Field calibration problem

Larry C.

I have a propeller project nearly completed and I now have the problem of taking it out of the workshop and into the field. I need some means of reading a few sensor outputs and programming some calibration constants. No mains power is available. I guess I could invest in a tablet to do this, (assuming I could run the Prop IDE and a terminal program on it), but does anyone have any better (cheaper!) approach to this?

Thanks for any help.

T Chap

What type of sensors? Can the Prop have it's own sensors connected that are being monitored in your program, so you can have built in calibration?

Duane Degn

There are lots of small displays available and there are lots of ways to add a battery to a project.

I like these OLED displays from ITead Studio. They're only $5.

I used one in my aluminum wallet project.

The OLED displays need to be controlled by i2C or SPI but there are lots of displays with a serial interface. Parallax sells several LCD screens with a serial interface.

You could also use a NTSC monitor or a VGTA monitor.

idbruce

Larry

This may not be the most economical in long run or even the short run for that matter, it is just a suggestion, which depends on how close the remote location is to your shop.

Scenario 1: Go to the remote location and take your initial readings, then run back to the shop and rewrite your program with the new constants. Then go back to the remote location and upload the new program with a field programmer. Such as the one suggested here: http://forums.parallax.com/showthread.php/143892-Great-Weekend-Project-For-The-Propeller-DIP-Plus-Kit Note: The schematics have not been tested on a working board, however, I have a previous field programmer that I built that works just fine.

Scenario 2: You could possibly modify the project suggested above to enable on the spot programming.

Larry C.

TO: Duane and idbruce

Combining your two suggestions should give me just what I want.

Thanks to you both,

Larry

Cluso99

Can you store the constants in upper eeprom?
ie Do you have to reprogram your prop.?

I presume you will have P30 and P31 available?
With 2 pins free, you can add a ps2 keyboard and composite video with a few resistors.
See my 1 pin tv and keyboard objects in the tools section of the obex. A small car reversing monitor is ~$25 on ebay.

The idea is you make your program capable of a programming mode to change values.

Peter Jakacki

Larry, I do this all the time and it's very simple for me as I can communicate directly with Tachyon Forth over a serial link, be it USB or Bluetooth, and I do this via my smartphone or tablet or laptop, whichever. Typically I use Blueterm on my smartphone for something really on-the-spot and portable and connect to the device and I can check and change variables and constants or even the program. In fact I might even add an extra reporting functions on the spot as I interact with the Forth system and lock it into EEPROM.

BTW, I don't have to preprogram this "calibration" access in, every aspect of the code and data are at my fingertips, it's all part of running an interactive Forth environment on the Prop itself.

prof_braino

Peter beat me to it. I use propforth, and a HC05 bluetooth wireless serial cable replacement, and talk to a terminal proram on my android phone or tablet. Using forth to read and record the sensors is very handy.