Radio Bright LED
This website is about a radio controlled bright LED. This device is useful for finding your way in a dark room before you trip over something.
The range is about 7 metres.
You can see the video that the LED is turns ON and does not remain ON after I release the transmitter button.
I did not make the receiver circuit. I ordered a few standard RX480E QIACHID boards from eBay. They are only $5 each. The transmitter was not included in the envelope that I received. Thus I had to borrow from a friend.
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Supplies
Components: small bright LED/low current bright LED - 3, solder, matrix board, 1 mm thickness metal wire - 50 cm, 5 volts 7805 voltage regulator, insulated wire (red and black), 9 V battery harness, 9 V battery. 1 kohm resistor - 2 (low power).
Tools: soldering iron, pliers, wire stripper.
Optional components: heat sink, heat transfer paste, rechargeable 9 V battery.
Optional tools: multi-meter.
Make the Circuit
I did not use the most appropriate matrix board for my circuit because it contains rows of metal PCB tracks instead of separate holes.
The 7805 voltage regulator is needed to supply power to the receiver board. You can see in the photo that the input is the lower red wire and the output (that is supplying to the receiver board) is the red cable above with the ground wire connected to middle (centre) pin.
I connected the LED in series with 1 kohm resistor to Vt pin of the receiver board. That means the maximum LED current is equal to:
IledMax = (Vs - Vled) / Rd
= (5 V - 2 V) / 1,000 ohms
= 3 V / 1,000 ohms = 3 mA
We must be careful not to burn the output of receiver board.
I actually burned one the receiver boards because did not spend enough time removing the row of PCB tracks to prevent the voltage regulator pins from shorting. However, I did not burn the 5 V voltage regulator. The one that you see in the photo is the second one.
My bright LED could be brighter. I actually did not have a bright LED in stock. I used a blue LED.
Testing
The transmitter is a standard transmitter that is used for the receiver board. You can see in the video how I activated the board.