Difference between revisions of "Water control project"
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====basic control==== | ====basic control==== | ||
http://sitebuilt.net/images/IMG_1074.JPG | http://sitebuilt.net/images/IMG_1074.JPG | ||
:comparators - LM324N quad op amp | |||
:flip flop - 74HC74AP dual D flip flop | |||
FUNCTION TABLES</DIV><DIV style="top:233;left:75" class="b ft22">Table 1</DIV><DIV style="top:233;left:137" class="b ft24">See note 1</DIV><DIV style="top:394;left:75" class="b ft22">Table 2</DIV><DIV style="top:394;left:137" class="b ft24">See note 1</DIV><DIV style="top:525;left:75" class="b ft2">Note</DIV><DIV style="top:548;left:75" class="b ft29">1. H = HIGH voltage level;</DIV><DIV style="top:571;left:100" class="b ft33">L = LOW voltage level;</DIV><DIV style="top:594;left:100" class="b ft36">X = don’t care;</DIV><DIV style="top:613;left:100" class="b ft40">↑ = LOW-to-HIGH CP transition;</DIV><DIV style="top:640;left:100" class="b ft48">Qn+1 = state after the next LOW-to-HIGH CP transition.</DIV> | |||
The water level sensors are just thermostat wire. When immersed the resistance decreases to about 50K. Each sensor goes to a comparator. The low level comparator goes HI when out of water and the high water sensor goes HI when immersed. The output of the low level comparator goes to the D input and the output of the high level comparator drives the clock. When the D flip flop output Q is HI the pump goes on. | The water level sensors are just thermostat wire. When immersed the resistance decreases to about 50K. Each sensor goes to a comparator. The low level comparator goes HI when out of water and the high water sensor goes HI when immersed. The output of the low level comparator goes to the D input and the output of the high level comparator drives the clock. When the D flip flop output Q is HI the pump goes on. | ||
Revision as of 23:38, 7 January 2013
back to electronics
water control project
Automatically control the level of the pond by using a lawn sprinkler relay to inject water into the pond when it falls below a critical level. Water gets added while the pumps are on until it reaches the max level then it goes off. If you turn on the pumps again it doesn't continue filling but waits to inject water til the water falls to the low water sensor.
basic control
- comparators - LM324N quad op amp
- flip flop - 74HC74AP dual D flip flop
FUNCTION TABLES
The water level sensors are just thermostat wire. When immersed the resistance decreases to about 50K. Each sensor goes to a comparator. The low level comparator goes HI when out of water and the high water sensor goes HI when immersed. The output of the low level comparator goes to the D input and the output of the high level comparator drives the clock. When the D flip flop output Q is HI the pump goes on.
When the water rises sufficiently so the high sensor is immersed, it goes HI sends a rising pulse to the clock which puts what's on the D input on the Q output. In this case that is a LO since the lower sensor is immersed. So the output goes LO and the pump goes off.
When the water falls below the high limit sensor the pump stays off since when the high limit opens it sends the clock LO on a falling pulse which does not change Q. So the pump stays off until it falls past the lower sensor.
todo
Pick up my phone, go to a web site, have there be a series of buttons on, off, 10, 20, 30, 60.
The buttons could be from a client side jquery-mobile page. Timing would seem suited to the server. Server would send an on message and start a timer. After the time elapsed it would send an off message. Client would poll server to see what the status is and the time remaining.
version 1
Basic control is working in an outdoor circuit box mounted on the bridge next to the lawn sprinkler relay.
version 2
Click the button pump goes on in pond.
- send '1' to arduino, to tun on relay
- send '0' to arduino to turn off device
