My Wiring diagram for MagicPie/PAS/++

[gacrux]

When I build my e-bike I got too much wires, and I thought it looked awful.
I tried to understand all wirings, and redesiged a little.
I wanted the trottle light switch to turn Pedelec system on/off.
I wanted power for my lights (3V)
I wanted power for my GPS.

In my design I wanted to connect all wires through a veroboard.
The result is WiringMagicPie.pdf (attached)
BA03FP is a 3V regulator.

Everthing worked fine exept for the GPS. For some reason the Voltage from +5V is not stabilized so the GPS detects power on/off all the time. So I dropped the GPS.

Warning: You should have som experience with soldering before doing this.

[GM Brazil]

You can use a LM317 (if I'm not wrong about the name) variable voltage regulator with a high definition variable resistor for accurate voltage settings. The schematics for the simple setup use some capacitors too and is available in the datasheet of the component. Very simple! I'll produce this as a special battery cable to have a usb power output from the battery to charge gadgets, etc., and sell as an accessory to my clients here .

By the way, nice work!

[GM Brazil]

Like this in this photo attached

There is two circuit in that protoboard, one for +5v and the other for -5v. They are the same but a different regulator.

This is the voltage regulator I used for my experimental rocket motor testing data acquisition system. This regulates the voltage to the force sensors, it is a very simple and cheap circuit but very precise!

http://picasaweb.google.com.br/brunofporto/EletrNica#

[gacrux]

I'm not sure whats wrong with the 5V+. Since the the 5+V was not stable I used a 24V, 7805 regulator, and some capasitors (1000uF between 0V and 5V). It didn't help very much (in fact it was worse - turned on/off very rapidly). One day I will examine the 24V from the Lithsium battery with a oscoliscope. Until then I will feed the GPS with 1.5V batteries.

[GM Brazil]

The 7805 is not so precise, that is why I used the LM317. My results for +5v with the 7805 are not good, they change with temperature and type of capacitor used for example.

For your GPS if the voltage regulator drops too much the voltage it seems like a low battery condition.

[Bikemad]

I'm not sure whats wrong with the 5V+. Since the the 5+V was not stable I used a 24V, 7805 regulator, and some capasitors (1000uF between 0V and 5V).

The problem is you're expecting the Magic Pie's +5V to supply much more current than it is capable of doing. I found it could not even deliver 0.02A (20mA) and it was unable to switch a miniature 4.5V relay that I was hoping to use.

The LM317 might be able to supply enough current for your GPS as long as it requires less than 500mA, but it will definitely need a suitable heat sink to dissipate the amount of heat that will be generated dropping the voltage from the 24V (29.4V) source to provide the required 5V output.

The LM317T can safely be used to dissipate up to 0.25 Watts without a heatsink, but up to 15Watts with a suitable heatsink.

Note that the 15 Watts is an absolute maximum dissipation rating for an LM317T. If you need a voltage regulator which will dissipate more than that, consider the LM338T as an alternative.

Check these links for more useful information:

Using the LM317T as a Voltage regulator

Using the LM317T as a Current regulator

Choosing a suitable heatsink for use with an LM317T voltage regulator

Alan