SparkFun Forums

[Maxwellfire]

First, i'm going to appologize for putting this in this forum, since it is not a sparkfun product, but I don't know where else to ask it.
I just bought the 10dof board from http://www.goodluckbuy.com/10dof-nine-a ... ensor.html. This breakout board appears to have pins that are not described in the datasheet, and not have ones that are described in the datasheet. The pins i'm unsure about are, CLO, CLI, DRY, FYN, ADO, and VLG. I think i can safely assume DRY is the same as DRDY on the datasheet. FYN might be the same as FSYNC, and VLG might be the same as VLOGIC. That still leaves CLO, CLI, and ADO. For my project, i need to be able to tell when each of the sensors has new data. The HMC5883L has the DRDY pin. The MPU6050 has the INT pin (I think. Correct me if i'm wrong). The BMP086 has the EOC pin. Unfortunatedly, i don't know if EOC is broken out. Another problem is with the ASDA and ASCL pins. These pins enable the user to get 9-axis MotionFusion data from the MPU6050 if they are conected to a 3-axis magnetometer. Part of the reason I bought the board is that it has the 3-axis magnetometer on it. Unfortunatly i don't think the SDA and SCL pins on the magnetometer are connected to ASCL and ASDA. Instead, I think they are just connected to the SCL and SDA on the breakout. To make matters worse, when I contacted the company asking for a schematic of the breakout board, they never replied. Could somebody please advise me on what to do.

[Duane Degn]

Can you find the datasheet for each component on the board? If you can, then you could check (with a multimeter) which pinout connects with which pin on the chips and use the datasheet to figure out the pin's purpose.

[alex.forencich]

If you can't get a schematic, you'll have to reverse engineer it. It looks like a very simple board, though. All you really need are the datasheets for the chips, some scratch paper, a pencil, and a multimeter. And maybe a magnifying glass. Google is your friend for the datasheets. Follow the traces either visually or with the continuity checker and draw out the circuit as you go. I'm sure you'll be able to puzzle out most of the schematic long before they get back to your email.

[Maxwellfire]

Yes. When I was writing my original post, i was looking at the datasheets for the different chips to make sure i wasn't saying something that was blatently inccorect. I have the data sheet for all three. I first have to wait for the board to get here from china. The reason I was posting is that i'm making the second version of a custom pcb from batchpcb, and i wanted to have the board finished by the time the breakout came. I guess i'll just wait for it to come. Thank you 2 guys for helping me.

[Maxwellfire]

One last question, has anyone had any luck with cutting traces on a circut board. Because if ASCL and ASDA arn't conntected, i might be able to solder a couples wires to the magnetometer.

[alex.forencich]

A nice sharp utility knife works quite nicely. You need something with a sharp point, so if the point is dull, get a new blade. Don't cut straight down, instead make two cuts at opposing angles on the same spot to form a V shaped groove. This ensures the trace does not re-connect. Be cafeful, though! FR4 is pretty tough. I would practice on a junk board before going to town on the real thing. You really don't want to slip and cut yourself, other traces, or knock parts off.

[Maxwellfire]

I'll try that on one of the broken boards i have. One other question, how would i attach a wire to the now cut copper trace. should i solder it the pad that the chip is on? is it possible to scratch away the plastic on the trace and solder to the copper? what works the best?
ps: sorry to be asking so many questions, but i'm pretty new to PCB's.

[waltr]

The pad/pin of a chip can be easier but I have also soldered to a PCB trace after scratching off the solder mask with an Xacto knife.
Which you use will depend on a number of factors which include:
Width of trace. very thin traces are harder to solder to and tend to be mechanically weak.
Size and pitch of the chip. Very fine pitch chips are easy to get short bridges (shorts) across pins.
Where the trace is cut compared to where to chip is located.

[Duane Degn]

I usually like to solder to a trace rather than the pins of an IC if the IC has fine pitched leads.

Just scrap the solder resist off the trace you want to solder to. It's a good idea to use some flux in cases like this.

I agree with Alex's and waltr's advice about cutting traces and soldering. A single cut through a trace often isn't enough to break the connection.

I've heard there are special tools for cutting traces. I've always used and Xacto knife myself.