Has been pass a long time since my last post, and well, I have been very busy. Anyway I have a good gift for all the community and I hope you will enjoy it, is my final version of my MUX antifail system. Chris Anderson already talk about this, you can see it here.
This device let you switch between automode or manual mode just using 1 channel of your remote control. My Antifail system is a little bit complex, the idea was to make it very flexible and you can adapt it to any homemade solution.. For example you can choose between a pull down or pull up resistor, and if you make contact with any servo activated device in the correct pins will let you switch between modes or if you system only have a TTL pin to send the signal you can use it with no problems… in other cases if you have weird pico-switch that is just a transistor that makes ground, anyway, you can use it, (maybe I confuse everybody now), this is just an introduction, but I will explain it in detail after.
And off course if open source and almost free, (just 7 dlls for board), a commercial one will cost you about $50 dlls.
Let me explain about the labels of the PCB:

SA1,2,3,4= Servos Port A (Input): Input of servos in port A.

SB1,2,3,4= Servos Port B (Input): Input of servos in port B.

S1,2,3,4= Servos Outputs.

PWR_SEL= Power Select Jumper: Let you choose from where you want to obtain the power to move the output servos, if you place the jumper in the pins 1 and 2 you will take the power from the receiver connected to input port A, and if you put the jumper in pins 2 and 3 you will obtain the power from the receiver connected to input Port B.

IC_PWR= IC power select: This jumper let you choose from where you want to take the power to supply the multiplexor chip, if you place the jumper in pins 1 and 2 (SRV), you will obtain the power from the receiver selected in PWR_SEL, but in case that the receiver exceeds 5.5 volts, you will need to place the jumper in the pins 2 and 3 (VIN), and connect a 5 volts battery in the VIN jumper.

VIN= Voltage In: Here is where you suppose to connect the 5 volts battery. Careful with the polarity =).

RES_SEL= Resistance Selector : Here you can choose between a pulldown or pullup resistor, if you choose pulldown resistor, the autopilot will be disable by the default, until you send a 5 Volts signal. If you select the pullup resistor, the autopilot will be activated by default, until you ground it.

PICO= PICO Switch, is where you suppose to connect a switch activated by a servo signal (connected to channel 5 of your remote control). The pin 1 is ground, the pin 2 is the mode selector (manual mode or auto mode) and the pin 3 is 5Volts. If you selected the pulldown resistor mode you will need to make contact between the pin 2 and 3 to activate or deactivate the autopilot,. In case that you selected the pullup resistor mode, you will need to ground the pin2 to activated or deactivate the autopilot, you can use any ground you want, but I already put you a ground pin, and is the pin1 =).
In case that you have system that will send a TTL signal, like a microcontroller or something, you should connect the output pin of your MCU and connect it to the “PICO pin 2” (the middle one), and connect the ground of the MCU to the MUX Ground, in this case the ground pin (PICO pin 1).
Just to rectify if the pin 2 of the PICO jumper is set to LOW or ground, the input port A will be redirected to the output port (you can connect here your receiver or you autopilot). If the pin is set to HIGH or 5 volts, the input ports B will be redirected to the output ports, instead the input port A. This will let you switch between to controllers (autopilot and the remote control receiver).

LED1= Tells you when autopilot is activated or vise versa..

LED2= Tells you when the system is powered..

Well I hope is enough… If I made a grammatical mistake (like always) just tell me, hehe.
To order a PCB from PCBbatch.com click here.


About the Pico Switch, you can buy it from here:
http://www.dimensionengineering.com/PicoSwitch.htm
Or you can make you own, the switch is from radioshack:

Use it by your own risk!!, if you plane crash i don't know anything, i don't even exist for you, but if you plane is a successful, all the credit is mine off course =P

Views: 2143

Tags: jordi, multiplexor, mux


3D Robotics
Comment by Chris Anderson on May 8, 2008 at 7:31pm
Hey Jordi,

Great start! Do you have links to the other components needed?

3D Robotics
Comment by Jordi Muñoz on May 8, 2008 at 7:36pm
ahh yes i already test it, works fine, the main component is the 74ls157, anf you can request free samples here (10 units):
http://focus.ti.com/docs/prod/folders/print/sn74ls157.html

And the remaining parts are just 1 resistor of 5kohms, 3 resistors of 220 ohms, 2 leds, and normal pin headers, or you can use servo wire with the header just for luxury..

Enjoy!!
Comment by James Ross on May 8, 2008 at 9:34pm
This looks great, Jordi.

I think you forgot to mention the two jumpers required in your parts list.

Any plans for a built-in switch?

3D Robotics
Comment by Jordi Muñoz on May 11, 2008 at 10:43pm
Yes.. i already made one. and you going to see it in the "World Most cheaper autopilot", anyway i will make a special edition, just for the antifail system..
Comment by ryan reeve on April 11, 2009 at 12:39am
can somebody post schematic and pcb files
regards..
Comment by karthi.joy1988 on December 9, 2010 at 1:12am
hi i'm karthi, i want best arduino board can you tell me
Comment by karthi.joy1988 on December 18, 2010 at 12:01am

hi jordi munoz.............pls tell me how to start a ardupilot project

i'm waiting  for yo response.............

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