in order to get feedback and become a bit more known (i'm done with all the figures and experiments). If it is a success, I wanted to write a paper (and publish in arXiv) straight after. I'm afraid that if the idea is good, I will be potentially missing out on citations which could help me become more known. Also, if I don't write a paper and just publish stuff on my blog, I don't prove that I "play by the rules" and that I can write properly, edit LaTeX, submit papers, etc... A third possibility would be to ask a researcher which is concerned by my project, show him what I did and talk with him before taking any initiative.

I don't want anything to interfere with my current work so I have not talked with the team here about my side work. We have been delayed quite a bit and I don't want to give the false impression that it's because of my side work.

What do you think?

edit: MJeffryes commented that arXiv is not a journal. Yes, I thought that at least, publishing in arXiv allows to get citations (whereas a blog cannot be cited, I guess), and then submit it to conferences/journals.
Talk to somebody in Field B! That's the best way. 

Make a contact. To find "the right somebody" to talk to, start by describing your idea very vaguely (so nobody steals your idea) to somebody you know and trust in that field, or who has an interest or connection to it. Tell them you're hoping to publish, and ask if they know anyone in Field B who knows more about the topic or might be willing to talk with you. Invariably, your friend will give you a name or two, and you can do the same with those contacts. Repeat until you find the right person. I've had great success in my university with this approach. 

Perhaps you could find somebody in Field B who would be willing to coauthor with you. They might even have funding to publish in a peer-reviewed journal, though that's a long shot. Publishing in a peer-reviewed journal would probably improve your visibility. 

Good luck! If you do get it published, cone back here and link to it. I'd love to see your idea.