help with project with map & LED's

Forget f-fs. Use a microcontroller or somesuch. Check out

There are lots of other choices, too!

I'm too lazy to draw this, but visualize an 8-input NAND gate, and 8 pushbuttons with one contact grounded and the other pulled up to +5V with, say, s 4.7K resistor. Each of the switches' active side goes to one of the inputs of the NAND. Normally, they're all high (because of the pullups) so the output of the NAND is low.

Now, take 8 ea. R-S flip-flops. Run a wire from the active pole of each switch to the S input of each (active low, say, 7474 or so), and take the output of the 8-input NAND, invert it, differentiate it so you get a pulse, and send that low-going pulse to all of the R inputs of the flip-flops.

When you push the button, the output of the NAND switches, that gets inverted and resets all of the flip-flops. Because of the capacitor, that goes away, but your finger is still on the button, grounding the S input of the flip-flop you wanted. It will only be in its indeterminate state for the time of the "Reset" pulse.

Hope This Helps! Rich

you could do this with RS latches where each output of a latch (set when you press the button) goes to the reset of each other latch via a diode... but... why break your back - you could do this with about

20 lines of code in a $4 micro-controller and only a single chip

Is there only one mineral lode per mine? If not, then diode OR the lamp drive. As for the input switching, you can use an octal latch like the

74HC373, and a switch debounce one-shot like the 555. View in a fixed-width font such as Courier.

. . '373 . -+- +-------------+ . .--o o----------------------+--|D1 Q1 |->

. | | | | . | -+- | | | . +--o o-------------------+--|--|D2 Q2 |->

. | | | | | . | -+- | | | | . +--o o----------------+--|--|--|D3 Q3 |->

. | | | | | | . | -+- | | | | | . +--o o-------------+--|--|--|--|D4 Q4 |->

. | | | | | | | . | -+- | | | | | | . +--o o----------+--|--|--|--|--|D5 Q5 |->

. | | | | | | | | . | -+- | | | | | | | . +--o o-------+--|--|--|--|--|--|D6 Q6 |->

. +5V | | | | | | | | | . | | -+- | | | | | | | | . +-R--. +--o o----+--|--|--|--|--|--|--|D7 Q7 |->

. | | | | | | | | | | | | . >| | | -+- | | | | | | | | | . |--+-+--o o-+--|--|--|--|--|--|--|--|D8 Q8 |->

. /| | | | | | | | | | | . | R R R R R R R R | G | . | | | | | | | | | +-------------+ . | R=10K +--+--+--+--+--+--+--' | . | | | . | --- | . | GND +5V | . | | 555 | . +-------R-------. +-----------+ | . | | | V+/RST | | . | 0.1U | | | | . +------||-------+-------------|THRESH | | . | | | OUT|----+ . |o EXT R 1U | | | . -| RST | + | | | . |o +----||---+---|TRIG | | . | | | | | | . +5V --- | +-----------+ | . GND | | . | | . '-----+--[47K]--+----' . | | . '---|

This will work much better, slight polarity problem on the latch enable of the previous: View in a fixed-width font such as Courier.

. . +5V '373 . | -+- +-------------+ . +--o o----------------------+--|D1 Q1 |->

. | | | | . | -+- | | | . +--o o-------------------+--|--|D2 Q2 |->

. | | | | | . | -+- | | | | . +--o o----------------+--|--|--|D3 Q3 |->

. | | | | | | . | -+- | | | | | . +--o o-------------+--|--|--|--|D4 Q4 |->

. | | | | | | | . | -+- | | | | | | . +--o o----------+--|--|--|--|--|D5 Q5 |->

. | | | | | | | | . | -+- | | | | | | | . +--o o-------+--|--|--|--|--|--|D6 Q6 |->

. | | | | | | | | | . | -+- | | | | | | | | . +--o o----+--|--|--|--|--|--|--|D7 Q7 |->

. | | | | | | | | | | . | -+- | | | | | | | | | . +--o o-+--|--|--|--|--|--|--|--|D8 Q8 |->

. | | | | | | | | | | . R R R R R R R R | G | . .-----------. | | | | | | | | +-------------+ . | | | | | | | | | | | . | \\| | | | | | | | | | . | 2n3904 |-+--+--+--+--+--+--+--' | . |

This may be a little more complicated if some of the mines have more than one mineral, so that its LED will be lit for two or more different input buttons. There is also the question of what is the best way to light a large number of LEDs efficiently.

The first problem can be solved by a wired OR circuit consisting of diodes from the LED to the logic output. This will work fine if each LED has its own limiting resistor, but if you need to light 30 LEDs at 20 mA each that would be 600 mA and a total of 3 watts for a 5 VDC supply. This would require a small power transistor or MOSFET. It will be more efficient to drive several LEDs in series, but then that set would need to have the same range of minerals.

Paul

Sounds like a possibility. I know not much about digital electronics, but some of the basic concepts I know. (Never got beyound the SN74-series in jy time, and then decided that there were other interests to persue...)

Thanks for the idea.

Ronald

"Rich Grise" skrev i meld>

The microcontroller-solution is definitely the most attractive, but for someone like me it will be a long learning-curve. If I find someone willing to help, it would be fine. I can just about tackle a bit of digital electronics, and your idea with latch/reset by diode is similar ot one of the other replies, and withing my technical skils.

Thanks!

Ronald

skrev i meld>

This is very nice indeed.

Of course, there are numerous combinations possible. When the quartz-button is pushed, maybe 150 LED's will light up, feltspar basically all LED's will light up, but when the uranium button is activated only one will have to light up.

I will get hold of the 373-datasheet and study your idea carefully. The schematics was very good readable with courier.

You happen to know if the number of buttons can be increased to let's say 10 or 12? I will then need 2x 373?

Thanks for your reply!

Ronald

"Fred Bloggs" skrev i melding news: snipped-for-privacy@nospam.com...

Indeed, many of the mines have more than one mineral. Most of them have feldspar, very many have in addition quartz, while the other minerals are more rare, but basically always are found in a mine where either quartz or feldpsar have been mined.

The power requirements are the least of my trouble. I will gladly build a

50-100 W power supply, that's the kind of electronics I am familiar with.

My problem is that I feel very uncertain about the digital electronics.

The suggestions to use a microcontroller are of course well-intended, but that wouldn't help me much if I couldn't get additional help programming the chip.

Thanks for your reply!

Ronald

"Paul E. Schoen" skrev i melding news:452d1303$0$25796$ snipped-for-privacy@news.coretel.net...

But that will require prior knowledge of microcontrollers, I don't suppose I will find a ready to use solution. That means programming...

Then I will need REEL help!

But anyway, it's a path I might pursue if I find someone willing to help me (against a reasonable fee).

Ronald

"Charles Schuler" skrev i melding news:9PSdnWcBOrLcgLHYnZ2dnUVZ snipped-for-privacy@comcast.com...

You might do better with a computer you CAN program. In the US I would look for an old Color Computer or Model 100 and interface to that.

You might check the above because it has links to a multitude of sources, some of which include code.

Sure, you can pay for coding, but you might find that something out there in the public domain is close enough to what you need so that you could easily modify the coding yourself.

I used to do some of this but am now tired and retired.

Why not just use push buttons which switch off when you lift your finger? That way you can look at more than one mineral at once. Push the buttons in pairs and you might just be surprised at the mineral associations which come to light.

R

You can do this with SCR's - one for each mineral:

+12 -----+------------------+---------+---{{{-----+ | | | | | [LED] [LED] [LED] | | | | | [1K] [1K] [1K] | | | | | Pb1 [SCR1 [SCR2] [SCR8] | ___ /| /| /| +---o o---[330]--+ +---------+---{{{-----+---+ | | | | | | +--->|---------+ | | | | D1 | | | | | Pb2 | | | | | ___ | | | | +---o o---[330]------------+ | | | | | | | | +--->|---------+ | | | D2 | | | {{{ {{{ {{{ {{{ | | | | | Pb8 | | | | ___ | | | +---o o---[330]------------------------+ o | | + | +--->|---------+---[C1]----+----+ .->| N/C D8 | | | | +---[3.3K]--+ [RY1] o | | Gnd -------------------------------------------+---+

How it works: pressing any pusbutton biases the respective SCR gate to turn on, and energizes the relay briefly through C1, a 100 uF capacitor, as C1 charges. This opens the ground path to all the SCR's (via the normally closed contact of the relay), turning off any previously on SCR. The 3.3K resistor discharges C1 between button presses.

As soon as the relay drops, the SCR corresponding to the button being pressed turns on. The diodes prevent any other SCR from turning on. The LEDs connected to the SCR turn on and stay on until the next time a button is pressed. Each LED you connect to the SCR needs its own current limiting resistor. If you use red LEDs, 1K will limit the current to ~10 mA - for brighter you could use a 470 ohm resistor instead of the 1K. The C106D SCR works nicely. It is capable of 4 amps, so it can light a LOT of LEDS. You may need to experiment with the value of C1, depending on what relay you use. It affects the timing of how long you need to press a button to turn the SCR on.

If some mines contain more than 1 mineral, they can be wired to multiple SCRs through diodes. Small signal diodes like 1N4148s will be fine for that purpose. 1N4001's should be used for the diodes connected to the pushbuttons.

Ed

I'm assuming each mine could have a combination of these minerals. This really sounds like a job for a uP. Note a display driver like the Max7219 can be used "memory mapped" rather than just for 7 segment displays. One chip drives 64 leds, so you will need 5 chips. The chips can be hooked up in series, so 3 wires will be all that is required to feed the data.

One thing you could try, and I suspect I'll be dissed for making this suggestion, is to write a program that "bit bangs" the parallel port to make it look like a serial port. The you can do all the programming on a PC rather than try to fiddle with controller chips.

While the Max7219 has a noop, I'd suggest setting up arrays in your program to mimic the leds, and just write the whole damn thing every time the data changes.

I see, I see, clever. Simple but clever

But are you sure if I hook up 200 LED's (in case of feldspar which has been mined in almost all of the mines) to one SCR it will hold? The C106D is rated for 4A, whereas 200 x 0,10 mA =20A. Shouldn't I use one with much higher amperage?

The idea is worth trying, a test wouldn't cost me much, apart from the SCR's I would have to buy, don't have so many in stock.

Let me know if I am wrong about the capacity of the SCR!

Thanks!

Ronald

"ehsjr" skrev i meld>> Sounds like a possibility. I know not much about digital electronics, but

On 12/10/2006 the venerable Ronald etched in runes:

Er no. 200 LED's at 10mA per LED is 2A.

If you are using a power supply of 12V for example you can connect four LED's in series with a smaller ballast resistor. So 200 LED's comes down to 50 chains of four at only 500mA in total.

--
John B

On 11/10/2006 the venerable Ronald etched in runes:

Hi Ronald,

Where are you? I've done exactly this for a local museum, send me an email off list and I'm sure I'll be able to help.

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John B