MAKE your own controller

[kwirky]

Originally Posted by Static

http://www.parallax.com/

I played with The basic stamps for a while. I could make buttons flash LED's and stuff, but the hard part came when I had to try selecting transistors and relays to turn the 5v at low current into something useable.

It looks like that make controller actually ouputs a bit more current,and might be more useable. Maybe even just to log temperatures and stuff on your computer. How would you go about making it switch a relay to turn a heater on/off?

If you go anywhere with this project please post cause I'd really like to learn how you do this

supposedly it outputs whatever current your power supply gives. they say to select a power supply that matches the current of the electronics you're running. If it wouldn't supply enough power for the relay, I would run a jk flip flop to provide the amperage required by the relay.

the thing's $150 US, and not in the budget until next paycheque probably, plus all the little tidbit electronics i'd end up purchasing to utilize it.

Anyone know how the probes of ph controllers and such work? i'm thinking they're a type of resistor, and the ph/ozone/whatever controllers just translate that resistance into a reading. think that's the case?

[midgetwaiter]

Seems like overkill to me, all you really need is a run of the mill PLC. That thing has capabilities you'd never need.

[mark]

Static: I'm using a PLC like device to drive SSRelays like here, simple and clean to switch heaters.

Kwirky: Queried American Marine about the output of their probe

e-mail reply AMI
"After proper calibration the probe will generate 59 mV per each unit of positive pH and the opposite will be negative mV. Example pH 7.0= 0 mV; a ph of 8.0=59mV a pH of 6.5= -30mV Good Luck...Lou Dell/AMI"

[kwirky]

Originally Posted by mark

Static: I'm using a PLC like device to drive SSRelays like here, simple and clean to switch heaters.

Kwirky: Queried American Marine about the output of their probe

e-mail reply AMI
"After proper calibration the probe will generate 59 mV per each unit of positive pH and the opposite will be negative mV. Example pH 7.0= 0 mV; a ph of 8.0=59mV a pH of 6.5= -30mV Good Luck...Lou Dell/AMI"

sweet thanks for getting me the info

I've considered simpler PLC's but this board gives the ability to program in C, instead of assembly. I would personally have more applications than just my own tank, and would buy one mainly for experiments and class work.