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1  Using Arduino / Programming Questions / Re: How to read/write binary data from a file on an SD card on: September 10, 2012, 04:34:47 pm
Thanks very much to the commenters for your help.
I've gotten the binary reading to work.
As it turns out -- and often does -- this trivial little detail was one of the most time consuming parts of the whole project.  Considerably more so than writing the code.

Thanks again.
2  Using Arduino / Programming Questions / Re: How to read/write binary data from a file on an SD card on: September 10, 2012, 10:07:27 am
ardnut: can you let me know the name of the library and function for the speed test you're referring to?  I've already tried to go through all of the SD-related functions that I could find to find a binary read example, and I didn't find it.

3  Using Arduino / Programming Questions / Re: How to read/write binary data from a file on an SD card on: September 10, 2012, 10:03:38 am
PaulS: Can you provide 'trivial' code that does the "Read and store the most significant byte. Read and store the least significant byte. Shift the MSB 8 places left and add the LSB."

As to 'triviality', you may or may not be aware that on different platforms there are enough different ways of data being stored (eg which byte is LSB) that it can be pretty time consuming to try to work out, especially if you have several different data types to deal with.  I guess I was presuming that the libraries had a function to handle this, and it wouldn't be necessary to write one.


4  Using Arduino / Programming Questions / How to read/write binary data from a file on an SD card on: September 10, 2012, 12:56:18 am
I have not been able to successfully figure out how to read binary data from a file on an SD card.  I've tried the SDFat library and the arduino 'built in' SD functions.  I imagine that both are capable of this simple task, but I haven't been able to find how.  There are plenty of examples for how to read and write ascii characters, which is easy enough from the examples available, but I haven't found one for how to read (for example) two byte signed integer data from a file on an SD card.  I did find some posts of other people also having trouble with this, so I hope that this will be useful to the community at large.  Once I figure out how to read a single integer, I'm going to read both raw data from a headerless binary file, and the data section of a .wav file to create audio output directly on the arduino, without the wave shield.  Any help on the latter also gratefully appreciated.

Thanks for your help
5  General Category / General Discussion / Manufacturing Path/Estimating Production Costs for Arduino-Based Project on: September 08, 2012, 12:05:58 pm
I'd like to ask the community's help in thinking through the production path for an Arduino-based project.
Thank you for your time, which I hope will be useful to the whole community.  I hope that replies to this post will be useful to others in thinking through their final production path for Arduino-Based projects, as our project is pretty simple and uses relatively common components.
If things go well, we are working toward building a low-cost consumer product at meaningful scale (at least 10k unit production lots for initial small run, hopefully 100k unit lots for full production runs if things go really well).  The ultimate retail cost will need to be in the range of $50-150 -- still a wide range at this point because we are still working on pricing vs. features, largely based on the answer to this question.  Beyond the electronics costs that we are asking about here, the product will also need to include about $5-10 in non-electronics parts + assembly.
Before we go further in our development, we want to have a better understanding of the path towards production, and at least very rough estimates of final electronics production costs, so that we can make whatever early choices are going to be appropriate for later commercialization.

Question 1: Estimated production cost
What is a reasonable range of cost to estimate for final production for the electronics components of our microcontroller-based project?  If you have prior examples that you are familiar with, that would be great.  Also, if you (or someone you can recommend) might be interested in paid consulting, that would be greatly appreciated.  If we get a list of available potential consultants on this forum, I suspect that others might be interested as well.

Question 2: Component selection
What current prototype-level components will we probably want to remove, and what components might we ultimately choose?  What form/manufacturing method will the final product likely take?  If I can ask your indulgence, please give us the full names of components you suggest so that we can Google them, as we may not know what you mean if you use abbreviated names/numbers for chips etc., even those that may be familiar to others on this forum.

The prototype is a handheld, powerful, motor-driven device that can produce complex programmed sequences of movement, stored in memory, with additional motor sequences downloadable.
Here are the components that we are currently using in the prototype:
Arduino Uno
Motor controller shield
3A motor at 100:1 gearing
7.2V battery pack
Wall charger
Memory (need about .25Gig, currently using SD memory/SD shield)

Thanks very much for your help  smiley

6  Community / Gigs and Collaborations / Gig - Would Like to Hire Arduino Programmer for Audio Motor Controller on: September 07, 2012, 12:30:32 pm
Goal: Write code that allows audio output (eg from an ipod/MP3 player) to control the rotation direction and speed of a motor.
We would like to hire an Arduino programmer for the creation of a project that will convert audio input into the speed of rotation of a motor.  This would allow us to create arbitrarily long and complex motor programs, store them as audio files, and 'play' them out from an audio player, through the arduino to control a motor. This project is a prototype that we plan to build at scale later.  We are on a short timeline (ideally completed in the next few days or even sooner) to get an initial version built, so it would be really great if we find someone who is available and could start right away.  The basic coding is fairly simple, and there may already be code existing that performs a similar function.
I have attached a project specification as a Word file.  This described delivery of the hardware.  We would also consider bids for the coding only if you can test on your end.
We would like to ask interested developers to provide a project bid.  We envision this to be a <$500 project, taking less than a day to complete, but happy to hear your thoughts.
Thank you for your help.


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