I don't know a lot yet about electronic components but I fear no such thing so I decided that since I started playing with arduino I should learn to create my own arduino boards.
Hence I was trying to gather all the parts from the well known breadboard tutorial at mouser.com
My lack of knowledge is now putting me in the situation that I don't know what to look for on parts that look so generic yet it turns out thers hundreds of variants of them.
It's obvious what IC goes on the board but to me it's far less obvious if I'm choosing the right capacitors etc.
I was hoping someone here could help me along.
I'm trying to order parts for 10 arduino DIY kits and the things I'm wondering about are the capacitors but I really started to doubt the simplest thins such as leds and resistors because there's just so many of them.
If someone can have a look at it and let me know if I'm on the right track, that would be great!
Thanks in advance....
Thru hole or surface mount?
Thru hole, sort Rs, Cs, Ds for radial lead.
Resistors - 1/8W & 1/4W are plenty, just sort for low cost.
ceramic Caps - 22pF, 25V, sort for low cost. 50V would be okay too, might be a little bigger.
ceramil Caps 100nF/0.1uF, 25V, sort for low cost. 50V would be okay too.
16 MHz crystal - HC49S package, sort for low cost.
LEDs - pick a color, sort for low cost, then higher brightness if you want. Not really needed tho, just becomes obnoxious to look at after a while. 3mm or 5mm. 1K current limit resistor will limit current to a couple of milliamps.
Voltage regulator? 7805 are good for 1A. Hard to go wrong with TO220 package.
Need 3.3V regulator too? Search for LDO parts that can be powered from 5V.
aluminum electrolytic 10uF & 1uF caps for regulator, 16V, radial can
Reverse polarity diode. 1N4148 or 1N4158 are good, sort for 1A of current capability.
Anything else?
I normally power 5V circuits from 5V switching regulator wallwart and don't bother with 7805 regulator. If more voltage needed, like 12V for LED strings, I'll put in a 7805 just to power the '328.
Need USB interface? Add MIKROE483 from mouser for FTDI module.
End result of parts will look something like this for a board like this:
that's lookin' real good 8)
I was planning on using these parts for projects that require a different form factor since arduino compatible boards are so cheap nowadays that building my own is not cost effective.
cjdelphi:
I like to find out what I want to build then source the parts., rather than buying a handful of everything.
which sounds quite logical
But as I stated earlier, I'm stille learning so I need some stuff to play with. Some of these parts (espacially the 328 itself) drop in price seriously when ordering in multiples of 10 and there's not shipping cost at mouser when your order is for a certain value.
Taking those factors into account, I decided to "buy a handful of everything" as you describe it.
I'll be ordering some other parts as well; I/O multiplexers/demultiplexers, some common stuff.
When reading through all kinds of online resources / projects for inspiration I foresee to use most (if not all) of these components in projects for which the ideas are starting to form in the back of my head.
cjdelphi:
I know this much I'll still be learning the day before I die... last day off lol
Hahaha... lol!
The good thing is you get a day off at least...
Anyway, I'm in a different stage of the learning curve then a lot of people on this forum is more what I meant.
(Although, judging by all the posts and whole topics about ESD packaging being conductive I guess a lot of people are still in a relatively early stage of the learning curve )
cjdelphi:
I like to find out what I want to build then source the parts., rather than buying a handful of everything.
Some things, like resistors, caps, common transistors and diodes, 5mm LEDs, header pins, perfboard, etc I like to have piles on hand so I don't have to wait for shipping to start a project that occurs to me out of the blue.
However this can be cost prohibitive for the more esoteric parts, so for most other things I order as-needed.
I think I'm going to add a pile of 28-DIP Atmega328's to my stock though. I keep thinking of new things to do with them.
100nF ceramic caps - put one on each of these pins: VCC, AVCC, AREF, and you will need one for DTR.
10uF/1uF - put the 10uF on the input to the regulator, put the 1uF on the output of the regulator.
2 Diodes:
1 in series with positive voltage going to the regulaor, just in case you connect up power backwards.
1 in parallel with 10K pullup resistor on Reset pin; anode to Reset pin, cathode to +5.
This will dissipate any spikes on the reset pin to +5 and prevent the chip from launching into high voltage programming mode (and appearing as if hung, especially after a reset button is pushed and sometimes after a software generated reset on DTR).
I'm also one of those that likes to have a healthy surplus of parts. It's still kinda rare, but every now and then I have everything I need in my personal inventory to build some little project. The downside to buying what you need on-demand is that, if you ever realize that 22k resistor should've been a 33k resistor, then you're waiting on shipping or taking a trip to Radio Shack to buy them at $1.50 apiece or whatever.
SirNickity:
I'm also one of those that likes to have a healthy surplus of parts. It's still kinda rare, but every now and then I have everything I need in my personal inventory to build some little project. The downside to buying what you need on-demand is that, if you ever realize that 22k resistor should've been a 33k resistor, then you're waiting on shipping or taking a trip to Radio Shack to buy them at $1.50 apiece or whatever.
How about rolling your own? ... Nichrome wire (if you're desperate) will give you a resistor you require for short term.
CrossRoads:
100nF ceramic caps - put one on each of these pins: VCC, AVCC, AREF, and you will need one for DTR.
10uF/1uF - put the 10uF on the input to the regulator, put the 1uF on the output of the regulator.
2 Diodes:
1 in series with positive voltage going to the regulaor, just in case you connect up power backwards.
1 in parallel with 10K pullup resistor on Reset pin; anode to Reset pin, cathode to +5.
This will dissipate any spikes on the reset pin to +5 and prevent the chip from launching into high voltage programming mode (and appearing as if hung, especially after a reset button is pushed and sometimes after a software generated reset on DTR).
Thanks!
There's quite a lot of 'duino makers on the web that show circuits with minimal parts but I guess most do not take those unwanted situations you describe into account.
I think it is good to realize that many "instructions" on the web are created by those with not much more knowledge than yours... and for some reason, they like to omit things like capacitors and resistors because they don't "understand" them.
It's human nature to think "well it works without it... so it must be OK" and then not realize your design is suffering.
It's sort of like the "Hey, if I don't get caught, it's not illegal" kind of logic. There is a flaw in the somewhere... it will bite you.
pwillard:
It's human nature to think "well it works without it... so it must be OK" and then not realize your design is suffering.
It's sort of like the "Hey, if I don't get caught, it's not illegal" kind of logic. There is a flaw in the somewhere... it will bite you.
Strangely, this goes not only for electronics, but for every job (i was thinking software engineering first). I try to explain my students, but it takes so e experience to see why.
pwillard:
and for some reason, they like to omit things like capacitors and resistors because they don't "understand" them.
Guilty as charged. I was always annoyed with all the caps and resistors real EEs seemed to scatter across their PCBs. But as I learn more, I must grudgingly admit all those "excess" components really do belong there.
For example, I had my LCD working via a shift register and the SRLCD library, until I used a new power supply with a slightly different voltage and then all I got on my display was garbage. After pulling my hair out for a day or two, I finally realized the diode I was using had too much internal capacitance. So, diodes are NOT all created equal and those little details DO matter.
cjdelphi:
Do you mean the diode had a lower voltage drop thus brighter the display? Or dimmer?
The diode in a 2-wire unlatched SRLCD acts as a logic AND gate to reduce the pin count on the Arduino. With a 4.6V power supply, the digital signal produced was just barely clean / fast enough for the LCD to decode, but at 5.1V the 1N4001's capacitance dirtied / slowed down the edges (at least, I assume, since I have no 'scope) enough to mess things up.
In retrospect, it was amazing the 1N4001 worked at all.
so I decided that since I started playing with arduino I should learn to create my own arduino boards.
)
