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[Reply #15 on:]

Its not 2 - that is what a TIP120 looks like internally.
Really you should be able to drive that relay with just a simple NPN transistor like a 2N2222.

We are in total sync here, I can only suspect miswiring if you can't get that relay to switch for you.

If you hook up an LED and a 220, 270, or 330 ohm resistor, is the pin you're using able to turn the LED on & off?

[Reply #16 on:]

Here is the diagram I created with expresspcb. I couldn't figure out how to get the ground and positive symbols and if I saved as image the traces wouldn't show, so here is a screenshot.


For testing the Motor Controller isn't actually connected to the relay. If I touch the base of the transistor to the battery direcly it works.

I will try the LED when I get home.

The pin worked when I was trying without the relay and also I can measure voltage out of it. I have a command I can set the pin high and low via Xbee.

Its almost like there isn't enough current for the transistor to turn the relay on. We doesn't make sense cause it worked before.

Maybe I should order the TIP102's? Hard to find a place that can ship a few cheap. Jameco has a stupid $10 min and ebay is $14 for 10. Cheapest I found on there that is in the US.

[Reply #17 on:]

I hope to get a proper schematic in eagle this week. If I need to order the TIP102's I want to do it today so they are here by the weekend. Going to have a friend come over and take a look as well.

Thanks again for the help.

[Reply #18 on:]

I just realized there is a ExpressSCH!!!! Oops.

I will play with that when I get home in a few.

[Reply #19 on:]

Yeah, I see you have the pcb layout there.  Still, looks very nice

[Reply #20 on:]

Yeah, I see you have the pcb layout there.  Still, looks very nice

LOL, thanks. 

[Reply #21 on:]

Updated image

[Reply #22 on:]

I tired a LED and it does turn off and on. Using the same pin 51.

[Reply #23 on:]

Ok , the way you show the swithch can't be how you have it wired, nothing would be powered.
Are you sure its not more like this?

[Reply #24 on:]

Which motor controller is it? I can't find it in the thread.

[Reply #25 on:]

Here is the motor controller
http://www.sparkfun.com/products/9571



You are right about the switch, I didn't use it correctly in the diagram. I will fix it.

Thanks.

[Reply #26 on:]

Got some problems here:

The controller uses a 16 MHz ATmega168 - data sheet says it needs ~3.9V to run at 16 MHz, below that operation may become unstable (altho folks have reported good operation down a 3.3V).
If you bring in Vbatt thru JP12 or JP13, it goes thru a regulator. You may have better luck with good comms bringing Vbatt on on  one of the 5V pins on a different connector.

The L298 spec says it needs the motor supply voltage Vs to be the minimum Vin-high voltagte of 2.3V plus another 2.5V - so 4.8V.  So, 3.7-4.2V would seem to be a problem.

[Reply #27 on:]

Oops I forgot to include the step-ups in the diagram... sorry.

[Reply #28 on:]

What are the step ups? How much current are they rated for?

[Reply #29 on:]

What are the step ups? How much current are they rated for?

DC to DC Module based on LM2587 Step-Up (Boost) Regulator

Non-Isolated Steip-Up Module



Input Voltage : DC 3-24V

Input Current : 5Amp (Max)

Output Voltage : DC 4-30v

Output Current : Rated 3A ( peak 5A)

Output Power : 30watt without Heat Sink

35watt with Heat Sink

Output ripple : 20M bandwidth (for reference only)

Operating temperature : Industrial grade (-40 to +85)

Full load temperature rise : 45

Load Regulation : ± 0.5%

Voltage regulation rate : ±0.5%

Dynamic response speed:5% 200uS

Dimensions: Length (3.8 ) * width ( 5.2) * high (2.0) (CM)

Note: There is no Short circuit protection & no Input reverse polarity protection.