Noob help

J

Jixz

New Member
Mmk.. im looking into making a blinker set for my bike using the picaxe to control it all. So im really confused on what i need to buy ( bare minimum ) to get started programing one of these baby's. I need two inputs and 9 outputs preferably ( 7 minimum ) and just need to know what i need to go out and buy to program this, and how to interface the picaxe with my computer. From what i can gather i need

1. Stereo PICAXE socket
2. Picaxe Usb cord.
3. Picaxe (probobly 18 pin)
4. and i think a protoboard would make it all a little easier.
 
U

Unit042

New Member
If you're just getting started with PICAXE, try going for "project board". The one I got comes as a solder together kit. Once you've soldred it, just plug it up and you're set to program! I went with one from sparkfun.com that programs the 8 pin version (cheapest kit). While it only programs 8-pin PICAXE's in the IC socket, you can take the serial in/out from the board and hook it up to larger PICAXE's.

For the DIY, look at the "PICAXE manuals", they contain what you're loking for. They should be at the picaxe.com site, under "reference" or something.

I went with a kit because I'm not that good with microcontrollers.

Now, with that out of the way, are you sure that a microcontroller is absolutely necessary(spl?)? Tell me more about what you want(ie: "I want X LED this to do that when that happens, and general PWM for everything"), and I might be able to figure out a cheaper method.
 
hippy

hippy

Ex-Staff (retired)
Left, right, dash indicator and perhaps an audible beeper but beyond those four I'm not sure what the other outputs woud be used for. Each side ( front and rear ) can be controlled by the same signal so that reduces the number of outputs.

If you detail what you're after in terms of functionality it'll make it easier to suggest what you may need. I'd suggest getting one or two 08M anyway so you can experiment with switching and controlling LED's and other outputs. Better to damage something inexpensive if that does happen and as that's unlikely if you don't do something silly they'll likely be of some use in future projects.

On top of what PICAXE you have as the heart of the sytsem you'll also need something to control the actual turn bulbs, realys, transisors and/or FET's. You'll also need a voltage regulator and other power supply components. Interfacing to any vehicle is a bit of a challenge.
 
B

BCJKiwi

Senior Member
If you really need an 18X and want to drive multiple LEDs or higher power output than the 10 or so mA the PICAXE port is OK for suggest the CHI035 High Power Board.

This is fully made up, comes with everything except the download cable and power supply. Includes the 18X, 8 inputs, 4 low power outputs and 4 High power (FET) outputs.

Hook up you power supply, download cable, inputs and outputs and you are in business - that is, once you have the program up and running!
 
J

jpyle1

New Member
Picaxe 08 proto board

If you will start with an 08M and the Picaxe Proto board, or similar, from SparkFun or other suppliers you can use the 08 board to also program the 14M and the 20M. This will give you a bit of extra capability without having to spend extra money, if you so choose. Just make sure the pin 1 position is correct on each type.

JP
 
J

Jixz

New Member
ok, after asking around a bit more i think im just going to do something like this :

http://img258.imageshack.us/img258/9514/rightflashir8.gif

so id only really need 3 outputs... but how would i go about getting the right voltages to the leds.. like said above 10 ma isnt near enough to power a 7 LED array..

Is there some sort of electronic switch i could use .. and just have the picaxe flip the switch?
 
D

Dippy

Moderator
For driving the LEDs have a look in the Manual 3 Interfacing Cicuits.
(Top-ish of the Forum , in the orange heading, click on the 'PICAXE Manual' dropdown thing and select Manual 3).

Look at how a transistor is used for the 'Signal Lamp'. Replace the bulb with an LED+Resistor. Several paralleled LED+Resistors can be easily controlled by a single transistor. (This is something the manual should include under the LED section).

For outdoor use you'll need some really bright ones.

When selecting a transistor choose one which can easily handle the calculated current.
 
W

westaust55

Moderator
Transistor to drive multiple LED's

In line with what Dippy has mentioned about using a transistor,
attached is a schemnatic that I have presented previously. This shows some data for basic 20mA LED's and higher intensity LED's

With multiple LED's, use one resistor for each LED.

While the BC558 indicated as one transistor type is rated at 100mA, I would not use more than 5 or 6 LED's at 12mA each.
Better to use the BD139 rated for 1 amp.
 

Attachments

J

Jixz

New Member
X_X you guys lost me.. Ive never used a transistor. From what i can gather they multiply the current given in the collector by the base to produce the emitter? ugh.. idk . help? :confused:
 
W

westaust55

Moderator
Jixz,

Yes a transistor has current amplification known as gain (abbrev Hfe).
The gain varies depending on transistor type and can range from as little as 20 to say 1000. A BC558 has a gain ranging from 200 to 800 whereas (from memory the BD139 has a gain of about 100.

The collector current = base current x Hfe
The emitter current = collector current + base current.

Until you are familiar with transistors, you will need to look at a datasheet for the transistor you select to verify the coenctions.
 
D

Dippy

Moderator
When you use a transistor as a switch you drive it into 'saturation'. i.e. give the base a good healthy bias. Amplifiers, where you use the Hfe, are a different matter.

i.e. LIKE I said before look at the switchy-onny light bulb circuit in the Manual 3.
And like I said before, "Replace the bulb with an LED+Resistor".

I really suggest you do a bit of reading about transistors if you really want to learn.

There must be thousands of websites describing transistors and there are also things called books which give good info.

Here's just one site which gives a few basics and examples:
http://www.kpsec.freeuk.com/trancirc.htm

Like someone said, Keep it Simple to start with.

Remember, you can parallel-up //^ a number of LED+RES combos and run it though a transistor. Examples usually just show a single LED+RES for simplicity.

Did you want someone to draw out a complete circuit ('schematic') diagram for you?
 
E

eclectic

Moderator
Unit.
May I make a couple of suggestions?
(That's Oldie Brit-speak for "I will anyway").

1. There is no need to use Photobucket or any other external agency.
Just use the "Manage Attachments" option, to attach sub-Megabyte size files.

2. In a previous post, Dippy made reference to the excellent kpsec site.
After you have looked at that link,
another useful reference, on the same site is

http://www.kpsec.freeuk.com/cdiags.htm

e.
 
W

westaust55

Moderator
The Manage Attachments feature can be accessed using:
1. The paperclip icon on the toolbar directly above the post text window, or
2. by scrolling down below the submit Reply button in the Additional Options area (usually not visible when you first start a post (even with 1000+ vertical pixel resolution on the screen)
 
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D

Dippy

Moderator
Unit, your schematic be clearer if you indicated that it is a PNP transistor for your 'high sided' switching. AND it would be more precise if you showed current out (direction) of the base as your signal.

Always best to use the proper symbols. A newbie wouldn't follow it at all.
Can you also provide some guidance on your suggested resistor values? That would be helpful to Jizz.

Could you also post an NPN version too as that would be a clearer comparison to the example circuits in the Manual 3 which no-one seems to bother reading.
 
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