First time poster here so I apologize for any dumb questions.

I really don't know much about circuits but am willing to learn a little, although I don't have too much time as I want to complete this project in time for the Summer heat.

I want some sort of push button to activate a solenoid and for it to remain open for about 20 seconds or so and would run on a 9v battery. Basically, I'm making a super duper bike wash for my kids and would love to add this modification to it. Not only would it be really cool for them to 'activate' the bike wash, but it would also save on the water bill when they aren't using it.

I've read a little about 555 circuits, but don't know much about them or how to size resistors or capacitors. That's why I've come here to the professionals pleading for some help.

Also, in the future I would like to have this scenario: Child pushes the button and the water starts on the misters, child rides bike through misters then bike rolls over some sensor to start part two of the wash, while part one ends. I don't even know what part two is yet!.... If you have any ideas of how to do this or even what to use for part two or three let me know. I'll first concentrate on just the timing aspect for the entire wash system.

Thanks!

 

Find a washing machine that is being thrown out. It has all the parts you need, switches, timer, solenoids, hoses etc.

 

Darn. I've recently scrapped a couple but haven't kept the timers or switches or solenoids... I guess I'll be on the lookout for another one. Any other ideas? Can I purchase these things and make my own circuit?

I'm also thinking, maybe the solenoid cannot be opened with only 9v. Again, I have no knowledge of circuits so please be patient.

If I do have the parts to a washer, how would I set the time frame for only 20 seconds or so and also add a push button to start the process?

 

Find an inexpensive water sprinkler electronic timer. These contain a small DC motor that opens and shuts the water flow and is battery operated. This is the part you are after, not the electronics. We will show you how to build the electronics to do what you want.

Here is an example:

http://www.homedepot.com/p/raindrip-Analog-Electric-Water-Timer-R672CT/100182581#.UbxhYdhTHTo

 

Great. That raindrip one from H.D. has pretty poor reviews - most of the valves were stuck within one season. How do either of these look as far as functionality and what I need it to do?

http://www.homedepot.com/p/Toro-Blu...Hose-End-Timer-53746/100088778#specifications

http://www.lowes.com/pd_186-74985-6...tId=3086687&Ns=p_product_price|0#BVRRWidgetID

 

It is difficult to judge until you open it and find out.

Now as far as your own controller goes, there are two approaches. You can do it with a pair of 555 timer chips. But as you add stage 2 and stage 3 the complexity grows with each added stage.

Or you can go with a one chip solution using a programmable microcontroller. Every time you come up with a new idea all you have to do is change the program. Of course, you know which solution I would choose. Here is an excellent opportunity to learn how to program a microcontroller.

My recommendation would be to get the TI MSP430LaunchPad and get cracking.
This is going to set you back $10.

 

Hmmm.... I know I'd love to go the LaunchPad route, but something is telling me I may never add additional stages. Most likely I'll have everything running at the same time. Part of that is the price of adding additional stages.

If I have time and more money in the future for this bike wash, would it be possible to switch over to using the LaunchPad?

Lets go with the pair of 555 timer chips and the assumption I'll have everything running at once.

So where do we get started? Do I need to buy one of the sprinkler timers first before I find out what type of 555 timer I need?

 

Interesting.

Without putting too much thought into it, I'd follow MrChips advice using the following:

If you only need to control the water for one stage, take a look at this.

If you want to control water for two stages independently, then look at this.

You can take it apart and access the button contact for the manual operation (turns water on and off). Solder some wire to the pads and run them to the output of a 555 monostable circuit. I think you'll be able power the 555 circuit from the battery pack inside the unit.

Take a look here for how a 555 monostable works.

If you want to get your hands dirty right away, make the 555 circuit and connect the output to an LED to test. Let us know if you have any questions. I can throw together a schematic if it would help.

 

Hi everyone. As suspected, this part of the project has been put on hold. I'm now getting my kids ready to start school soon and we have birthdays and are also moving! However, I did find an awesome find in my scrap pile: A solenoid for a washing machine - one water input with two output solenoids. Only problem is they are 120v so I can't simply use a 9v battery. However, I'm pretty happy about the find.

I'll post more and ask more questions when things settle down later this year - actually probably in late spring or early summer.

Thanks for all the help thus far.