Tabletop Tree Lights

Description: A garland tree was enhanced by adding blinking LEDs. The tree is a simple garland wrapped around a plastic frame, purchased at a discount. Although it could have been made from scratch, the cost-effectiveness of the purchase was appealing. The tree adds vibrant color to a camper but lacks lighting. Historically, Christmas trees have been illuminated, prompting the project to utilize older LEDs and scrap wire. The design includes a battery, switch, and LEDs, with the additional goal of creating a blinking effect with adjustable speed. The circuit employs a 555 timer IC and a 74393 counter IC to generate varying blink speeds. To achieve a random blinking pattern, the outputs from the counter are fed into a 7447 BCD to 7-segment decoder, which controls nine LED sinks. This setup incorporates 54 LEDs arranged in parallel and series configurations, resulting in a complex wiring layout concealed by the garland. A 7.2V NiMH rechargeable battery powers the circuit, which is mounted on the tree's frame. The blinking patterns, while not entirely random, provide a satisfactory visual effect, though alternatives using microcontrollers could enhance randomness and control.

The circuit design consists of several key components that work together to create a visually appealing and functional LED lighting system for the garland tree. The 555 timer integrated circuit (IC) serves as the primary oscillator, generating a pulse-width modulation signal that controls the blinking of the LEDs. The frequency of this blinking can be adjusted using a potentiometer, allowing for customizable effects.

The 74393 counter IC is utilized to divide the output frequency from the 555 timer, creating multiple output signals at varying rates. This division is crucial for achieving the desired blinking effect, as it allows for different patterns to emerge from the LED arrangement. The outputs from the counter IC are then routed to a 7447 BCD to 7-segment decoder. This decoder translates the binary-coded decimal inputs from the counter into an output that can drive the LEDs in a unique manner, creating the illusion of randomness in the blinking patterns.

The nine LED sinks are configured in a way that maximizes the visual impact of the lighting. Each sink consists of three parallel strings of two series-connected LEDs, resulting in a total of 54 LEDs. This configuration not only provides ample illumination but also distributes the current effectively, ensuring that each LED receives the appropriate voltage and current for optimal performance.

The power supply for the circuit is a 7.2V NiMH rechargeable battery, which offers a reliable and portable source of energy. The battery is securely attached to the frame of the tree, ensuring that it remains out of sight while providing sufficient power for the LED array. The circuit is designed to be user-friendly, with a switch that allows for easy activation and deactivation of the blinking feature.

While the current design produces satisfactory results, there is potential for further enhancement. Implementing a microcontroller could facilitate the use of a pseudorandom number generator, significantly increasing the variety of blinking patterns available. Additionally, integrating output expansion registers would allow for the control of more LED strings, enhancing the overall lighting effect. The speed of the blinking could also be fine-tuned through digital inputs, providing users with the ability to adjust the lighting to their preference. Overall, this project exemplifies a creative and resourceful approach to enhancing holiday decorations with technology.A cheap garland tree and fill it full of blinking LEDs. The tree shown is a cheap garland wrapped plastic frame from Walmart. It could easily be made, but I didn`t feel like taking the time to do so. Besides, I got in on clearance, so I might not have been able to make it as cheaply as I bought it. Plus, what would I do with the left over materials They`d probably make a nice a dust collector. On its own, this tree is a wonderful splash of bright color in our drab camper, but it could definitely be improved. I mean, what kind of Christmas tree doesn`t have lights on it Even before electricity was invented, people lit candles on their trees to illuminate them.

This seemed like a perfect project to get rid of some older LEDs I had to make room for new stock. It would also be a good use of my ever increasing pile of scrap wire pieces. All it would need is a battery, switch, and some LEDs, but of course that isn`t all I did with it. I wanted the LEDs to blink, and I wanted to control the speed. The resulting circuit is far from perfect, but it was a great first attempt at bringing a bit of Christmas cheer to a pair of nomads. I really wanted as random of a blinking pattern as possible using only a few components I had lying around.

The obvious choice for controlling the speed would be a 555 timer IC in combination with a potentiometer, the challenge was creating a simple randomizing circuit. To start, I went with a 74393 counter IC to split the 555 output into varying speeds. I knew an easy way to create a lot of outputs would be to use some type of decoder, but using standard binary counting would create somewhat logical patterns.

To create the seemingly random blinking, I ran the counter outputs into the inputs of a 7447 BCD to 7 segment decoder. This chip combined the abnormal BCD count with the strange outputs needed to drive a seven segment display and has the following input/output relationship.

The seven decoder outputs were used in combination with two of the counter outputs to form nine LED sinks. Each bank consisted of three parallel strings of two series LEDs for a total of 54 LEDs and 108 pieces of wire to connect them all together.

The inside of the tree is a total bird`s nest of random wires, but this is all hidden nicely by the garland. This build took a bit of time, but only because it got more difficult to glue the LEDs in place and shove more wire into the tree as time progressed.

It was actually really easy, just time consuming. I used a rechargeable 7. 2V NiMH battery as a power source. The battery and circuit were attached to a couple of the upright frame posts on the tree. Although this tree works really well, the blinking is not all that random. The patterns are quiteunpredictableat first, but considering there are only nine total outputs working off of a four bit counter, it repeats itself after sixteen flashes (the highest number you can count with four bits is 24, or 16). This isperfectlyfine for my purposes, but if a truly random output is desired, it could easily be done with a microcontroller using apseudorandom number generator.

This could put the output combination into the thousands as opposed to the teens. In addition to the MCU, a few output expansion registers could be used to increase the number of LED strings which can be individually controlled. The speed could be controlled by apotentiometerconnected to the ADC or a couple of digital button inputs signifying "speed up" or "slow down.

" Another good addition to the circuit would be a switch to turn the blinking on or off. Currently, only