Supercapacitor USB Light
Intro: Supercapacitor USB Light
For those who never heard about supercapacitor, you can check for more info about supercapacitor here. Supercapacitor is basically a capacitor with very high capacity, and the capacity rating is normally around few Farads. With the “super” capacity, it basically can store a lot of charge, and I am going to use the “super” capacity to store charges for a 5mm LED. Let’s see how long will the 5mm LED last.
STEP 1: Components Needed
The components you will need for this project is basically a supercapacitor (I am using 5.5V 0.1F supercapacitor which I bought from Farnell), a White LED, a 1K Ohm resistor and a USB male connector (I get this from an broken pendrive).
STEP 2: Supercapacitor Polarity
Make sure you know the polarity of the supercapacitor, or refer to its datasheet
STEP 3: Soldering
The first step is to cut the 2nd and 3rd pin of the USB male connector, we will need only the 1st and 4th pin (5V and 0V pin).
Then solder the negative pin of the supercapacitor to the 4th (0V) pin of the USB male connector.
Now, try to connect the positive pin of the supercapacitor to the 1st pin (5V). For the connection I am using a resistor leg.
Then solder the negative pin of the supercapacitor to the 4th (0V) pin of the USB male connector.
Now, try to connect the positive pin of the supercapacitor to the 1st pin (5V). For the connection I am using a resistor leg.
STEP 4: Soldering
Next, connect the positive pin of the White LED to the 1st pin (5V) of the USB male connector.
Finally, connect a 1K resistor from the negative pin of White LED to the 4th pin (0V) of the USB male connector.
Finally, connect a 1K resistor from the negative pin of White LED to the 4th pin (0V) of the USB male connector.
STEP 5: Schematic
Please check the diagram below for the complete schematic. You are actually free to use higher Farad supercapacitor, but voltage rating must be larger or equal to 5V, and you can have your creative way to connect all the components together.
STEP 6: Testing
Now, plug it to your computer for around 10-30 seconds to charge up the supercapacitor.
You should see the White LED turned on (if it doesn’t turned on, there are some mistake in the connection), then after 10-30 second, you can unplug it and you should have around 10 minutes of the LED light.
Source http://www.bustatech.com/supercapacitor-usb-light/
You should see the White LED turned on (if it doesn’t turned on, there are some mistake in the connection), then after 10-30 second, you can unplug it and you should have around 10 minutes of the LED light.
Source http://www.bustatech.com/supercapacitor-usb-light/
STEP 7: Circuit Update
Circuit Update (6 Oct 2010)
I made some changes to the circuit, adding another resistor to limit the current consumption from USB port, and an ON/OFF switch to control the white LED.
The circuitry is simple, when you plug it into PC, the USB port will start charging the Supercapacitor, and there is a 10Ohm resistor (R1) limiting the current from USB port to 5V/10Ohm = 500mA maximum, but the R1 will also slow down the charging time. For large capacitance Supercap, you might need to let it charge for around 1 to 2 minutes. At the LED side, the S1 will let you turn ON or OFF the LED, and the 1KOhm resistor (R2) is to limit the current for the LED. If you use smaller value for R2, like 330Ohm, it will increase the brightness of LED but will also reduce the operating time of the LED for one charge. By using larger value for R2, you will increase the operating time, but reducing the brightness. I found 1K to be the balance value for the brightness and operating time.
Talking about the brightness and the operating time balance, I created another circuit that let you choose 3 level of brightness.
I made some changes to the circuit, adding another resistor to limit the current consumption from USB port, and an ON/OFF switch to control the white LED.
The circuitry is simple, when you plug it into PC, the USB port will start charging the Supercapacitor, and there is a 10Ohm resistor (R1) limiting the current from USB port to 5V/10Ohm = 500mA maximum, but the R1 will also slow down the charging time. For large capacitance Supercap, you might need to let it charge for around 1 to 2 minutes. At the LED side, the S1 will let you turn ON or OFF the LED, and the 1KOhm resistor (R2) is to limit the current for the LED. If you use smaller value for R2, like 330Ohm, it will increase the brightness of LED but will also reduce the operating time of the LED for one charge. By using larger value for R2, you will increase the operating time, but reducing the brightness. I found 1K to be the balance value for the brightness and operating time.
Talking about the brightness and the operating time balance, I created another circuit that let you choose 3 level of brightness.
STEP 8: Circuit Update
In this circuit, the charging and USB port part is still the same, but I add in S2 and R3 at the LED side. So, the S1 and R2 will still function like the previous one, that by switching on S1, you will get the 1KOhm resistor brightness. By adding S2 and R3, it means that if you switch on S2, you will get 330Ohm brightness, which is brighter than 1KOhm brightness, because the resistor that limiting the LED current is now smaller and higher current on the LED means higher brightness. I say you will have 3 level brightness, so, the third level brightness is by switching ON S1 and S2 at the same time.
When S1 and S2 is being switch ON, the R2 and R3 form a parallel pattern, and you need some calculation to get the total resistance for the White LED.
The total resistance from the parallel of R2 and R3:
1/R = 1/R2 + 1/R3
R = 1 / ( 1/R2 +1/R3 )
R = 248.12Ohm
So, the total resistance at the White LED if you turn ON both S1 and S2 is 248.12Ohm which is 3rd level of brightness for the White LED.
- 1st level (S1 ON) – 1KOhm Brightness
- 2nd level (S2 ON) – 330Ohm Brightness
- 3rd level (S1 and S2 ON) – 248.12Ohm Brightness
Source: http://www.bustatech.com/supercapacitor-usb-light/
When S1 and S2 is being switch ON, the R2 and R3 form a parallel pattern, and you need some calculation to get the total resistance for the White LED.
The total resistance from the parallel of R2 and R3:
1/R = 1/R2 + 1/R3
R = 1 / ( 1/R2 +1/R3 )
R = 248.12Ohm
So, the total resistance at the White LED if you turn ON both S1 and S2 is 248.12Ohm which is 3rd level of brightness for the White LED.
- 1st level (S1 ON) – 1KOhm Brightness
- 2nd level (S2 ON) – 330Ohm Brightness
- 3rd level (S1 and S2 ON) – 248.12Ohm Brightness
Source: http://www.bustatech.com/supercapacitor-usb-light/
130 Comments
makerfam 7 years ago
would a 0.1 farad capacitor work? It's the cheapest one- 20 for $4
remusfillis 8 years ago
How long does the light stay on?
pablotbbt 9 years ago
I use a capacitor of 10 volts ?
jgilbride 8 years ago
According to step 5, yes.
pmshah 8 years ago
Look up AliExpress. You can get up to 4 F capacitors at bargain prices, delivered free any where in the world.I have a bunch of old ball point pens with built in batteries and single led torch. These originally cost me like 5 ¢ each. Practically don't have to spend any money.
MarosP 9 years ago
A white led would probably handle 5V (+- 0.5V), and would be nicely bright. If you don't want to risk it, still, 1K ohm resistor seems to be too much.
buckminsterfullerene 13 years ago
Mateo JCF 9 years ago
Awesome! I wanted to incorporate something like this into a bracelet but didn't want to use a battery! Now I don't have to! Thank you a lot for making this!
bustatech 13 years ago
madmanmoe64 13 years ago
jacobrb95 10 years ago
https://www.sparkfun.com/products/9609
busterdavidson 12 years ago
madmanmoe64 12 years ago
didibemi 11 years ago
petalee 12 years ago
wessamer 12 years ago
can have the circuit you made to have the design
thanx
dragon_shadow88 13 years ago
PS, there are supercap that has a capaticanse of 7F but only 2V , add a hand generator to charge it and a 1,5V LED driver and ingoy your hand rechargeable flash light.
sorry for bad english, I'm from Serbia :)
fjr_scoot 9 years ago
I am from the US, and your English is better than most Americans'. Please do not apologize. :-)
Callum Snowden 13 years ago
htetkyawlwin 12 years ago