Show Posts
Pages: [1] 2 3 ... 18
1  Using Arduino / General Electronics / Re: Dual Power Supply on Arduino on: August 05, 2014, 12:52:50 pm
Fungus has it right.  when you connect any dual supply sub-system to the arduino, you ALWAYS connect the sub-system's negative output to the arduino's ground and use voltage dividers to drop the signal voltage levels to what the arduino can tollerate.  otherwise, you make'em big smoke.........
2  Using Arduino / Project Guidance / Re: help for flash gun code on: July 09, 2014, 01:27:47 pm
Google:  555 timer, One-shot, Monostable Multivibrator.
3  Using Arduino / General Electronics / Re: Help me find these connectors... on: July 08, 2014, 02:21:02 pm
Isn't the connector shown by the OP called a "JST"?  Three pin is a JST-3.

CPARKTX,
Go to the Goodwill store at 183 & New Hope (i think), But a couple of old VHS video players, or CD/DVD players and tear them apart.  Filled with lots of connectors and other goodies.......
4  Using Arduino / Project Guidance / Re: Hacking a SmartCard on: July 07, 2014, 01:42:35 pm
Google "SCR331" or "SCM SCR331"
5  Using Arduino / Project Guidance / Re: Using arduino as a repeater using NRF24 on: July 02, 2014, 09:32:46 am
Predicted, measured, absolute, distance between nodes is greater than reliable range of the individual nodes, hence the need for the 'bucket brigade' with the inserted repeater node.

Or spend more money and get nodes with greater ranges.

There are few problems, concievable by man, which cannot be resolved by sufficient application of force, be it mechanical, political (/military), and/or economic.  Brute force solution may not be ellegant, but it usually works.
6  Using Arduino / Project Guidance / Re: Using arduino as a repeater using NRF24 on: July 01, 2014, 01:59:52 pm
From your description of the requirements, you only need one NRF24 on the repeater station.  Timing shouldn't be an issue.
Start off with repeater in recv mode receiving and verifying packets from the  sender, and the end receiver in recev mode waiting for a message from the repeater's ID.
When repeater receives correct message from transmitter, it changes mode to transmit and resends the message to the end receiver's ID.
End receiver then receives and verifies message from repeater and commits to proper response.
reverse the process if the sender requires verification of the action.
7  Using Arduino / Project Guidance / Re: Variable Resistance Using Arduino to Convert Output Resistance on: June 26, 2014, 02:09:25 pm
Change out the sending unit in the tank.
8  Using Arduino / General Electronics / Re: 24V through a 1Kohm, 1W resistor; what is too hot? on: June 19, 2014, 02:30:03 pm
Pull up???  What's that got to do with current limit to the input side of the opto?
9  Using Arduino / General Electronics / Re: normal mosfet vs power mosfet? on: June 18, 2014, 11:02:27 am
Lefty,

Switching, small signal, and Power??
10  Using Arduino / General Electronics / Re: H Bridge on: June 11, 2014, 02:24:25 pm
Did you miss the part about removing power and coasting?
11  Using Arduino / Project Guidance / Re: Using an Arduino to Trigger Staging in Two Stage Model Rocket on: June 04, 2014, 02:33:47 pm
G force at take off is likely to be rather high. better get a few spare accelerometers. Too much G load will fracture the inards of one.
12  Using Arduino / Project Guidance / Re: Prop sound chip interface on: June 04, 2014, 02:18:07 pm
How do you ground a potato chip?
13  Using Arduino / General Electronics / Re: LM317 voltage regulator R2 is getting very hot? why? on: May 27, 2014, 01:41:00 pm
Good luck. we learn more by out mistakes.  Think about having another go at the data sheet. it is pretty explicit.
14  Using Arduino / General Electronics / Re: LM317 voltage regulator R2 is getting very hot? why? on: May 27, 2014, 01:32:54 pm
The 317 can also be configured as a current regulator (for relatively Constant Currents BELOW 1A). And,, you canconfigure one 317 as a voltage regulator (for desired Vout+1.25V) and follow it with a second 317 configured as a current limiter.  It works. It kills batteries. It wastes parts.  I've done it many times and with regret, will probablly continue to do so...
15  Using Arduino / General Electronics / Re: LM317 voltage regulator R2 is getting very hot? why? on: May 27, 2014, 01:18:51 pm
AMPs am CURRENT,,, It's Voltage , Resistance, and Current (in AMPs).
The 1.25 V and 50uV (not 5mV) are what is passed by the Adjust pin of the regulator. You can read the datasheet to find out how it works. But that current path is totally different from the reference loop setup by R1 and R2.  That sets the Highend voltage the regulator will pass.  with proper heat sinking, the 317 will pass a max of something like 1 AMP, as long as you source it with Vin=Vout+1.25V, or more and at least 1 AMP.
Pages: [1] 2 3 ... 18