How are you going to power leds and microcontroller board?
Do you have separate power supply/battery for leds?

 

How are you going to power leds and microcontroller board?
Do you have separate power supply/battery for leds?

Read the thread before asking a question.

 

That code looks good, exactly what I need.
If you can come up with the schematic for this (and a parts list) that would be very useful since its been a while since I have done anything with electronics (back then a Z80 or 6502 was state-of-the-art if you wanted to add a microprocessor to a project)
As for the LEDs, click on "specifications" and it shows the relavent data.
That lists a "typical forward voltage" of 2V, a "typical forward current" of 20mA and a "maximum forward current" of 50mA (among other things)

I’ll take a look tomorrow. The Stanley Cup Finals Game 6 is on. So far the good guys are leading. Two more periods to go.

 

you will need this: https://arduinodiy.wordpress.com/2012/05/02/using-mosfets-with-ttl-levels/ to switch strings on and off.

 

Any luck with the schematic? I am heading out to the location where a good electronics parts store is located in the next few days and it would be good to be able to pick up all the parts while I am in the area rather than having to go back there later...
Also is this circuit likely to be something that I can do on a breadboard rather than having to make a PCB for it?

 

Any luck with the schematic? I am heading out to the location where a good electronics parts store is located in the next few days and it would be good to be able to pick up all the parts while I am in the area rather than having to go back there later...
Also is this circuit likely to be something that I can do on a breadboard rather than having to make a PCB for it?

Hi! Got busy and to be honest, forgot what thread this was (probably due to age; I can walk into the bathroom and forget why I’m there). But I’m waiting for the cable guy and will have time this morning.

 

Thanks, hopefully I can find all the parts I need (including a means of programming the ATTiny85) locally and don't have to pay expensive shipping just to ensure I get what I need in time for when I need it

 

Here is the programmer I recommend.

https://www.sparkfun.com/products/11801

 

Annndddd...

Here is the schematic! Sorry it took so long.

 

Annndddd...

Here is the schematic! Sorry it took so long.
View attachment 179466

The top schematic is for one LED string. You’ll need to make four.

 

So I dont actually need a MOSFET to drive the LEDs with the ATTiny85 using the LEDs I have specified?
Also if I am powering this with AA batteries how many do I need? (and what, if any, other circuitry is required between the battery holder and the ATTiny85?)

As for the programmer, the problem with that specific item is that I can't find an Australian supplier for it and if I order it from Sparkfun directly the costs involved (cost of the product, cost of shipping, currency conversion/international card transaction fees, 10% Australian tax on top of all that and possibly more) it would be easier to just buy an Arduino Uno (or similar clone board) from a local supplier and some bits and follow something like https://create.arduino.cc/projecthub/arjun/programming-attiny85-with-arduino-uno-afb829 instead.

 

you will need this: https://arduinodiy.wordpress.com/2012/05/02/using-mosfets-with-ttl-levels/ to switch strings on and off.

By the way, no he doesn’t. Each string draws 20mA, within the capabilities of a pin. And he plans on only having one string illuminated at a time. Well within the total limit of the μP

 

So I dont actually need a MOSFET to drive the LEDs with the ATTiny85 using the LEDs I have specified?
Also if I am powering this with AA batteries how many do I need? (and what, if any, other circuitry is required between the battery holder and the ATTiny85?)

As for the programmer, the problem with that specific item is that I can't find an Australian supplier for it and if I order it from Sparkfun directly the costs involved (cost of the product, cost of shipping, currency conversion/international card transaction fees, 10% Australian tax on top of all that and possibly more) it would be easier to just buy an Arduino Uno (or similar clone board) from a local supplier and some bits and follow something like https://create.arduino.cc/projecthub/arjun/programming-attiny85-with-arduino-uno-afb829 instead.

Nope! No MOSFETs are needed. I checked your profile and you don’t have a location. Sorry about that. I’ll take a quick look for a programmer available in Australia...

 

Check Amazon Australia. They carry Sparkfun as a vendor. You may be able to get the programmer through them.

Search for “Sparkfun 11801”

 

I just realized the real-world lights I am replicating (I am building a scale model of a building with a famous light sequence on the roof and want that sequence in my model) have a different sequence to what I thought
The sequence goes
all off
1 on
1 2 on
1 2 3 on
1 2 3 4 on
all off
all on
start sequence over again

So if all 4 strings on at once would overtax the ATTiny85 then yes I will need MOSFET drivers (if so, schematics for that would be nice along with details of what sort of MOSFET to buy)

 

For reference what I am building is the famous XXXX building here in Brisbane and the plan is to have one LED at each corner of the X with one string of 4 for each X on the sign. (I already have Xs ready to accept the LEDs I picked as well as the rest of the building)

 

First, nope! The ATTiny85 can source enough current for all of your LEDs. It has a maximum of 200mA; you need 80...

You can confirm that at this link.

You’re still good.

 

For reference what I am building is the famous XXXX building here in Brisbane and the plan is to have one LED at each corner of the X with one string of 4 for each X on the sign. (I already have Xs ready to accept the LEDs I picked as well as the rest of the building)

That will look nice.

As far as power, I’d use 4 AA batteries, with a 1A diode in the positive line before going into the μP (ATTiny85). Wire the diode inline (anode to +6V) and measure the voltage from the diode cathode to the batteries ground (negative). You should read about 5.3V

 

If you are running leds from pin, sourcing from I/O pin thru string to ground,
and UP Vdd of 5V, your calculation looks like -

Rled =[ 5V - ( 2.1V + 2.1V)] / .01 A = .8 /.01 = 80 ohms.

Just an FYI, many processors drive to ground better than source out of
a pin. So "normally" you would tie R's to Vdd and connect LED cathode to
pin. This case, the ATTINY85, has symmetrical drive capability, so you
can source the current out of the high side P MOSFET in the GPIO pin.


Regards, Dana.

 

Note these conditions have to be met for GPIO total current -

4. Although each I/O port can sink more than the test conditions (10 mA at VCC = 5V, 5 mA at VCC = 3V) under steady state
conditions (non-transient), the following must be observed:
1] The sum of all IOL, for all ports, should not exceed 60 mA.
If IOL exceeds the test condition, VOL may exceed the related specification. Pins are not guaranteed to sink current greater
than the listed test condition.
5. Although each I/O port can source more than the test conditions (10 mA at VCC = 5V, 5 mA at VCC = 3V) under steady state
conditions (non-transient), the following must be observed:
1] The sum of all IOH, for all ports, should not exceed 60 mA.
If IOH exceeds the test condition, VOH may exceed the related specification. Pins are not guaranteed to source current
greater than the listed test condition.

Regards, Dana.