Help, help!
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I've built the homebrew make-your-own-comparator-board version of the Yuriy's bluetooth TouchDRO.
http://www.yuriystoys.com/p/android-dro.htmland
http://www.yuriystoys.com/p/msp430-launchpad-mixed-scale-dro.htmlHoping to use a combination of digital calipers and an "Igaging" type scale I had on hand.
Everything went well (except for what I don't realize didn't) during construction -- had a blast making the stripboard circuit using a drill bit -- cool process! BUT.......... It didn't actually work with either my scale, or my calipers.
So to troubleshoot, I removed the homemade board and reprogrammed the TI board for "Basic Igaging" operation. Then my scale worked fine. Switching back to the "Mixed scale" version and attaching the board repeated the problem. They say doing the same exact thing twice and expecting a different result is a sign of insanity. Well I've done this at least ten times, so draw your own conclusions!
To me, the problem can only be in my homemade board, then, or a difference in the firmware, or since different pins on the TI board are used as clock and data connections (for Basic vs Mixed operation), maybe the TI board is partially damaged or defective. Problem is......I have no idea which is at fault. Or where to start.
Unfortunately there are no schematics available. And no clear list of what igaging scales might work with the Basic version and NOT with the Mixed scale version of the firmware. And no self test program for the TI board in hex or txt format that I can load to see if the input pins P2.0-P2.2 are functioning.
Okay I'm going to stop explaining and list what I know here. Any help would be GREATLY appreciated:
Details:
Voltage Shifter Board: I did the bare strip board build.
Scales: I have an aluminum Digi-mag Igaging type Shahe scale, and a couple of Chinese calipers
TI board: EXP430G2 w/ M430G2553 chip
Programmer: FET-Pro-430 Software Pkg. - LITE
Firmware: DigitalReadout_Universal_V1.0.hex,
Symptoms:
If I flash the TI board for Digital Readout Basic Igaging support firmware - (without using the voltage shifter board) and connect the Shahe scale clock line to P 1.7 and the data line to any of 2.3,2.4, 2.5 the bluetooth tablet reads each perfectly.
If I flash the TI board for Digital Readout Universal, and connect the voltage shifter board with the same Shahe scale (data line to P2.5 and clock line to P2.0), nothing changes on the bluetooth tablet when I move the scale.
If I connect a caliper (clock to P2.1, and data line to p 2.4), the same thing happens. No change on the Bluetooth tablet when moved. (However, the caliper's own readout shows correct measurement moves, and that it is properly powered.)
Checked so far:
1.) All wiring has been checked several times. But we know this is probably the fault, anyway....right?
2.) Voltage to both scales was checked while connected. Shahe is getting 3.5V and caliper is getting 1.5V. This was checked to their individual grounds. Caliper is powered up and shows readings
3.) LM339 pin 3 =3.5v measured against pin 12 (ground). Check.
4.) LM339 pin 6 = 1.7v measured against ground. should be half Vcc. Check.
5.) I replaced the upper LM339. No difference
6.) I have a second identical TI EXP430G2 board. I've substituted that in, and get exactly the same results as the first board. But maybe I wrecked the inputs on both?
7.) Running Android BlueTerm app shows good connection and continuous output of x0,y0,z0,w0 to the tablet. Moving the scales makes no change.
I have tried the 1.0 version of the firmware, as well as the 0.3 version. And also both the .txt, and .hex versions.
I can return to Basic igaging mode firmware and the Shahe scale again works fine. Can't test the calipers in this mode. However their readouts still work fine.
Any suggestions? This is really driving me nuts.