Solar Pumpkins!

[Krumlink]

I asked my family if they wanted some fancy pumpkins, ones that would have Ultrabright burn out your cornea LEDs in them and they said YES! So I came across this schematic on the BEAM circuits website, and I thought that I could use that!

http://solarbotics.net/library/circuits/se_t1_zener.html

PLAN OF ACTION: The plan is to replace the cap with 4 NICAD batteries (4.8V total) and replace the Zener with 4.7V instead of the zener in there. I would replace the motor with ultrabright white LEDs at 20ma (probably about 3 for good display). 600ma NICAD batteries at 240ma MAX. This is far below the maximum that this will need. I want to know if this idea will work. In my idea, it should, but I like asking this forum

 

[Krumlink]

David Cook also has some LED pumpkin's!!!

https://www.robotroom.com/Pumpkin.html

 

[audioguru]

The circuit doesn't have current-limiting for LEDs so they will instantly burn out!

It uses a tiny solar panel to charge the capacitor until its voltage is high enough to turn on the transistors which turn on the motor that discharges the capacitor then stops. Then it starts all over again.

With a battery then there won't be any oscillation so the transistors won't do anything.

It is easy to make an oscillator with two transistors that will blink a few LEDs and is powered from a battery.

 

[Krumlink]

I know to add a resistor to my LED's! Of course I know this!

I have a larger solar panel I am going to be using for this.

How can I make this solar powered? I know I am close to the solution, but I cant quite remember. So basically how can I make a solar powered NICAD Charger that charges batteries, then when they are full discharges them? then when they are empty, they charge again? it seems like that would have worked.

How long would a 0.22F cap last on there? I could use caps too.

 

[Krumlink]

Here is the manual:

LED Pumpkin Manual

2 Main Types of LED pumpkins: Solar Powered (more Expensive) and Battery Powered

Solar Powered Overview:
Uses Special Circuitry to charge its batteries automatically and when full, it will light up, giving off a brilliant display of colors that you choose. It costs more, because of the circuitry special batteries, and the solar panel. The solar panel is made of a special material so it resists breaking and at the same time is flexible. The positive aspect is that you are using the Sun’s energy to charge your Pumpkins, which saves batteries for other uses.

There are several types of Solar Pumpkin’s you can choose from:
· Constant ON display
· Flashing Display (slow, medium, fast)
· Twinkling Display

Solar Powered Overview:
Uses Standard AA batteries and an internal switch for manual switching on and off the pumpkin display. Contains the same LED’s as the Solar Power Pumpkins to give off a brilliant display.

There are more types of Battery Pumpkin’s you can choose from:
· Constant ON display
· Flashing Display (slow, medium, fast)
· Twinkling Display
· Fire effect Display (resembles a twinkling fire)
· Brilliant Display (contains Different Colored LED’s for an amazing display)

How to install into your pumpkin:
The installation Process is very easy. The LED Pumpkin Works better when in an artificial or white pumpkin, but will still give amazing results in any pumpkin.

STEP 1. Take your Pumpkin Kit out and lay it out and make sure you have all your components.

STEP 2. Place the Pumpkin LED inside your pumpkin from the top (for real pumpkins) or the bottom (artificial pumpkins).

STEP 3: For battery operated pumpkins, turn on the internal switch when you are ready to activate the Pumpkin Display. The LED’s will be very bright, so be careful! Turn switch off turn off the Pumpkin LED display. For Solar Pumpkin’s, Place the Solar panel in a bright sunny spot and wait for the batteries to be fully charged. The Indicator LED will turn on, showing you that the batteries are fully charged and ready to turn on. Press the switch to the on position to turn on and off the LED’s. When the batteries are fully charged, disconnect the Solar panel from the unit via the socket.

 

[audioguru]

Are you trying to make a dim solar garden light?

 

[Krumlink]

no, all I want is to have a solar engine!!!

it charges up and when it is full it discharges it and acts as a battery for the circuitry to power a LED. How can this be that hard? Should I just use the solar circuit above?

 

[Ambient]

maybe a pic 10f with A/D with an independant Vref? A pic that wakes up every 10 seconds to check the voltage and either turn a transistor on or off would consume a negligible amount of current, so when the battery is not charged it could run off the solar cell power. You could even set it up with a photodiode on a comparator input for only allowing it to turn on at night, thus allowing the battery to charge all day. You can hook up the PIC's power to the battery and the battery would be isolated (when the colar cell is lower voltage) by a diode. MIGHT work, I just came up with it off the top of my head, I have not put it on paper.

I have never tried this, but that is how I might approach it, as I like using PIC at the moment.

 

[signal]

You should check out the nocturnal solar engines like the one at the top of **broken link removed**. The solar cell and the transistor act as a dark detector, filling the 1F aerogel super capacitor when there is light and powering the LED when it gets dark.

I'm not sure how long it will last with a super bright LED though but maybe this circuit is a start.

I'm making this one this year.

 

[audioguru]

You need a transistor or two to turn off the LEDs in the daytime when the battery is charging.

If your solar panel is big and expensive enough then it will charge two AA Ni-MH cells in 6 hours. Then the two AA Ni-MH cells can power 25 red LEDs through a current-limiting resistor for 5 hours.

A smaller solar panel will charge two AAA cells which will power 7 red LEDs for 5 hours.

Blue and white LEDs need a supply voltage much higher so 4 Ni-MH cells must be used, or a voltage stepup circuit must be used.

The LEDs will not do anything but glow like a simple garden light.

 

[Krumlink]

Hmmmm

Could I just put the LED's and Resistors in place of the motor on that circuit? I really dont want to get this too complicated, because I dont want it to

I am just learning PIC and C code, so a micro is out of the question.

When I order meh parts I will experiment with the solar engine circuit and make some cool stuff that You will get to see. Maybe I will put one of my massive caps in a circuit (26,000uf at 50 Volts ) and show you guys under projects...

 

[audioguru]

All the solar engine circuit does is pulse the motor for a moment every few minutes. Then it would blink an LED every few minutes. Most of the time the motor or LED is off while a tiny solar cell charges the capacitor.

26,000uF is not much. If it is charged to 5V then it would supply 25mA to a 2.5V LED through a current-limiting resistor for only a few seconds, dimming the entire time.
The solar engine circuit has hardly any power and it uses super capacitors with values in Farads (1,000,000uF and more).

 

[signal]

Hmmmm

Could I just put the LED's and Resistors in place of the motor on that circuit?

That is an LED instead of a motor on that circuit.

 

[Krumlink]

uh no it isnt.

A M inside of a circle is a motor...

 

[Krumlink]

Fine then I want a solar powered NICAD charger that then discharges when it is full.

 

[signal]

uh no it isnt.

A M inside of a circle is a motor...

Are we both talking about the top schematic on **broken link removed**? If not, sorry!

 

[audioguru]

Fine then I want a solar powered NICAD charger that then discharges when it is full.

Then it is called a "solar garden light". My electrical utility company was giving them away. I got 10 of the amber ones. They charge all day then glow dimly for a few hours each night.

Then I bought 4 white ones on sale and they are much brighter. I bought 5 that slowly change from red to blue to green over and over all night. One got wet inside and stopped. I will fix it.

I bought a solar panel on sale that is made to trickle-charge a car battery. The list price is $30.00 but I got it for only $10.00. It can charge eight AA Ni-MH cells in 25 hours then they could power 3 very powerful LEDs for about 3 hours.

 

[Krumlink]

Is there a schematic I can look at?

 

[audioguru]

Is there a schematic I can look at?

Look in Google for Solar Garden Light Circuit. There are links to hundreds of them. Most use a small solar panel to charge 1 or 2 Ni-Cad AA cells. Then a dim LED glows at night for a few hours.