I am wanting to build a circuit which controls a solenoid on/off to feed some cows.
I was wondering if anyone here could offer me some solutions? (12vdc)
The circuit should power a relay on/off, the pulse duration should be adjustable between 1-10 seconds.
The output pulses should be adjustable by a binary? switch located on the unit to control the number of pulses out of the circuit - i.e. a 16 position switch, when set at 1, one pulse on/off is generated, or when set on 16, sixteen pulses on/off are generated.
The unit once completed its output count should reset ready for the next cow.
The circuit should be controlled by a momentary push button.
Any help anyone could offer would be greatly appreaciated - I was orignally thinking of using a 555 timer to give me my output pulse, but then couldnt work out how to control it to preset values.
You can use a 555 to generate a pulse of 1-10 secs duration, but for generating a sequence of such pulses you will need additional ICs, including a counter. What is the interval between pulses?
Thank you both for your replies - I am new to circuits - but have been in the electricity business for 15+ years, and wanted to try and undertand a few more things but got totally stuck on how to do this!
I'd worked out how to get my pulse from a 555 but then couldnt undertsand how to A) start it with a pulsed input and B) limit the number of output pulses.
I was thinking of a binary switch with 16 positions - one being zero, the other being the number of pulsed on operations, similar to the type shown herehttp://elma.com/Americas/English/Products/RotarySwitches_4/CodedSwitches_47.aspx
The relay would be a 12dv coil, with a contact rating of 240v No greater than 3 Amps
I want it to (once the button has been pressed) energise for 6 seconds (relay on) then de-energise for 6 seconds, then depending on how many ON pulses I want continue until the preset figure is reached then just go to the OFF state again.
I want it to (once the button has been pressed) energise for 6 seconds (relay on) then de-energise for 6 seconds, then depending on how many ON pulses I want continue until the preset figure is reached then just go to the OFF state again.
Thank you so much for your help, a few further questions what are c6 and c7 doing are they tied down to ground/0v, same as ud and Reset? Also are all the p1 connected together?
@Eric
I leave you to answer the OP's questions.
Note: The DIS output of the 555 is shown unconnected (so the 555 only gives one pulse as it stands). Also, shouldn't the CIN input of the counter be grounded?
Thank you so much for your help, a few further questions what are c6 and c7 doing are they tied down to ground/0v, same as ud and Reset? Also are all the p1 connected together?
@Eric
I leave you to answer the OP's questions.
Note: The DIS output of the 555 is shown unconnected (so the 555 only gives one pulse as it stands). Also, shouldn't the CIN input of the counter be grounded?
hi alec,
That method of connecting with the top of the timing resistor connected back to to the output pin is common practice, it gives close to a 50:50 mark/space output.
If required you can add a 10K from the DIS to +V and use it as a secondary output.
I will look at CIN , never had a problem in practice.???
Oops, mea culpa. I had it connected to V+.
I see in the sim you've got the .ic directive which has the effect of making the first pulse width the same as for following pulses. In reality, though the width of the first pulse is ~8.8 secs when the following pulses are 6 sec. Bonus for the cows!
Eric, don't understand that you have a question about this. I'm sure you are aware the good practice is to tie all unused CMOS inputs to ground or V+. Otherwise erratic behavior is a distinct possibility.
Eric, don't understand that you have a question about this. I'm sure you are aware the good practice is to tie all unused CMOS inputs to ground or V+. Otherwise erratic behavior is a distinct possibility.
I often use them without the pin connected, do you have any user experience with problems on this particular device that you could quote.??
The d/s shows the input pins on this IC do have additional diodes etc, that do provide some degree of pull up thru diode leakage.
EDIT:
Perhaps you could post your version of a suitable circuit for the OP.???
Oops, mea culpa. I had it connected to V+.
I see in the sim you've got the .ic directive which has the effect of making the first pulse width the same as for following pulses. In reality, though the width of the first pulse is ~8.8 secs when the following pulses are 6 sec. Bonus for the cows!
Thank you so much for your help, a few further questions what are c6 and c7 doing are they tied down to ground/0v, same as ud and Reset? Also are all the p1 connected together?
I often use them without the pin connected, do you have any user experience with problems on this particular device that you could quote.??
The d/s shows the input pins on this IC do have additional diodes etc, that do provide some degree of pull up thru diode leakage.
EDIT:
Perhaps you could post your version of a suitable circuit for the OP.???
You had question marks so I thought you had some question about that. Guess you were referring to whether anyone had a problem with leaving CIN unconnected.
Certainly a particular CMOS device may allow operation without all the inputs tied, at least for a while, but subtle changes in the circuit, such as from moisture or noise pickup, could lead to erratic (and hard to trace) problems at a latter date. There are reverse-biased input protection diodes to both Vss and Vdd on standard CMOS circuits but I wouldn't depend upon those to provide a definite logic level as the leakage goes in both directions.
Hi
Depending upon which BIN switch type you decide to use, you will require resistor pull ups or downs on the parallel inputs to the 4516... Let me know.?
I will look at your simulation in detail, BUT at first look you have the 4516 LD and CE wired wrong.!