Well here we go again....



First of all a list of the ICs on the board.

Atmega 32A - www.atmel.com/dyn/resources/prod_documents/doc8155.pdf
HEF4051BT - http://www.nxp.com/products/automotive/logic/analog_switches/HEF4051B.html
LM324 - www.national.com/pf/LM/LM324.html
LM2904 - www.national.com/pf/LM/LM2904.html
LM393 - www.national.com/pf/LM/LM393.html

There is also quite a few FETs on the board
FDS7764A - www.datasheetcatalog.org/datasheet/fairchild/FDS7764A.pdf
FDS6675BZ - www.fairchildsemi.com/ds/FD/FDS6675BZ.pdf
IRFZ44N - www.irf.com/product-info/datasheets/data/irfz44n.pdf

Might start on a schematic tomorrow. Initially I thought the ISP header to program the AVR was broken out but it may not be now that I have hacked off the LCD.

No idea what will come of it, my goals are plug and charge BMS one for each robot. @ $20 that is more than feasible these days. It may be more applicable to some other projects I am working on but I am sure people will find a use in their bots. Even if its just a simpler interface to charge your A123s or lipolys.

Steve
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Steven Martin
Twisted Constructions
http://www.botbitz.com

So what I thought was an ISP header is an ISP header.... sweet. Now should go to bed.
_________________
Steven Martin
Twisted Constructions
http://www.botbitz.com

<Insert Zombie Like Here>
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https://www.halfdonethings.com/

Is anyone else worried that there is only one cap for smoothing the voltage out of the step up circuitry......

Printing datasheets, touch is cancelled so hopefully get a bit of time to work on it tonight. (Probably while printing)
_________________
Steven Martin
Twisted Constructions
http://www.botbitz.com

sorry, im just seeking some clarification - what is this project about?

reprogramming lipo chargers - but for what purpose?
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<Patrician|Away> what does your robot do, sam
<bovril> it collects data about the surrounding environment, then discards it and drives into walls

- Plug and play charging (Auto detect cells and charge away)
- logging info of your batteries
- more control over the charging method
- full BMS for non combat robots
- add other features such as motor tester
- general shenanigans with repurposing hardware
_________________
Steven Martin
Twisted Constructions
http://www.botbitz.com

Its the hacker mindset. Taking things apart and making them do other things..

'coz you can

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Great minds discuss ideas. Average minds discuss events. Small minds discuss people

Yep to learn and re-use. I really hate some of the things how the HK firmware does it.

Well who knows who's firmware it is.... Its a copy of a copy of a copy. Its probably not necessary but if I can make it do more things and remove some of the annoyance than I will be pretty happy.

I am considering actually building one into Naked turtle with a secondary battle switch. It would just run all weekend and then I just plug in the power and it charges itself. Like a bought one

Also I hope to use it in other projects for managing and charging lipos in a "real" robot style environment.

Steve
_________________
Steven Martin
Twisted Constructions
http://www.botbitz.com

So the ISP header is definitely functional. But the AVR is locked.

Before I blindly plough into trying to get it to work I decided that I should probably try and trace most of the schematic. I started in Eagle then got distracted by printer again. Get back to it tomorrow.

Edit: Armed with a multimeter, a bright lamp and a pen I have started on paper drawing out the connections. So as far have scoped out the switching pins to the multiplexer (HEF4051) and the connection to the ADC. This appears to multiplex the voltage from the balance leads but need to continue to scope it out tomorrow.


Steve
_________________
Steven Martin
Twisted Constructions
http://www.botbitz.com

^ feel free to remove this once you've seen it cos its huge
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<Patrician|Away> what does your robot do, sam
<bovril> it collects data about the surrounding environment, then discards it and drives into walls

So I have been thinking a bit more about this and how I am going to go about this.

So I think there is a few steps.

1. Initial Schematic
Reverse engineering this should allow me to most of the software implementation but there is only so far you can go before you jump in and do it.

2. Debugging setup
- LCD display
- Serial Comms

3. Readings
- Input Voltage
- Battery Voltage
- Cell Voltages

4. Discharging
- Read Current
- Discharge batteries to set levels.

5. Charging
- Power Circuitry
- Implement Charging Methods

Things start to get interesting around 5ish... but the others are all pretty easy. Once I get serial and LCD working for $17 its in interesting device just to use as that.

Steve
_________________
Steven Martin
Twisted Constructions
http://www.botbitz.com

Feature-Idea.

How about optionally Lobotomising the onboard options and functions and having a mode where the onboard AVR runs a simple serial command-set to report status and control it via a USB-Serial adapter to a PC ?

Commands like "Read Battery Voltage", "Read Cell 1 volts", "Set Charge current to 3 Amps" and so on.

That way you can write a nice GUI with graphs, and easy to operate modes and buttons in a high level language like Python on any platform (PC, Linux, Windows, Android, Phone etc), allowing you to customise functions, update the interface software and so on without having to plug in ISP's to the circuit board all the time.

Saves having to try and implement a meaningful user interface on a 2 line LCD with all the multi-level menus that result

Basically turns it into an external-computer controlled power circuit.

Yo might need some basic failsafe logic on board in case the supervising app dies (commands to set voltage/temp/current shutoff limits)
.

Im doing something similair for the Dashboard/GUI for my Car-Control Project. Theres a chip that does that type of thing for vehicle Can-Bus/OBD Interfaces. The ELM327 Have a look at the spec sheet if you want to get an idera of what it does. http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=4&ved=0CEgQFjAD&url=http%3A%2F%2Felmelectronics.com%2FDSheets%2FELM327DS.pdf&ei=9XgWT_jnOPCwiQfbs4D3Aw&usg=AFQjCNHxmPN_9MzQPh0qsSBZ-hYh9KVT_A&sig2=3x1UCk-RwhzgUesrPF_B6A

Im working on (Well, I was until I moved house in december, just getting the workshop put back together now) *emulating* the ELM327 it with an AVR/Arduino, allowing any pre-OBD car to send sensor info to one of the many OBD Scan/GUI applications like Torque on Android..

Soooo, If you make the charger some form of dumb-remote controlled power circuit with a serial command interface, then the operator interface can be done by a machine more suited to talking to humans (big screen, keyboard, mouse etc).

Its just an idea.. It might be going against your basic plan thought if your goal is more to turn the complex menu driven things into a "plug'n'charge" widget.

At the rate you're going hacking gadgets, you're going win some kind of reverse-engineering award soon.
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Great minds discuss ideas. Average minds discuss events. Small minds discuss people

That is an excellent idea.

Fits in very well with what I am trying to do with it for other projects as well. I think you would still want some of the settings to be held on the charger but this would allow logging and graphing of heaps of interesting stuff online. And many cool additions to be made easily in PC software. I was hoping to be able to use the charger as a BMS system in robots so a lot of this would probably be implemented.

I await the gnireenigne award.

Steve
_________________
Steven Martin
Twisted Constructions
http://www.botbitz.com

LCD repositioned for better accessibility



_________________
Steven Martin
Twisted Constructions
http://www.botbitz.com

First code test.

Also thought of a name for it.

code:

---

/*
SuperCharged
Steven Martin
2012
*/

void main() {

    while(1){
        //Please dont blow up
    }

}

---