Can a Basic stamp do this job?

ken lilja

I am looking to find out if this is something that a BSII can do.
I want to read voltage, current and temperature sensors and display the readings on a display, minimum 12 characters (preferably one with a decent "V") One sensor has a built in ADC with a 2 wire output. The other 2 sensors will need a 12 bit, preferably a 3.3V reference voltage ADC. Possible sensors: http://www.sparkfun.com/products/10644 http://www.sparkfun.com/products/9418 or http://www.parallax.com/Store/Sensors/TemperatureHumidity/tabid/174/CategoryID/49/List/0/SortField/0/Level/a/ProductID/84/Default.aspx
I do have a BSII.

Possible operational schemes depending on what the processor can do:
A) 1 reading, reading changes to the next sensor every 4 seconds or so.
1 reading, selected manually with a switch.
C) 1 reading, reading changes to the next sensor every 4 seconds or so, or selected manually with a switch.
D) 3 readings on a multi line display.
1) as D) above with a clock or varying irreverent statements on a 4th line.
Refresh rate at least 2 Hz.
If doable, is there a "best" version of the BSII for this task?
I have almost no experience with programming, some electronics background. This is a project to support my main hobby of radio control, so the "less" I have to learn the better. I do have several books and a BOE for the BSII, (I did complete a project where the BSII managed some relays based on push button inputs, current state and time delays).
If I know that this is within the capabilities of the BSII series then the searching and battle begins!
Thanks for you time and opinions,
Ken Lilja

Mike Green

The BS2 does not have built-in I2C (usual 2-wire protocol) statements, but there are subroutines that will do this for you described in a Nuts and Volts Column you can download (#85?). There are other 12-bit ADCs that Parallax carries and there's sample code for handling them. They come in 2,4, and 8 channel versions. If you get a 4 line x 20 character display with a serial interface (like the one Parallax carries) you should be able to read all the sensors and display the results pretty much as fast as you like, well under 1/4 second, limited more by display speed than anything else.

A BS2 will do for this, but the BS2p or BS2pe or BS2px has built-in I2C statements and more memory that I'd prefer to have if I didn't already have a BS2.

ken lilja

Mike,
Thanks for the response. A couple more questions.
The BS2p has built in I2C support. Can I find a 12 bit ADC that uses this protocol?
I also see that the BS2p has a built in lcd controller. It seems to be limited to 2x24 and 4x12. I haven't found any 4x12 displays. Can I use a 4x16 or 4x20 display with a serial different controller?
Thanks for any info.
Ken Lilja

Mike Green

There are two different kinds of LCD controllers for this sort of use, serial and parallel. Serial controllers usually only need one or two I/O pins while parallel controllers need 6 or 10 or more I/O pins. The LCD statements in PBasic work with parallel controllers. You'd use the SEROUT statement with a serial controller.

There are I2C ADCs including 12 bit ones. I don't have any specific recommendations. Maybe someone else can chime in with one.

Tracy Allen

There are plenty of 12 bit and higher ADCs that use I2C protocol, but the ones I think of are surface mount parts. Are you comfortable with that?

One I've used with the Stamp (have code for!) is the MAX11612 and the firmware-compatible MAX1236. It is a 4-channel (2-channel differential) device with an included 4.096V reference, in a 8-pin uMax package. Other ADCs in the same family have up to 12 inputs, or a 2.048V reference for use say with the Propeller.

ken lilja

I bought a BS2px. It was cheap at $63.20 at Robotshop. I also picked up the Parallax 4X20 LCD display and a couple of DS1620 temp sensors.
Tracy, I went with a MAX11615 ADC. Being of the same family as the MAX 11612 I hope that it can use the same code. Could you send me a copy?
Thanks for the help!
Ken