Topic: [ANN] BitcoinSpinner - page 16. (Read 45071 times)

I've downloaded it and am trying it out now.

As a minimalist interface, it looks pretty good. There's not much extra going on anywhere in the app to seriously confuse people.

I sent coins to the app, and it correctly showed the amount "on their way". I had intended to keep it open to see if it automatically let me know when the transaction was confirmed, but got distracted and re-opened the app to see the coins in-hand, so to speak.

All in all, this looks like an excellent, wonderfully simple app that should be great for mass market use.

This is the reason for phonegap…it gives you access to things like the camera across all the devices it supports.  All the HTML&JavaScript are embedded in the app you download (not loaded from a server every time…although you could also do it that way).  And, since it is just HTML5+JavaScript, you could easily make a version that works with any web browser on any device (phone, tablet, laptop or otherwise).  You could bundle it as a downloadable app or deliver it from a website (but as you say, you have to trust the website every time you use the app instead of just once on download…although I've seen some proposals to deal with that as well (i.e. side loading the critical key handling code).

I haven't looked into phonegap, but I agree that HTML5 & JavaScript (or Dart) is the way to go, however I see two obstacles:
1. You are downloading the app on each use -> you have to trust the site you download it from.
2. You need access to the camera to scan QR codes, and I don't think this is possible on an iPhone

I don't really care about the mass markets, I care about me.

What I really want is a native app built using phonegap, HTML5 & JavaScript such that it's maximally portable.  Also, eventually Apple will allow these apps, especially when everyone is jailbreaking their phones to install them.

BitcoinSpinner is written in Java, and uses the BCCAPI which is also written in Java. To implement this for iPhone you would have to port the BCCAPI to C/C++ish languages, and implement the UI on top from scratch. This is not a big pile of work, but would take a seasoned developer some weeks. This big problem however is, as you indicate, that this would only be useable for jailbroken devices. So you would never hit the mass market.

Thanks for the feedback.

Regarding the fee: This is a limitation of the server implementation and not the App as such, or in other words my fault. You are right that you can deduce the minimal fee, which is some cases is zero, by among others looking at the age of your inputs. Etotheipi started a thread on this here: https://bitcointalksearch.org/topic/transaction-fee-clarifications-51081
For now I have chosen a conservative approach where the fee is 0.0005 * (1+int(transactionSizeinBytes/1000)). I will be looking into optimizing this going forward.
The paramount thing to note here is that it is critical that the fee calculation is not too low, as you may risk the transaction is not propagated through the network or accepted by a miner. In scenarios where you manage your own block chain and end up with a transaction that got stuck you can basically delete the block chain, keep your wallet keys and load it anew, and finally make a new transaction with a larger fee. With the BCCAPI I cannot do this as I don't have a separate block chain per wallet, and don't want to spend the processing power to scan it anew whenever some poor guy sent out a transaction with a zero fee. In the end I would like this to be simple and safe to use.

No address book: This feature is an App feature and independent of the BCCAPI. It may be a good thing to add to the App going forward, but I guess that it depends on the use-case. If we want it to look like your ordinary wallet, then you do not have an address book or a transaction log for that matter. Whenever you pay you grab the money and pass it on to whoever you are trading with. However, the reason why I don't have an address book and transaction log for my ordinary wallet is that the first doesn't make sense and the latter is very cumbersome to manage. With a Bitcoin wallet this is both feasible and practically manageable. As for the transaction list the BCCAPI already has this functionality. It just needs to go into the App. I'll pass this onto the developer at Miracle and see what he thinks.

In the end the goal with the App is to be simple and easy for anyone to absorb, so maybe transaction logs and address books is something that could go into a Pro version?



 

Very nice!  What technology was used to create this?  Is it something very specific to Android or would it be easy to port to the iPhone (and run on a jailbroken iPhone)?

Trying it out at the moment - nice work!

A Bitcoin spinner?

Just tried it. This is a great piece of software.

Simple and effective. Nice work!

I got the bitcoin right away ("on its way" to me).  And it was confirmed as I was typing this post.

Update with full review

Compliments:  Very clean, minimalist, simple interface. Very, very fast: so much better than a BitcoinJ-based client (no offense to the creators of BitcoinJ as their efforts are incredible, but this uses mobile phone resources much more effectively).  I really like the QR code-based wallet export, too.

Negatives:  Forces a .0005BTC fee for sending a transaction rather than intelligently deciding whether it's possible to send the requested amount without a fee. No address book.  No way to connect to a different BCCAPI server in the app (if you want to run your own, I can see people using BitcoinJS and/or Electrum servers with a BCCAPI front-end in the future).

Differences that aren't necessarily negatives:  No transaction history, just a balance.  Single bitcoin address only.

All in all, it's very clean and beautiful and probably doesn't need anything more considering the primary use case (paying with/receiving bitcoins in person).  I really, really like it.  It acts like an actual cash wallet, not a bank account.  You know your balance and you pay to the address given to you by the recipient/shop in person.

We have a winner! 1 BTC on its way to you.

Please share your user experience.

Here's my photo.

2.2.x and forward cover roughly 85% of the devices out there. As far as I remember the developer mentioned that it wasn't tested on 2.1.x and earlier, which is why it wasn't marked as compatible with those devices. However, it still might work. I'll send him a note and let's see what can be done.

Explains it; my phone has 2.1.

Android version 2.2 should do it. Just follow the links in the post.

Looks nice!

Android market tells me it can't find it. I think it does that when a program is incompatible with the device. What are the requirements?

BitcoinSpinner uses the BCCAPI,  which connects to a server. The server  holds the block chain, and the public key of your Bitcoin address is uploaded to the server. This allows the server to scan the block chain for matching incoming transactions. The corresponding private key never leaves BitcoinSpinner. Whenever BitcoinSpinner needs to send Bitcoins it asks the server to give it an unsigned transaction comprising of unspent inputs, and outputs sent to the receiver + plus change sent back to yourself. BitcoinSpinner verifies that the transaction only sends to expected receivers, signs the transaction, and lets the server transmit the transaction to the Bitcoin network. More info on the BCCAPI and sources available here.