Digital Clock that Sprays Water

[DDJ2011]

Hi All,

I have been reading the forums for a while, and asking for help for issues, but my specific aim is to build a digital alarm clock which - if you don't hit the off button quickly enough - sprays water at you. This is a school engineering project - it doesn't count towards my exams, just for engineering club!

Today many people helped me to find a 12V to 5V power supply schematic (thanks!) but I would appreciate some more help with the basic schematic for the clock and split power supply.

The split power supply requires 5V for the PicAxe control circuit and 12V for the water pump. My basic schematic is shown below - not sure if I need to consider anything else for the 12V part of the circuit:



For the PicAxe part of the circuit I have an 18M2 that I want to link to a DS1307 RTC. I have attached a basic schematic below. I know there are lots of things missing, I just want to get the clock working first. I think the circuit is right (?) but am not sure about the circled OUT pin 7 on the RTC - do I need to connect this to anything on the 18M2?
The three LEDs will (in this version) show the time by flashing (LED1 = OK, LED2 = hours, LED3 = mins). In a later version I will use the serial in/out ("circled" with a rectangle!) to run an OLED display from Rev-Ed. I just need to practice my soldering before I assemble the OLED.

Does the basic circuit look OK - I have looked at the forums and included as much as I can find.



All help gratefully received.

DDJ

 

[DDJ2011]

Sorry - have updated Power Supply diagram to include a protecting diode.

 

[bluejets]

Sorry - have updated Power Supply diagram to include a protecting diode.

View attachment 10373

Don't know what the two 1N4001 diodes on the input are supposed to do.

 

[SAborn]

I dont think i like the idea of "A Wet Dream" alarm clock.

The diode to the motor is not needed, but a diode should be placed across the motor in reverse for emf.

The out pin of the DS1307 is not needed to be connected, but it is handy to place a led on the pin to show the RTC is running, it will give a 1hz flash of the led.

 

[techElder]

So your motor just runs all of the time?

 

[Bill.b]

Hi DDJ Here is a clock schmatic and code for a picaxe 18m2 using then AXE 033y OLED module.
this code used I2C to commumicate with the display and the DS1307 RTC.

if you are using the AXE133 you may have to comvert the I2c command for the display to serial commands




View attachment i2clcdCLOCK18m2.txt

regards Bill

 

[IronJungle]

Two comments:
- It looks like your motor is going to run all the time. You will need a MOSFET or a transistor that uses the PICAXE as an input to control the motor.

- You have 330K resistors on your LEDs. Is that a typo?

Good luck and be sure to take a few pics of the end project to post.

 

[eclectic]

@DD
Just in case you (or others viewing)
haven't seen this:
http://www.picaxe.com/docs/axe110_i2c.pdf
Page 1 for the clock.
e

 

[DDJ2011]

Thanks to the many people for the help so far!

@bluejets - this thread shows the process of getting to a good power supply schematic - many thanks to everyone who helped with that!

@SABorn - more of a wet nightmare I suspect. Thanks for the diode tip for the motor. In my PicAxe circuit I now have an LED to flash at 1Hz from the DS1307 OUT pin.

@Texasclodhopper (and anyone else who was confused) - sorry if I was not clear, the original schematic was not meant to represent the actual circuit, but more to see whether I needed to add anything to the 12v part of the circuit. My new circuit shows the 12v control parts, but still specifically excludese the picaxe circuit which I will show in a later reply to this thread!

@Bill.b - thanks for the schematic and code. I don't have the LED with clock built in so my circuit will be different to yours, but the code is really useful.

@IronJungle - yes the 330k was a typo...fixed now

@eclectic - thanks for that link - really useful.

------------------------------------------------------------------
Here is the latest schematic for my power system. Please note that the PicAxe part of the circuit will be addressed in another reply to this thread.



Reading other threads (eg this one) it looks like I need to use a MOSFET rather than a Darlington driver as I originally planned to drive the motor. Can anyone advise me - or provide a link - on how to select a suitable part for the circuit?

I will buy a water pump from here - about the only place I can find a reasonably priced low voltage DC water pump, but if anyone has any other suggestions I would be very interested.

Again, thanks for your help - I'm trying to accumulate knowledge as quickly as I can, but without the help of many people on this forum I wouldn't be getting anywhere!

DDJ

 

[Buzby]

the only place I can find a reasonably priced low voltage DC water pump, but if anyone has any other suggestions I would be very interested.

Something like this aquarium gadget is less than half the price,

http://www.ebay.co.uk/itm/Aquarium-Algae-Tube-Filter-Water-Pump-Cleaner-Battery-/300561652853?pt=UK_Pet_Supplies_Fish&hash=item45fadedc75

or this,

http://www.ebay.co.uk/itm/indoor-water-fountain-/140696222916?pt=UK_Home_Garden_Decorative_Accents_LE&hash=item20c225fcc4

and even cheaper is a car windscreen washer pump.

For a totally different method think on this.

On the website for the Murata Microblowers that Marcwolf found, there is a video of one being used to power a jet of water.
http://www.murata.com/products/micromechatronics/demonstration/microblower/index.html

With some bits of aquarium air tubing, a T-joint, and a non-return valve, you could use the microblower to power repeated jets of water.
As well as being a well cool bit of kit, you can get a free sample from Murata if you follow the links on their website.

Good luck, it's a great idea for a project.

Cheers,

Buzby

 

[fritz42_male]

How about using a modified inkjet cartridge - the ones with built in piezo jets?

Something like this aquarium gadget is less than half the price,

http://www.ebay.co.uk/itm/Aquarium-Algae-Tube-Filter-Water-Pump-Cleaner-Battery-/300561652853?pt=UK_Pet_Supplies_Fish&hash=item45fadedc75

or this,

http://www.ebay.co.uk/itm/indoor-water-fountain-/140696222916?pt=UK_Home_Garden_Decorative_Accents_LE&hash=item20c225fcc4

and even cheaper is a car windscreen washer pump.

For a totally different method think on this.

On the website for the Murata Microblowers that Marcwolf found, there is a video of one being used to power a jet of water.
http://www.murata.com/products/micromechatronics/demonstration/microblower/index.html

With some bits of aquarium air tubing, a T-joint, and a non-return valve, you could use the microblower to power repeated jets of water.
As well as being a well cool bit of kit, you can get a free sample from Murata if you follow the links on their website.

Good luck, it's a great idea for a project.

Cheers,

Buzby

 

[AndyGadget]

This is what you need for your 'directed fluid repose nullifier', and it's already got an adjustable sprayer head. 3V powered and easy to modify. I've used one in a Picaxe powered vivarium lighting / heating / humidity controller.

http://www.ebay.co.uk/itm/GARDEN-HOUSE-SPRAYER-MISTER-POWERED-/170778593843?pt=UK_Home_Garden_Garden_Plants_Weed_Pest_Control_CV&hash=item27c3328a33

 

[DDJ2011]

This is what you need for your 'directed fluid repose nullifier', and it's already got an adjustable sprayer head. 3V powered and easy to modify.
http://www.ebay.co.uk/itm/GARDEN-HOUSE-SPRAYER-MISTER-POWERED-/170778593843?pt=UK_Home_Garden_Garden_Plants_Weed_Pest_Control_CV&hash=item27c3328a33

Great ideas! Thanks for those everyone. I have written to see whether I can get a sample of the microblower (fingers crossed) and have ordered the 3V sprayer as well. This will make my life a lot easier (and cheaper)!!!!