Have one LED working with a ultrasonic sensor, how to now expand to an LED strip

Other Hardware LEDs and Multiplexing
1

I have a SR04 ultrasonic sensor controlling the brightness of 1 LED.

I now want to expand this simple circuit to control a 12v LED strip (not RGB 4 wires just 2 wires).

Slightly confused on how the wiring and power works for this, ive only done stuff with the arduino powering LED's

Here is teh current setup which works fine (albeit the sensor readings f#which jump around a lot)

1024×768 211 KB

2

How long is the strip? Or, more importantly, how many leds on the strip?

Leds need around 20mA each, perhaps as much as 30mA. But on a 12V strip they are arranged as groups of 3 in series. Multiply the current by the number of led groups to get the total current required. If it is below around 600mA (maybe 60~90 leds) then a small transistor will be ok, such as bc337. For more leds, a logic level MOSFET would be needed such as stp16nf06l.

3

PaulRB:
How long is the strip? Or, more importantly, how many leds on the strip?

Leds need around 20mA each, perhaps as much as 30mA. But on a 12V strip they are arranged as groups of 3 in series. Multiply the current by the number of led groups to get the total current required. If it is below around 600mA (maybe 60~90 leds) then a small transistor will be ok, such as bc337. For more leds, a logic level MOSFET would be needed such as stp16nf06l.

16Ft/5M 5050 SMD Waterproof 300 LED 395-405nm UV Light Blacklights

Voltage:DC12V

Strip type:SMD5050

LED Watt:0.2W/pcs

Power Consumption (W/m):11.52W/m

LED Quantity:300 LEDS/5M

thanks

4

Gonna need a bigger transistor. AOI510 or AOI508 from Digikey.com
"UV Light Blacklights"
11.52W/m x 5M = 57.6W / 12V = 4.8A.
AOI508 o AOI510 will handle that no problem without dissipating much heat in the device.
Pdevice = IIRds. 4.84.8.0045ohm (4.5V Vgs, up to 20A) = 100mW
http://www.digikey.com/products/en?keywords=aoi508

5

CrossRoads:
Gonna need a bigger transistor. AOI510 or AOI508 from Digikey.com
"UV Light Blacklights"
11.52W/m x 5M = 57.6W / 12V = 4.8A.
AOI508 o AOI510 will handle that no problem without dissipating much heat in the device.
Pdevice = IIRds. 4.84.8.0045ohm (4.5V Vgs, up to 20A) = 100mW
AOI508 Alpha & Omega Semiconductor Inc. | Discrete Semiconductor Products | DigiKey

thanks, ideally i want to order something from ebay as I need it here quickly and cheap postage, would something like this do?

http://www.ebay.co.uk/itm/4-X-International-Rectifier-Infineon-IRLB8721PBF-30V-62A-N-Channel-MOSFET-/162396224060

6

I don't know where "here" is, but surely there are reputable parts distributors that will ship to you? I won't buy any electronics from ebay - too much counterfeiting, fake, used, scrapped parts being sold as new.

7

I did buy a used Dynaco ST-70 stereo tube amp, but I got to pick it up locally in person and see if before I drove off with it.

8

CrossRoads:
I don't know where "here" is, but surely there are reputable parts distributors that will ship to you? I won't buy any electronics from ebay - too much counterfeiting, fake, used, scrapped parts being sold as new.

UK based

the problem with all the electronic distributors that ive browsed before is their shipping charges are so much more than the actual parts.

This is just a small project so im not too fussed about the quality of the parts, just need a prototype working for now.

9

I've never used that exact model, but from the spec, those MOSFETs you gave the link to sound ok.

10

PaulRB:
I've never used that exact model, but from the spec, those MOSFETs you gave the link to sound ok.

thanks, should be here Friday, will report back

11

The mosfet arrived and got it setup and my prototype is now working :slight_smile:

Here is a low quality, very short video of it up and running - Ultrasonic Sensor Controlling UV LED Poster (low quality video for now) - YouTube

thanks for the help everyone