20 lights latching two at a time

[Henners]

hi all

What I would like to do is have my garden path lights coming on only at night, which is not a problem. the bit i need help with is as follows.

There are 20 lights (12v 4W) which I would like to latch on two at a time, 1 and 11 then 2 and 12........ up to 10 and 20. Stay on for 5 minutes then reset waiting to be activated again.
I have an idea for the 5 minute timing circuit (good old 555 with a relay) it's the staggered part i don't know where to start.
If anyone can point me in the right direction or where to find any info it would be most appreciated.

Major Brownie points to be earnt with my wife if you can help sort this out.

Thanking you in anticipation
Henners

 

[Screech]

How About :
Charge Up A Capacitor And Input It To An Lm3914, (10 Output Voltage To Bar Graph Display.)

Interface The 10 Outputs Anyway You Want To The Lights.

Time It All With A 555 Timer.

 

[dboyer]

Hm. 4W/12V = .33A? I would drop the relays - seem to be expensive overkill to me. 10 mosfet switchs should be sufficient, and shouldn't set you back more than $5. The 555 seems like a good idea - it will allows you set the frequency (or duty cycle) with a simple RC circuit. I think a shifter would work well for controlling which lights are lit, but I only know of ones that come in 4 and 8 bits, complicating things slightly. If you had 8 sets of lights, however, it would be easy to set the shifter up to just shift left on every pulse from the 555, and use the outputs to trigger the mosfets. probably less than $10 for parts, all told.

 

[Roff]

Hm. 4W/12V = .33A? I would drop the relays - seem to be expensive overkill to me. 10 mosfet switchs should be sufficient, and shouldn't set you back more than $5. The 555 seems like a good idea - it will allows you set the frequency (or duty cycle) with a simple RC circuit. I think a shifter would work well for controlling which lights are lit, but I only know of ones that come in 4 and 8 bits, complicating things slightly. If you had 8 sets of lights, however, it would be easy to set the shifter up to just shift left on every pulse from the 555, and use the outputs to trigger the mosfets. probably less than $10 for parts, all told.

I just assumed these were AC lights. If so, they could certainly run on DC, but if you used MOSFETs, you would need a 12 volt, 7 amp power supply (or battery).
I had the same thoughts about shift registers.

 

[Henners]

Thank you all for your input.
I have some questions and answers as my knowledge of electronics is of a hobby nature and fairly basic.

Hi Screech
Thanks for your tip about the LM3914, but why charge up a capacitor

Hi dboyer
The reason why i was going to use relays is, because of the distances involved i was going to use a multitap transformer to allow for the voltage drop that will occur. therefore i would only need to set one voltage to activate the relays. Or can i still achieve thsi with MOSFETS

Hi RonH

Yes you are right the lights are A/C but can rectify them to DC.
I set them up in place at night with an alarm battery to get the light distribution right so i know they will work on DC.

About shift registers.. will this give a running light effect rather than turn them all on one at a time. What i'm after is a runway light effect so they come on one (or in my case two) at a time but all stay on for the allocated time.


P.S.
I know i could just light the lot up at once but where's the fun in that.

Half the fun is the challenge of getting your ideas to come to life.
Your tips will help me on my way. Cheers

 

[Roff]

A shift register will work. You just have to start out with it cleared, then every X seconds (minutes, whatever), you shift in a "1". When it fills up, stop clocking it for 5 minutes, then clear it and start all over. The LM3914 might be a problem, depending on how much time the entire cycle takes, due to limits on capacitor leakage time constants.

 

[mister_e]

Maybe because i mostely work with those black-pinned box now but it's kinda perfect situation to use a Microcontroller. If you don't have the according stuff and time to spend on the 'how they work' stage, sure the above suggestion are interesting

Sometime i really think i lost the fundamental of electronic.. too bad, PICs or else microcontroller are just too fun!

 

[Paul Obrien]

Maybe a decade counter like this **broken link removed**

 

[HarveyH42]

We just got some new lighting in the warehouse I work at. The replaced the old high-pressure sodium, with some motion sensing tube-type fixtures. The lights are over 30 feet up, but light just before you pass underneath (even walking), stay on for about a minute or so if no further activity in the isle.

Your lighted path project sounded pretty cool. I think I would find a LM3914 bar/dot display driver and use a 555 for a ramp generator. You will have 10 outputs, in bar mode the outputs will stay on. To drive the 4W lights, you'll need FETs or something similar. Should work for under $20. You can make a triangle generator with an opamp instead of the ramp, and the lights will turn off in reverse...

 

[Hayato]

Maybe a decade counter like this **broken link removed**

Great Idea.

 

[HarveyH42]

Maybe a decade counter like this **broken link removed**

Basic sequencer... You guys forgot that only one ouput is turned on at a time, they don't latch on...

Just noticed that I some how got a promotion to 'Expert' and 'Senior Memeber'. I don't know where these titles come from, but I don't consider myself anything more then a hobbist. I learn what I need to complete projects or ideas. I've still got aleast 20 years left before being considered a senior, and start getting all those great discounts...

 

[Hayato]

Basic sequencer... You guys forgot that only one ouput is turned on at a time, they don't latch on...

Just noticed that I some how got a promotion to 'Expert' and 'Senior Memeber'. I don't know where these titles come from, but I don't consider myself anything more then a hobbist. I learn what I need to complete projects or ideas. I've still got aleast 20 years left before being considered a senior, and start getting all those great discounts...

No problem on that. Just hook the lamps in parallel, 2 by 2.

 

[Hayato]

Take a look at the attached image.

 

[Roff]

Basic sequencer... You guys forgot that only one ouput is turned on at a time, they don't latch on...

You're right, the centerline lights emulate a ball of light, traveling at high speed. If this is the case, a couple of 555s and a CD4017 seems to me like the simplest solution.

Henners wrote:

What i'm after is a runway light effect so they come on one (or in my case two) at a time but all stay on for the allocated time.

This sounds to me like each one stays on after it comes on.

 

[HarveyH42]

The title to this thread... '20 lights latching two at a time'. Guess I mis-understood what he meant. I thought he wanted the path to slowly light up, and stay lit for a while, before turning off again.

 

[Hayato]

The title to this thread... '20 lights latching two at a time'. Guess I mis-understood what he meant. I thought he wanted the path to slowly light up, and stay lit for a while, before turning off again.

So I mis-understood as well.

Henners, which one is the most similar to your idea? #1 or #2?

#1:


#2:

 

[HarveyH42]

Great visual! The #2 was what I thought we were talking about. But to get it with a 4017, you would need flip-flops or something for latching on. My preference is to keep part counts low, IC mainly. Etching and drilling a PCB is so much easier that way. One of these days I'll get around to building a jig for the drill press for doing ICs easier.

 

[mister_e]

if you really want to reduce IC to a minimum, you should use a microcontroller (PIC). Some of the have the internal osc, so no external one is needed. This project could be done with a single chip and few resistors. Now we talking about something easy to drill and etch.

Just a suggestion. But i do understand that it will take much of your time to learn them... so it's up to you.

I'm just adict of those beauty's

 

[Hayato]

Well,
I think these crazy circuits are going to work.

The #1 circuit is gonna work like the last post #1 gif;

The #2 circuit is special, it can work 2 ways:
1 - It's gonna work like the last post #2 gif
2 - Depending on 4017's VDD, it will simulate a ball of light travelling, like Ron said. Thank to the diodes voltage loss.
According to the datasheet, the IC's Voh (Voltage at high output) is Vdd - 0.5, so each darlington pair needs about 1.2V (or higher) to saturate, each diode the voltage decay about 0.7V, if you are able to manipulate the the IC's Vdd or the Voh's, you are able to accomplish.

 

[Henners]

Wow!!! i'm suprised at the amount of replies i've had to my project. Thank you all for taking the time to submit your help and ideas.

The title to this thread... '20 lights latching two at a time'. Guess I mis-understood what he meant. I thought he wanted the path to slowly light up, and stay lit for a while, before turning off again.

Hello Harvey yes this is the effect i am after.

Hi Hayato thanks for the circuit ideas
Sorry but the images are static on my computer.
I"ve only run one row of lights.
My (revised) idea is to have 1+20 come on, about 0.5 Secs later 2+19 also come on then 3+ 18 and so on until they are all lit. Stay on for 5 mins then all turn off.
The idea is for the path to light up at your feet then carry on lighting into the distance. If i had gone with my first idea (1+11, 2+12 etc) you would have had to be at the right end or the lights would come on from the distance running up to your feet, or design it to run in reverse order when initialised from each end
As the path meanders through native bush no one will see it running from each end to the middle

As a bit of overkill. From a job i've just finished, left over were a pair of safety beams which i've set up at each end of the path so it now lights up automatically when someone walks through them.
Unfortunately, they all come on at the same time at the moment as I've run out of cores in the cabling. Until i instal new wiring to cater for the staggered effect.

Hope this clears up the effect i'm after.
When I've finished the project am i allowed to load a video on this forum to show it in action?