Sozbots board

Andrew_Hibberd · Post by **Andrew_Hibberd** » Sat Apr 16, 2005 6:11 pm

I have got a sozbots board for icant so i can run two of those sanyo motors, as you may have notced icant has a habit of stripping gears.
If i have the weight left over i may include a saturn s54 servo as the self righting one. To the point the sozbots board has a voltage regulator on it which is rated at 500mah continuous, would i be able to run the s54 using this BEC or would i have to have a sparate one and run it like the bottom diagram on this page http://robotcombat.com/marketplace_soz.html ? It is a case of how much current the little servo will draw as it will be be close to stalling when the ant rights. I have not been able to find current drawn by this servo either.

I am using two lipos and don't want to put 8.4V (or whatever depending on charge etc etc...) into the receiver

Thanks in advance

Post by **BeligerAnt** » Sat Apr 16, 2005 9:31 pm

Andrew, you are right not to power your Rx off of 8.4V (or 7.2V or whatever...) - it will thank you for it!

You can calculate the stall current of a servo motor by measuring its resistance, then calculating I= V/R. For 500mA at 5V you are looking for a resistance of greater than 10 Ohms.

I seem to recall that the Naro HP/BB is about 6 Ohms, but that is quite a high power motor for a 9g servo so I would expect the S54 to have a higher resistance (i.e. lower current and therefore lower power).

Travis7s · Post by **Travis7s** » Thu Apr 28, 2005 5:03 am

I don't know about any of the little receivers... but I've been putting 7.2 v through my more standard sized ones with no problems.

Andrew_Hibberd · Post by **Andrew_Hibberd** » Sat Jul 30, 2005 4:51 pm

I have another question about these dual motor boards.

You can cut them in half, there are connectors on the bottom of the board to connect if this is done. Do i actually have to connect these together as i belive they are a 5V supply a gnd and a Max volt supply, if i where to wire up both halves of the board so they both received the max voltage then surely the ground would go to the RX and the 5V supply {the reg on one half} would go through the RX and into the other half, or should i just solder on the wires?

Sorry it is a rubbish woreded question.

Sozbots says this

Cutting the Board in Half
Cutting the board in half should be done with great care. Make sure to cut along the center line. A sharp
Exacto blade works well. You will be severing 3 connections between the boards which will need to be reconnected.
We do not recommend cutting the board unless it is absolutely necessary.

Post by **BeligerAnt** » Mon Aug 01, 2005 9:57 pm

(Speaking from a slight position of ignorance as I don't have a board to hand...)
You are probably best off connecting both the "Max Volt" (I assume this is the battery voltage?) and the 0V between the boards, or, better still, connecting both back to the battery pack separately.
Do not rely on a 0V connection via the receiver as it will cause you endless interference problems!

Shared current return paths are the biggest cause of interference problems. "0V" is not really 0V until it gets back to the battery! The wire has resistance and inductance and carries various currents. Motor return currents flowing in the 0V lead of your receiver will cause endless problems.

Since the 5V is generated at one motor board and fed through the receiver, it could be linked on to the second motor board this way, but again it would be better (but not so critical) to route it separately.

Hopefully this pic will explain...

Andrew_Hibberd · Post by **Andrew_Hibberd** » Tue Aug 02, 2005 8:59 am

Thanks Gary, i will try that later today