By this ground supply, do you mean the ground of the smart motor or a different one? Just want to be sure I know what you mean.
Of course, no problem- I'll try to explain more concisely:
What I mean at the simplest level is don't break (switch on/off) any of the grounds. And especially not those parts potentially drawing a large current (ie. the smart motor and DHB10). Switch only the positive rails where needed.
Your original sketch, and the detailed diagram indicates the AB powered from USB, and the DHB10 powered from the battery. So the AB has it's ground referenced to the PC's ground, and the DHB10 is referenced to the battery. The only thing linking the two grounds together is the 3-pin (white-red-black) cable between the AB and DHB10.
The smart motor on the other hand is connected to both the battery ground and the PC's ground (via the RS232-to-USB adapter).
Thus, if you switch off the ground connection that is between the smart motor and the battery, then the smart motor (being smart!?) can still find a path to battery ground taking the loop via the PC (ie. RS232-to-USB, PC, USB-to-AB, DHB10, Battery). There's a good chance that won't end well for anything in that path if the smart motor is attempting to turn a motor (ie. draw large current).
Acronyms get so confusing sometimes...for years we had a board called, "Professional Development Board", which we called, PDB for short. Then we made a Propeller version of it, "Propeller Professional Development Board". But both were discontinued and now we have the, "Power Distribution Board" for both Arlo and ELEV-8. So yeah...fun times.
We used an oscilloscope with a shunt resistor and found a tiny blip of ~400mA!! for 100 nanoseconds when the power switch was flipped. There was no smoke when I fried the board, validating my hunch that a spike that small couldn't cause smoke yet did fry something internally. All is good now!
1. Add 10 k ohm resistors to all wires between the Propeller and the DHB-10 to protect the servo pins (P12 and P13).
2. Completely disconnected the 5v red wires between the Propeller and DHB-10--the DHB-10 does not require any power and I thought better safe than sorry.
3. Hardwired the ground of the Smart Motor to other grounds so even if the motor is turned off (by toggling the 24V and the series/parallel switchup), the ground is always connected.
I took a look at the Arlo power distribution board and would suggest wiring battery B3 and the smart motor as in the attached drawing. It takes advantage of the connections and motor fuse on the PDB, provides a common ground for all the batteries, permanently connects the smart motor to the common ground, and allows all three batteries to be charged from the barrel connector.
On top of that it should make the wiring simpler and neater.
Thanks for looking that up, I'm figuring this board is out of production. It's on my wish list along with the BS2 module. Links on that page back to Parallax come up a dead end. What is the price they are asking, looks outrageous in any currency.
Thanks for looking that up, I'm figuring this board is out of production. It's on my wish list along with the BS2 module. Links on that page back to Parallax come up a dead end. What is the price they are asking, looks outrageous in any currency.
You can find them on ebay from time to time for a hundred bucks.
Thanks for looking that up, I'm figuring this board is out of production. It's on my wish list along with the BS2 module. Links on that page back to Parallax come up a dead end. What is the price they are asking, looks outrageous in any currency.
Hello!
Want one Mike? I still have items left from the last give-away cycle.
Hello!
Want one Mike? I still have items left from the last give-away cycle.
I would be happy to pay shipping on something like that. Wow that would be great to have the module alone, the PDB if I'm right would be the cake. PM Welcome Buck!
Buck, I take it I may have insulted you, taking for granted these items were still on a give away status.
Please come up with a reasonable price, and I see what I can do. It isn't absolutely necessary that I have these items, but it would be nice to have the BS2 PDB alongside my PPDB, ready when I get the whim to work with the BS2.
Comments
That's the one!
Actually 3, if you count the remaining stock. Get 'em whilst you can!
Professional.
Only Picture I could find:
https://www.fabtolab.com/professional-development-board
Of course, no problem- I'll try to explain more concisely:
What I mean at the simplest level is don't break (switch on/off) any of the grounds. And especially not those parts potentially drawing a large current (ie. the smart motor and DHB10). Switch only the positive rails where needed.
Your original sketch, and the detailed diagram indicates the AB powered from USB, and the DHB10 powered from the battery. So the AB has it's ground referenced to the PC's ground, and the DHB10 is referenced to the battery. The only thing linking the two grounds together is the 3-pin (white-red-black) cable between the AB and DHB10.
The smart motor on the other hand is connected to both the battery ground and the PC's ground (via the RS232-to-USB adapter).
Thus, if you switch off the ground connection that is between the smart motor and the battery, then the smart motor (being smart!?) can still find a path to battery ground taking the loop via the PC (ie. RS232-to-USB, PC, USB-to-AB, DHB10, Battery). There's a good chance that won't end well for anything in that path if the smart motor is attempting to turn a motor (ie. draw large current).
Does that help?
We used an oscilloscope with a shunt resistor and found a tiny blip of ~400mA!! for 100 nanoseconds when the power switch was flipped. There was no smoke when I fried the board, validating my hunch that a spike that small couldn't cause smoke yet did fry something internally. All is good now!
Thank you to those who helped!
Henry
1. Add 10 k ohm resistors to all wires between the Propeller and the DHB-10 to protect the servo pins (P12 and P13).
2. Completely disconnected the 5v red wires between the Propeller and DHB-10--the DHB-10 does not require any power and I thought better safe than sorry.
3. Hardwired the ground of the Smart Motor to other grounds so even if the motor is turned off (by toggling the 24V and the series/parallel switchup), the ground is always connected.
H
I took a look at the Arlo power distribution board and would suggest wiring battery B3 and the smart motor as in the attached drawing. It takes advantage of the connections and motor fuse on the PDB, provides a common ground for all the batteries, permanently connects the smart motor to the common ground, and allows all three batteries to be charged from the barrel connector.
On top of that it should make the wiring simpler and neater.
Hope you're sortin' out your shortnin'. Prop lives matter!
Thanks for looking that up, I'm figuring this board is out of production. It's on my wish list along with the BS2 module. Links on that page back to Parallax come up a dead end. What is the price they are asking, looks outrageous in any currency.
You can find them on ebay from time to time for a hundred bucks.
http://www.ebay.com/itm/Basic-Stamp-Microcontroller-Professional-Development-Board-with-many-Extras-/272539189386?
Hello!
Want one Mike? I still have items left from the last give-away cycle.
I would be happy to pay shipping on something like that. Wow that would be great to have the module alone, the PDB if I'm right would be the cake. PM Welcome Buck!
Please come up with a reasonable price, and I see what I can do. It isn't absolutely necessary that I have these items, but it would be nice to have the BS2 PDB alongside my PPDB, ready when I get the whim to work with the BS2.
Sorry for the confusion.
Mike