Dangerous Prototypes

Other projects => Past projects => Breakout boards => Topic started by: ian on December 15, 2010, 05:42:38 pm

Title: MMA7455L 3-axis accelerometer shipping
Post by: ian on December 15, 2010, 05:42:38 pm
We used the MMA7455L 3-axis accelerometer in the USB POV toy. It was a though chip to solder, so we made some breakout boards.

This is an inexpensive chip, only ~$2 in 1s. Our breakout board is $15, about $5 cheaper than SparkFun's cheapest accel breakout. We only had 20 made this time, all hand-soldered, but we'll make 100 in the next batch and maybe they'll be even cheaper.

Buy it here:
http://www.seeedstudio.com/depot/mma745 ... Path=61_68 (http://www.seeedstudio.com/depot/mma7455l-accelerometer-breakout-board-p-724.html?cPath=61_68)

Read about the design here:
http://dangerousprototypes.com/docs/MMA ... kout_board (http://dangerousprototypes.com/docs/MMA7455L_breakout_board)

Bus Pirate demo here:
http://dangerousprototypes.com/docs/Bus ... elerometer (http://dangerousprototypes.com/docs/Bus_Pirate:_MMA7455L_accelerometer)

Do you think breakout boards are a worthwhile addition to the Dangerous Prototypes collection?
Title: Re: MMA7455L 3-axis accelerometer shipping
Post by: Eric on December 15, 2010, 08:15:17 pm
[quote author="ian"]
Do you think breakout boards are a worthwhile addition to the Dangerous Prototypes collection?[/quote]

I don't have a need for this one but, in general I would say yes, definitely.

Break out boards are often the only things SparkFun has that I can't easily get somewhere else.

This means I often end up buying more than just the breakout boards from them since I am placing an order anyway.  Not that there is anything wrong with this or with SparkFun but, I think this same logic could help DP as well.  If someone places an order to get one item they want, there's a good chance they'll get something else while they're there.

While Seeed is much slower for me in the U.S. than SparkFun they are a little cheaper so when I'm not in a hurry they're fine.

-Eric
Title: Re: MMA7455L 3-axis accelerometer shipping
Post by: IPenguin on December 15, 2010, 09:43:03 pm
I think a good selection of affordable SPI/I²C sensor, ADC/DAC, memory, interface etc. breakout boards
is a must have for any business addressing makers, hackers and electronic hobbyists. Like Eric said,
many customers will buy them because they either need them to test an idea, for quick prototyping
or just out of curiosity. One way or the other they will complement the portofolio, attract attention and
generate more sales.

I would have to look into the orders of the last year or so but I think we spent more money on breakout
boards than on development and evaluation boards.

P.S. This first breakout board seems to miss the axis/orientation marking(s) every accelerometer (and gyro) breakout should have ;)
Title: Re: MMA7455L 3-axis accelerometer shipping
Post by: ian on December 15, 2010, 09:53:40 pm
The new version currently in production and the USB  pov toy will both have them.
Title: Re: MMA7455L 3-axis accelerometer shipping
Post by: Sjaak on December 16, 2010, 12:23:05 am
[quote author="IPenguin"]
I think a good selection of affordable SPI/I²C sensor, ADC/DAC, memory, interface etc. breakout boards
is a must have for any business addressing makers, hackers and electronic hobbyists. Like Eric said,
many customers will buy them because they either need them to test and idea, for quick prototyping
or just out of curiosity. One way or the other they will complement the portofolio, attract attention and
generate more sales.
[/quote]

I think breakout boards quickly help to develop a (final) product. It is a matter of combining some board together and viola!! Breakoutboards are the swiss army knives of electronic engineers..

BTW Have some patience :X
Title: Re: MMA7455L 3-axis accelerometer shipping
Post by: sqkybeaver on December 16, 2010, 01:11:58 am
i agree w/ sjaak, and it is a nice clean board too.
Title: Re: MMA7455L 3-axis accelerometer shipping
Post by: arhi on December 16, 2010, 03:04:21 am
/me likes breakout boards :)
Title: Re: MMA7455L 3-axis accelerometer shipping
Post by: arhi on December 16, 2010, 03:31:11 am
WOW, seeeeed now accepts ccard so no need to go trough nasty ppal any more :D yipiiiiii .... I ordered 2 of those breakout boards 10sec ago :D - I want to put them on the reprap head (I have head that goes in XY and bed that moves in Z.. this allows me fast XY movement but I want to measure g-force on the head when I change direction so I can modify acceleration scheme for the movement)

btw, a hint for a great breakout board .. accelerometer + gyro on the same board - especially if you use i2c or spi chips, they can share the bus (have separate cs for spi) and I found that doing anything "interesting" you need both accelerometer (what a word) and gyro in order to keep things "straight" :D (I still have not mastered the technique yet :( but .. reprap is keeping me occupied :D )

other idea for breakouts - sensors, different sensors .. maybe bunch of them packed on single board (temp+humidity+air-pressure+rtc+battery - for e.g. all on i2c bus :D )
Title: Re: MMA7455L 3-axis accelerometer shipping
Post by: ian on December 16, 2010, 08:03:23 am
That sounds like a great idea. Do you have a gyro in mind?

I've tried giant I2C demo boards in the past, but lots of chips seem to use the same I2C address.
Title: Re: MMA7455L 3-axis accelerometer shipping
Post by: arhi on December 16, 2010, 09:11:02 am
yes that tends to be an issue with i2c ... as for the gyro - I went trough the sparkfun's gyro buying guide (http://http://www.sparkfun.com/tutorials/167) few times and I'm still not sure ... I used accels so far and I kinda understand something about them and all I can say about gyro's is - I think with them my "standing robot" would work better and longer, but I have never tried.. and ordering bunch of different ones just to find out what to use ... donno, crossed my mind but ..

ITG-3200 - this looks like a good choice

btw, similar board from sparkfun: http://www.sparkfun.com/products/10121 (http://www.sparkfun.com/products/10121) ... I wanted to order it but I had some issues with sparkfun and local customs (trying to charge me customs fees 3x more then the value of equipment in shipment) ... no such problems with seeed :)

(I do have here LPR530AL and LPY5150AL breakout boards from sparkfun waiting to be unpacked - that I purchased as one is 300°/s and other is 1500°/s so I can test what that actually mean in real life but never got to it)
Title: Re: MMA7455L 3-axis accelerometer shipping
Post by: ian on December 16, 2010, 10:42:51 am
Wow that's an expensive board :)
Title: Re: MMA7455L 3-axis accelerometer shipping
Post by: sqkybeaver on December 16, 2010, 01:25:43 pm
gyros tend to be a little out of reach for shoestring budget projects, they have a 9DOF board that is ridiculous but all 3 chips share the same IIC bus. all of thoes QFN packages are hard to solder. silabs.com has a good tips and hints page for manually soldering them. as all but 2 of their micros don't have dip versions.
Title: Re: MMA7455L 3-axis accelerometer shipping
Post by: Sjaak on December 16, 2010, 04:21:06 pm
QFN is easy to do (if you know how) Before I had an hot air station, I used an old clothing iron, removed the thermostat, connect it to the mains. Then heat the PCB up (have the qfn area a bit tinned) and when the solder is melted put the qfn chip on the PCB, wait a bit an let it cool down (remove the pcb from the iron)

However I can imagine you dont want to have the risk of a multi-$$ chip being fried :)
Title: Re: MMA7455L 3-axis accelerometer shipping
Post by: sqkybeaver on December 16, 2010, 04:29:10 pm
i avoid hot air like the plague, unless the bottom pad is needed as heat sink. I use no clean flux on board and bottom of chip and with small tip roll over solder on about half of pins and push excess to other half of pins. stereo microscope is very helpful.
Title: Re: MMA7455L 3-axis accelerometer shipping
Post by: ian on December 16, 2010, 06:39:14 pm
Hot air is ok, you just gotta keep er moving. This part is lga and doesn't have any exposed pads to solder, how air was the only way to do it. First one was bad, the next three were fine.
Title: Re: MMA7455L 3-axis accelerometer shipping
Post by: sqkybeaver on December 16, 2010, 07:37:26 pm
for small projects i would stay away from bga lga and the likes.
Title: Re: MMA7455L 3-axis accelerometer shipping
Post by: tayken on December 16, 2010, 07:55:41 pm
For BGA, I would probably use the hot skillet method as I don't have a hot air station/gun. I didn't had the chance to try it out yet though...
Title: Re: MMA7455L 3-axis accelerometer shipping
Post by: arhi on December 16, 2010, 08:14:56 pm
[quote author="ian"]
Wow that's an expensive board :)
[/quote]

yes it is - and you can see how much are the chips themselves so - see where I'm coming from :) - you could probably make 5DOF, 6DOF and 9DOF boards much cheaper then those on sparkfun ..
Title: Re: MMA7455L 3-axis accelerometer shipping
Post by: ian on December 16, 2010, 08:48:00 pm
Is there an actual distributor.  I saw the itg chip quoted as 15 in 1s, but I can't actually find anywhere to get any.
Title: Re: MMA7455L 3-axis accelerometer shipping
Post by: arhi on December 16, 2010, 08:56:57 pm
I see it here http://invensense.com/mems/catalog.html (http://invensense.com/mems/catalog.html) for 10$ directly from manufacturer (also there are "distributor" links too) ..

on the other hand, check this one out: http://invensense.com/mems/gyro/mpu6000.html (http://invensense.com/mems/gyro/mpu6000.html) - would be cool for making break board ... just I don't c a price anywhere ... http://www.cdiweb.com/FeaturedProducts. ... &NavType=1 (http://www.cdiweb.com/FeaturedProducts.aspx?type=709&manf=383&NavType=1) .. maybe it would be cool to ask them for quote
Title: Re: MMA7455L 3-axis accelerometer shipping
Post by: arhi on December 16, 2010, 09:01:28 pm
btw - don't get me wrong I have NONE WHAT SO EVER EXPERIENCE with these chips! They just look "best" from the quick look on what sparkfun is offering... I never seen any of them work. I only used ADXL330 on the mikroE break out board (http://http://www.mikroe.com/eng/products/view/133/three-axis-accelerometer-board/) (analog), and I ordered some analog gyro's .. so not only that I have not used chips I "recommend", I never used i2c/spi accelerometer nor i2c/spi gyro (I will soon receive MMA7455L from seeed so I will have a chance to ..)
Title: Re: MMA7455L 3-axis accelerometer shipping
Post by: ian on December 16, 2010, 09:24:59 pm
No worries, I'm just happy to check out a new chip
Title: Re: MMA7455L 3-axis accelerometer shipping
Post by: arhi on December 16, 2010, 10:10:18 pm
just wanted to be sure I was not saying "I tried them and they are cool" :D ... for some reason I started with analog ones - no idea why... but I think digital are much easier to work with
Title: Re: MMA7455L 3-axis accelerometer shipping
Post by: rsdio on December 17, 2010, 12:57:17 pm
[quote author="ian"]
Wow that's an expensive board :)[/quote]No kidding!  For that price, they should include a small USB PIC and USB mini port, and provide a whole programmable system for the same $65.