2 Channel LCD Charger Discussion

Forum for announcements and discussion of beta firmware.
Paul.Allen
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Re: Discussion of Mark's firmware

Postby Paul.Allen » Fri Nov 15, 2013 9:41 pm

As far as chips go, based on the comments that have been rolling in from the latest kickstarter update, looks like it is going to be the ARM. This will also still keep it fully Arduino compatible for the few people that it is really important to.

Mark
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2 Channel LCD Charger Discussion

Postby Mark » Sat Nov 16, 2013 9:14 am

Paul.Allen wrote:As far as chips go, based on the comments that have been rolling in from the latest kickstarter update, looks like it is going to be the ARM. The will also still keep it fully Arduino compatible for the few people that it is really important to.


Yep - the responses so far look really good - I don't think that there is anyone who has commented that would be unhappy with option 4!

A couple of questions though:

Is there a reason (other than possibly cost) why you're wanting to stick to 3 buttons? Most hobby chargers have 4 buttons and I think that's the way to go - although a menu could be done with 3 buttons, I think that 4 buttons would make it easier/nicer to use.

Have you included the cost of a small EEPROM chip in the $8 cost? I think that would make things easier for me and would make it closer to the 4 cell version - the 4 cell version should definitely have an EEPROM IMHO.

For those wanting to go straight to the 4 cell version, I'd suggest that they should take the 2 cell LCD version when it's available and then buy the 4 cell version when it becomes available - I think that there would definitely be a market for those that don't want to have both to sell their 2 cell chargers to the people that missed out on getting a charger through Kick Starter. Even when the 4 cell version is available there should still be demand for the 2 cell version since it won't cost as much.

Mark
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Re: Discussion of Mark's firmware

Postby Mark » Sat Nov 16, 2013 9:31 am

With regard to time frames, I'm assuming that you're meaning the end of the calendar year that you want to get everything shipped out by?

To be honest, I really can't see that happening with option 4. Even if you were to stick to the current LCD design, I think we'd be pushing it to do it by the end of the year - we're rapidly approaching 5 months since the Kick Starter funding period ended and the non LCD versions aren't fully shipped yet, so I don't think it would be realistic to get the rest done and shipped in 6 weeks...

Sorry to be a party pooper!

Mark
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Re: Discussion of Mark's firmware

Postby Mark » Sat Nov 16, 2013 2:21 pm

I've had some further thoughts about the EEPROM:

Although it might be possible to use the flash memory in the controller as a substitute, it's by no means guaranteed to work and will definitely take time to work out either way. I think it would definitely be a lot quicker to add an external EEPROM chip such as one of these:

http://www.newark.com/atmel/at24c02c-sshm-b/serial-eeprom-ic/dp/68T4066

In quantities of 100+ they're only 12.9c each - for 150 chargers, it would work out to less than $20 for all of them combined!

Paul.Allen
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Re: Discussion of Mark's firmware

Postby Paul.Allen » Sat Nov 16, 2013 5:56 pm

Mark wrote:With regard to time frames, I'm assuming that you're meaning the end of the calendar year that you want to get everything shipped out by?

To be honest, I really can't see that happening with option 4. Even if you were to stick to the current LCD design, I think we'd be pushing it to do it by the end of the year - we're rapidly approaching 5 months since the Kick Starter funding period ended and the non LCD versions aren't fully shipped yet, so I don't think it would be realistic to get the rest done and shipped in 6 weeks...

Sorry to be a party pooper!


You are fine Mark. I guess I need to put up another clarify. Basically I need to have the hardware designed and have ordered all the parts including the final PCB's by the end of the year. As far as shipping goes I realize that is unrealistic but I still need to pay the shipping this year. The way I am going to do that is pre-buying the shipping as close as I can estimate and then I will just have to pay any extra when I actually ship. I plan to take full advantage of the chips USB to make updating software easier (as well as any of your ideas to have it update from the SD card). So I think I will feel okay shipping the hardware as soon as I get it done rather than waiting until the firmware is all good. You are right about it taking longer than, from now until the end of the year, but I hope this makes more sense.

Paul.Allen
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Re: Discussion of Mark's firmware

Postby Paul.Allen » Sat Nov 16, 2013 5:56 pm

Mark wrote:I've had some further thoughts about the EEPROM:

Although it might be possible to use the flash memory in the controller as a substitute, it's by no means guaranteed to work and will definitely take time to work out either way. I think it would definitely be a lot quicker to add an external EEPROM chip such as one of these:

http://www.newark.com/atmel/at24c02c-sshm-b/serial-eeprom-ic/dp/68T4066

In quantities of 100+ they're only 12.9c each - for 150 chargers, it would work out to less than $20 for all of them combined!


That should work!

Mark
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Re: Discussion of Mark's firmware

Postby Mark » Sun Nov 17, 2013 4:23 am

Paul.Allen wrote:
Mark wrote:I've had some further thoughts about the EEPROM:

Although it might be possible to use the flash memory in the controller as a substitute, it's by no means guaranteed to work and will definitely take time to work out either way. I think it would definitely be a lot quicker to add an external EEPROM chip such as one of these:

http://www.newark.com/atmel/at24c02c-sshm-b/serial-eeprom-ic/dp/68T4066

In quantities of 100+ they're only 12.9c each - for 150 chargers, it would work out to less than $20 for all of them combined!


That should work!


A couple more options while they're on special:

Double the size for 9.9c each:
http://www.newark.com/on-semiconductor/cat24c04yi-gt3/ic-eeprom-4kbit-serial-400khz-tssop/dp/08R5405

8 times the size for 14.2c each:
http://www.newark.com/on-semiconductor/cat24c32wi-gt3/ic-eeprom-32kbit-serial-400khz/dp/08R5414

I'd be inclined to go for the larger size (and buy enough for the 4 channel version as well) It's not that much money and it's better to have space we don't need than to regret not having it later...

Mark
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Re: Discussion of Mark's firmware

Postby Mark » Sun Nov 17, 2013 5:11 am

Paul.Allen wrote:You are fine Mark. I guess I need to put up another clarify. Basically I need to have the hardware designed and have ordered all the parts including the final PCB's by the end of the year.


Ah... In that case, I think it would be a good idea to consider sending a prototype to me using Fedex or similar as soon as you have them so that we're not cutting into the remaining 6 weeks we've got. I'm going to be away over Christmas so it's really only 5 weeks left. Take off a couple more weeks for design and production of the prototype and we're still cutting it a bit fine!

You could also send the rest of the Australian orders along with my non LCD chargers in the same package to make it more worthwhile. How does that sound?

In the end, it might be better to take the hit (presumably you'll get a tax refund the following year?) than to risk sending off for boards that turn out to be unusable or you're not happy with.

As far as shipping goes I realize that is unrealistic but I still need to pay the shipping this year. The way I am going to do that is pre-buying the shipping as close as I can estimate and then I will just have to pay any extra when I actually ship.


Cool - I didn't know that you could do that! (Edit: actually, you can do that in Australia with packaging that has the postage prepaid, so I shouldn't be surprised that's possible!)

Is there any chance of maybe prepaying for the board production as well? That would take some of the pressure off so that there's less risk of ordering a batch of useless boards...

I plan to take full advantage of the chips USB to make updating software easier (as well as any of your ideas to have it update from the SD card). So I think I will feel okay shipping the hardware as soon as I get it done rather than waiting until the firmware is all good. You are right about it taking longer than, from now until the end of the year, but I hope this makes more sense.


Yep - I think that all makes sense.

Have you got in mind a specific alternative to the ATSAM3X8EA-AU? I had a bit of a look around but didn't find anything that I thought would be better. I found some cheaper options but at the cost of losing some good features.

Unless there is a good reason for an alternative, I think it would be nice to stick with the ATSAM3X8EA-AU - keeping it Arduino compatible will make development a bit simpler as well as keeping others happy. If you did choose something that was incompatible, I don't see why you couldn't refund those that were unhappy with the decision - there seems to be plenty of people who would be willing to take their boards and pay for the privilege.


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