flash LED newbie question

snipped-for-privacy@comcast.net skrev:

If you are up for a challenge, it can be solved with a PICAXE.

Its a microprocessor that can be programmed in a much easyier way than the C/assembly processors.

A 08M picaxe is about 3$ A download cable to program it, the same. The program will be a few simple lines, and you can reprogram the chip using just the programming cable (and 2 resistors).

It wont be 100% precise, but probaly enough for your use.

If you want to solve it without using a microprocessor, I think the timing will be the problem. The blink rate can be done with a 555timer, but the delay for

30-120minutes may be a problem to get precise.

If you want to try with the axe, I can make the program for you.

/Jan

What would be the bare minimum of parts to get started using a picaxe?

USB cable, software, some kind of prototyping (switch led) board? What would you recommend for a pic-08?

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default skrev: > What would be the bare minimum of parts to get started using a picaxe?

They have some pretty cheap (From 10GBP) starter sets with cable, board and a pic.

But if you want to buy the parts alone PICAXE 08(-M) Download cable (Can make it yourself, but its 3GBP, so...)

2 resistors (10K and 22K, 1/4W should be fine)

a solderlessboard or something to test on and some boardpins to make the connecter from the download cable.

if you only have usb, you will need a usb-2-serial converter.

their hp is

The 08 is cheap, but its pretty limited with memory, so only useful for small projects, it will hold about 40lines of basic.

I use 08-M for small projects, and 18X for more advanced projects. The "hello world" program is to flash a led, but that gets borring fast. For testing a solderless breadboard will do fine, so you can replace components.

/Jan

For simplicity, use a lamp timer like Intermatic TN111C Lamp & Appliance Timer ($6.49 at Amazon.Com). Plug a 5V DC regulated wall wart supply (CAT# DCTX-512 $3.50 at Allelcetronics.com) into it, and connect the supply to a blinking LED (CAT# LED-4 $0.90 for 2 at allelectronics) through a 100 ohm resistor.

------ -------- | |---| +|---[100R]---[LED]---+ |TN111C| |DCTX-512| | | |---| -|--------------------+ ------ --------

To operate, plug the timer in and set the ontime and off time buttons 30, 60 90 or 120 minutes apart. Then turn the timer dial until the LED starts to blink. It will blink for the duration you choose, then stop. It will repeat the next day and every day thereafter, unless you unplug it.

If you want a little more complexity, the TN111C can be replaced by a kit: QK152 $12.95 at

It requires a 12 volt power supply (CAT# PS-1251 $8.50 at allelectronics) and your circuit would change:

+---------------+ | | ------- | ---------- | | +|-+-| NC|--+ | 12V | | Qk152 | | Wall | | COM|---[1K]---+ | Wart | | | | | -|-+-| NO| [LED] ------- | ---------- | | | +-----------------------+

This will increase your cost, but you'll get a little more electronics experience assembling the kit and adjusting the timing, and it won't need to be unplugged to prevent it from turning on again the next day. Later on, once you have that working as you like, the 12V supply could be replaced with a DC-DC converter to allow operation from 3 volts or 1.5 volts. You would likely want to modify the Q152 as well to eliminate the relay which reduces current drain.

Ed

Here's one way:

I'd not build it till some of the experts here have checked it over, I think it'll work, but I could be making some silly mistake. .-------------------------------------------------------------. | This is an ascii schematic, if the diagram appears garbled | | try switching to a fixed-pitch font (courier works well) | | pasting it into notepad works well on ms-windows. | | or in google groups "view source" (found under options) | `-------------------------------------------------------------'

.----------[R4]-----------------+--- +3V | | | .--------------. | 30min | / | | | | | +---/ -->|---[ 1 \\_/ 16 ]---+--. | | | | 60min | / | | | +---/ -->|---[ 2 15 ] | | | | | 120min | / | | o | +---/ -->|---[ 3 14 ] |-| restart | | | o | | | | | | [ 4 13 ] | | | CD4060BC | | | | | | | [ 5 12 ]------+---[R5]---+- 0V | | | .---------. | | | | | | || | | [ 6 11 ]-+-[R2]--. +--||-' | | | | | || | | | | | c2 | [ 7 10 ]---[r1]--| | | | | | | | | | ||   | | | 0V ---[ 8 9 ]--+-||---' | | | | | || | | `--------------' | c1 | | | | LED | `--------|---||------------------' c2 1nF C1 1uF R1 2M R2 1M R3 820 R4 100K R5 100K Led some high-efficiency type. Other diodes 1N914 or 1N4148 for 90 minutes turn both 30 and 60 minute switches on. ( 150, 180, and 210 minutes can also be got using combinations of switches. ) Bye. Jasen

Thanks for the ideas.

This looks a lot more promising than the $20 stamps I've used.

I found a seller in the US that has them (08M) pretty reasonable ~$10 for three, ordered that, and a small board for prototyping that carries the serial jack, regulator, and socket for pic for $8, USB to serial cable $14, and the "Programming and Customizing the PICAXE Microcontroller" book for $21.

Has the stuff - the book I ordered via ABE books on line.

The 18X is only a little more money.

One question - is there any danger of inadvertently overwriting the boot strap loader or is that protected?

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default skrev:

As long as you use their program there shouldnt be a danger. Since the chips is regular PICs with a bootloader they can be programmed in a regular programmer, but then you risk overwriting the bootloader.

phanderson has a lot of other neat projects too :)

/Jan

default skrev:

By the way, check my post in the "Thanks" thread, theres a pretty nice simulator to catch to stupid mistakes before programming the pic.

although it cant debug much about inputs it can check the code and stuff.

/jan

Thanks again. Can't wait for the stuff to get here. Just got a confirmation that the book shipped.

I noticed in one blog that the author recommended running at 3 volts because it makes blowing an output line less likely. 3 V will make it handy for battery projects.

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should be R1 1M

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Bye.
   Jasen