BitcoinSpinner was originally announced on the main board, and it is time for it to have a life in the Alternative Clients section. A Danish software company Miracle A/S has implemented an awesome Bitcoin client for Android called BitcoinSpinner. The developer is not active on this forum, and since it is built on top of the BCCAPI, and I have participated with testing and suggestions I am proud to announce it here. BitcoinSpinner is minimalistic, to the point, and is intended for broad adoption. Features: - Ready for use right after installation - The block chain is managed by a server.
- NOT a Bitcoin bank - All private keys are kept in app-private storage on your device.
- Send & Receive Bitcoins using QR codes.
- Share your Bitcoin address using Gmail, Twitter and more.
- Backup & Restore your wallet using QR codes.
- It is Open source - Geeks can download the code, review it, and roll their own.
Because BitcoinSpinner does not download and manage the Bitcoin block chain it is ready for use immediately. This also means that it has: - Low storage requirements.
- Low bandwidth requirements.
- Low CPU requirements.
- Low battery consumption.
BitcoinSpinner comes in two versions and is available on the Android Marketplace: Note that this is a beta release. Use with caution.You cannot have an announcement like this without a bounty: The first one to post a picture in this thread of their Android device with a scannable QR address code displayed with BitcoinSpinner will get a shiny new Bitcoin. Your feedback is appreciated! The feedback has been impressive, and in the mean time forum members have provided a French and Swedish translation. To get the new version just go ahead and update BitcoinSpinner on the Android Market. While you are there please give BitcoinSpinner a rating! We should have BitcoinSpinner in all major languages, so if you are up to it then please go to the Google Code page and contact the developers. |
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The problem is you still have to wait to check if the transaction actually took place.
I am not sure what problem you are referring to. Please elaborate. |
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Hello, I'm working on another alternative client Electrum, which has basically same goals like your implementation, but for desktop client (at this moment). I like your job, except this: Simply put the BCCAPI (Bit Coin Client API) allows you to create a light-weight secure Bitcoin client in Java.
Is there any reason why to use some Java-specific protocol? I'm solving "ideal way how to do universal network layer" right now and thinking about some universal "Bitcoin client API" too, but I prefer platform independent protocol. I didn't found any format specification on BCCAPI (is there any?) and I'm too lazy to read Java sources (because I'm not a Java developer), but do you think there's some room for cooperation on making this protocol more universal, not Java-oriented? Interesting. Java is a programming language, not a protocol. The wire protocol is REST-like HTTP(S), and nothing prevents you from calling the server side from python. The raw API has 7 functions and is well documented with the Java interface declaration: http://code.google.com/p/bccapi/source/browse/trunk/src/com/bccapi/api/BitcoinClientAPI.javaThe implementation of the interface is 200 lines of easy-to-read Java code and available here: http://code.google.com/p/bccapi/source/browse/trunk/src/com/bccapi/core/BitcoinClientApiImpl.javaApart from this there is a bunch of Java classes for transactions and utilities that make it really easy to implement a UI on top of it. |
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Thank you community for all the support. Help pushing this app forward by - Rating it on the Android Market. A rating is good, some words even better.
- Offering translations to other languages, by going to http://code.google.com/p/bitcoinspinner/ and contacting the authors. I just heard from Mats Henricson, who offered to make a Swedish transaltion.
- Help us getting even better usability by suggesting feature improvements, a better color schemes, nicer icons, or even coin-sounds when Bitcoins tick in.
- Check out the code and submit patches
I just tried this app, and so far, it's awesome! Just what was needed. (Although the color scheme and/or UI look is not my favorite.)
Thanks. One way of improving this could be to grab the screenshots, fix them up to your liking in photoshop, and send them to the authors. I'm testing BitcoinSpinner right now. If I understand correctly, when I want to backup the wallet I need to export the QR code and keep it in a safe place because it contains my private keys unencrypted.
I would like to know if it's possible to generate the wallet from a seed like you do in the SimpleClient that comes with BCCAPI. I really likes this feature because there is no need to backup the wallet, you just need to remember the passphrase.
BCCAPI is amazing. Keep the good work!
Thanks. BitcoinSpinner generates the random seed when it is first started, so it doesn't use the "generate seed from passphrase" feature which is available in the BCCAPI. The backup QR code contains the seed that the private key is generated from, so yes, you should print it out on paper and keep in a safe location. A forum member is working on a different android client based on the BCCAPI where you use a passphrase + salt for generating the seed, just like the SimpleClient. However I am not sure how close this client is for a beta release. Since he is a member of this forum I'll let him decide when he is ready to announce it. |
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...
This makes sense and I'm glad that you're going the conservative route instead of just letting the user specify a 0 fee. By the way, looking through the code for the BCCAPI, it looks like it's pretty easy to just instantiate it and point it to another server, which means someone with an Electrum or NodeJS server could fairly easily set up a BCCAPI-compatible web API as well and run a service which competes with yours. This is probably a good thing, though this particular app doesn't let you choose the URL(s) to which it connects.
Competition is a good thing. So far everything is provided for absolutely free, and that is hard to compete with  Going forward I am hoping that this service can continue to run on donations. The total donation income for the BCCAPI is roughly a stunning 2 BTC, and my expenses for the servers at Rackspace alone are 50$ a month. ...
By the way, I did a little bit of research on MIracle and it looks like they have a brewery, too! I'm going to see what I can do about getting my hands on some of their beers.
Yummy. Maybe they accept Bitcoin  |
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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)?
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. 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. 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 |
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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)?
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. |
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I got the bitcoin right away ("on its way" to me). And it was confirmed as I was typing this post. Update with full reviewCompliments: 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. 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://bitcointalk.org/index.php?topic=51081.0For 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? |
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Here's my photo.
We have a winner! 1 BTC on its way to you. Please share your user experience. |
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Android version 2.2 should do it. Just follow the links in the post.
Explains it; my phone has 2.1. 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. |
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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?
Android version 2.2 should do it. Just follow the links in the post. |
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if it does not download and manage the Bitcoin block chain.
how do you get confirmations?
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. |
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A Danish software company Miracle A/S has implemented an awesome Bitcoin client for Android called BitcoinSpinner. The developer is not active on this forum, and since it is built on top of the BCCAPI, and I have participated with testing and suggestions I am proud to announce it here. BitcoinSpinner is minimalistic, to the point, and is intended for broad adoption. Features: - Ready for use right after installation - The block chain is managed by a server.
- NOT a Bitcoin bank - All private keys are kept in app-private storage on your device.
- Send & Receive Bitcoins using QR codes.
- Share your Bitcoin address using Gmail, Twitter and more.
- Backup & Restore your wallet using QR codes.
- It is Open source - Geeks can download the code, review it, and roll their own.
Because BitcoinSpinner does not download and manage the Bitcoin block chain it is ready for use immediately. This also means that it has: - Low storage requirements.
- Low bandwidth requirements.
- Low CPU requirements.
- Low battery consumption.
BitcoinSpinner comes in two versions and is available on the Android Marketplace: Note that this is a beta release. Use with caution.You cannot have an announcement like this without a bounty: The first one to post a picture in this thread of their Android device with a scannable QR address code displayed with BitcoinSpinner will get a shiny new Bitcoin. Your feedback is appreciated! |
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@gmaxwell, just about what I wanted to say. Thanks.
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You're close: it is: int64 nMinFee = (1 + (int64)nBytes / 1000) * nBaseFee; You are also close, it is more like int64 nMinFee = (1 + (int64)nBytes / 1024) * nBaseFee; Which is like roundUp(txSizeInKb), using nBaseFee==MIN_TX_FEE(==0.0005). However, if I understand correctly, that is the min fee for Satoshi-based miners to accept your tx to be included in a block. You only need nBaseFee==MIN_RELAY_TX_FEE (==0.0001) to get the tx propagated through the network: and that should be enough for it to find its way to a miner that will accept sub-standard transaction fees. Depending on what proportion of miners accept this fee, it could take a few blocks to get into the blockchain. If you make 0.0005 the base fee, then all miners should try to include your tx in the next block.
Also, if you have any outputs that are strictly less than 0.01, you will need to include that MIN_TX_FEE or MIN_RELAY_TX_FEE regardless of tx size. Similarly, if the size is small but not sub-cent outputs, you will still pay a fee for low-prioirty transactions (summing to less than 1-BTC-1-day old).
OK, but this will also be covered by the above formula. |
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Well then, that answers my question -- these tx fee rules need to be followed, unless you plan to seek out specific miners who will accept these transactions. For a regular client, there's no guarantees you will be connected to a node that accepts them, and thus the user will be very confused when their tx says "Sent!" but then an hour later nothing has happened.
If I am not in a position to calculate whether the a transaction could be in fact free, and I want to be 100% sure that it went through, would this be a simple/safe rule to follow? fee = 0.0005 BTC * min(1, kbSizeRoundDown(tx)) |
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Bitcoins are not encrypted. Bitcoin does not use encryption at all. Cryptography yes, encryption no. |
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