I’m moving from an UNO to a breadboard in hopes of using eagle software to create a prototype. I followed the tutorial on aurduino.cc and I have successfully built a working breadboard arduino. It is however, missing a 3.3V power source and I have 2 I2C sensors which need 3.3v. I’ve seen from my work with Xbees that sparkfun and adafruit have used capacitors and resistors to create a 3.3V power source. Should I rework my breadboard to add a 3.3V voltage regulator and have a 3.3V source in parallel to the 5V source, or is there an easier way with 100uf capacitors, etc.
I’m a software programmer and I’m learning hardware, so I’ll need a complete solutions like connect a 3.3V voltage reg and x resistors and y capacitors etc.
Thanks in advance,
Bill
Use a 3.3V regulator. The data sheet will have details of the capacitors.
If you’re looking for a 3.3v power source, grab an old PC ATX power supply, if it has a rocker switch to turn it on/off then short the green wire to a black wire. If it doesn’t have a rocker switch, go to radio shack and put an on/off (single) switch between the green and black wires (switching on turns on power supply).
After that the orange wires are 3.3v (I think there are at least two 3.3v) Reds are 5.5… the efficieny is pretty good. If you need something mobile, get a 6v battery with a potentiometer attached, using a multimeter turn the potentiometer until it’s at your desired voltage.
Hi Bill,
for a simple and “complete” solution try Sparkfun’s LiPower - Boost Converter sku: PRT-10255.
• Input voltage 0.3-5.5V
• Output voltage 3.3 or 5V “solder jumper selectable”
By the way, don’t stress about not using a Polymer Lithium Ion Battery as the power source - use your 5V supply instead.
As stated, “the board can also be used as a general purpose buck and boost regulator”. Yay!.
Note: “This board does not have reverse polarity protection, so please use the correct LiPo batteries (see related items below) or be sure to recognize the polarity if using your own input source.”
- in your case, be sure to connect up your 5V supply with the correct polarity!.
Also, to make life easy … pick up Sparkfun’s JST Jumper 2 Wire Assembly sku: PRT-09914 to easily connect the abovementioned unit to your 5V supply.
Please post a link here to your completed project if you write it up.
rblasik:
If you need something mobile, get a 6v battery with a potentiometer attached, using a multimeter turn the potentiometer until it’s at your desired voltage.
Don’t do this. Potentiometers adjust resistance, not voltage. If you have an absolutely constant current draw, ohm’s law says that you could use a pot to adjust current, but that is not so with sensors.
I would say to not bother with the buck/boost converter (the liPo one mentioned in the previous post), you could do with a simple linear regulator. Find one rated for 3.3V, and make sure the “dropout voltage” is less than 5-3.3=1.7V if you have a 5V source. Alternatively, just connect it to your input voltage (9V or whatever) and don’t worry about the dropout voltage.
WizenedEE:
I would say to not bother with the buck/boost converter (the liPo one mentioned in the previous post), you could do with a simple linear regulator. Find one rated for 3.3V, and make sure the “dropout voltage” is less than 5-3.3=1.7V if you have a 5V source. Alternatively, just connect it to your input voltage (9V or whatever) and don’t worry about the dropout voltage.
Remember that Bill said this:
kelly7552:
I’m a software programmer and I’m learning hardware
I'm presenting him with a very simple solution so he's not stuck.