View Full Version : Giving info on components that seem to work nice

06-30-2013, 11:56 AM
This is just to help other guys that might be looking for components for their projects. I am still in early days of using these items, but things seem to be going well

http://www.hobbyking.com/hobbyking/store/__16575__A123_3_3VB_Lithium_Ion_2300mAh_Single_Cel l_Battery.html
I have 2 in series giving me just over 6.7V after fully charged. They don't have the extremely high charged voltage as other batteries like NiMh. Seems these batteries can be discharged down to 2V each so 4V total, but lower when pulsed. This is on the manufacturer documentation included with the battery. There is alot of discussion around these batteries. The manufacturer recommends to charge them as LifePo4 so I will assume they are LifePo4

Voltage regulator
http://australia.rs-online.com/web/p/low-dropout-voltage-regulators/0254557/?searchTerm=MIC29152BT&relevancy-data=636F3D3226696E3D4931384E4B6E6F776E41734D504E2 66C753D656E266D6D3D6D61746368616C6C7061727469616C2 6706D3D5E5B5C772D5C2E2F252C5D2B2426706F3D313326736 E3D592673743D4D414E5F504152545F4E554D4245522675737 43D4D4943323931353242542677633D424F544826
This regulator is the best low drop out regulator I could find. There is one from Microchip that is about the same, but that one can't handle the high voltage that this one can as input. I think the Microchip one had a max of 6V input. I reduce my 6.7V down to 3.9V to drive the Teensy 3 directly. If my calculations are right I should be able to get the batteries down to 4.2V before the regulator will stop working. It has the highest Amp possible with the lowest drop out. There are bigger versions that can go to 3A and I think even 5A. I am using 232k and 110k 0.1% resistors to "program" it. I also have 2 diodes in series as a third output to get the voltage down to 3.2V. So my circuit has 3 voltage outputs for the different parts that I need to run. 6.7V for my voltage test circuit to determine current battery level, 3.9V for the Teensy 3, sound card, high power IR LED and 3.2V for buttons or other low amp things like low amp LEDs

This sound module works with a 4GB Sandisk SD card. Most of these kinds of modules seem to have difficulty working with different SD cards. I haven't been able to test other cards. The module is extremely easy to work with. Plug the 2 speaker wires into the module and send serial commands to the module. It draws 30mA constantly about. Still working on better ways of using it. The manufacturer is also very good. Mr Li at Waytronic normally reply to me in 48 hours of any question

06-30-2013, 06:24 PM
Battery: I have one of these. Handy for many things. Can also run Teensy and most any USB powered device.
http://www.frys.com/product/7309724;jsessionid=KX2au-E95kR+Isi+uJrD+g__.node1?site=sr:SEARCH:MAIN_RSLT_ PG

07-01-2013, 01:38 AM
I'm in early days, too.

SparkFun Polymer Lithium Ion Battery - 850mAh, PRT-00341

It fits along with a Teensy 3 and headphone jack in an Altoids "smalls" tin, though just barely. The Teensy 3 stacks on top of the battery. With no power saving measures beyond setting the clock to 24MHz, I get a couple of days of battery life.

Voltage regulator
2950 CZ-3.3 812

I used a TO-92 package, though this might not be the ideal choice for heat dissipation.

Battery charger
Adafruit Micro Lipo - USB LiIon/LiPoly charger - v1, ID: 1304

I use this to charge the battery above. I didn't include the charger in this build. I unplug the battery from the Teensy to recharge it.