mlord
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Nepean, ON
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| reply to MrMazda86
Re: Upgrading Firmware on DCM-476 modems said by MrMazda86:+1 double awesome!! That looks like the kind of creation I'd make. Is it home programmed as well, or do you have some kind of pre-programmed firmware for it? Thanks. It most definitely is "me-programmed" as well, but using the Arduino development tools and libraries.
The fancy blue sub-module is a $3 pre-fab unit off eBay (China). But I just need only the physical card slot from it, and not all of the other stuff. So the built-in 3.3V regulator there is unused, as there's a larger 3.3V regulator on the main board.
Cheers |
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| said by mlord:Thanks. It most definitely is "me-programmed" as well, but using the Arduino development tools and libraries.
Haha... Arduinos are quite the handy little things. They're quite versatile really. |
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mlord
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said by mlord:The fancy blue sub-module is a $3 pre-fab unit off eBay (China). But I just need only the physical card slot from it, and not all of the other stuff. So the built-in 3.3V regulator there is unused, as there's a larger 3.3V regulator on the main board. Speaking of which.. I noticed the main regulator getting unusually hot (thus the heatsink). Today I delved into this some more, and discovered it being due to some interaction with the one on the blue sub-module. So I removed the (unused) regulator from the sub-module, and power consumption is now 1/10th of what it was before. Much better.
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mlord
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2 edits | reply to mlord
Rig #1: going to an ISP. | 
Rig #2: for myself. |
But I can always re-purpose it as a data-logging rig if need be, and I definitely have uses for those from time to time. The extra header on Rig #2 (top edge) is for the main serial port, so I can reprogram it "in-circuit" when needed, but also for logging serial data from a server (needs external level conversion). And there are enough free "holes" in the perfboard to add a couple more I/O headers for temperature monitors or similar.
Cheers |
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 Teddy Boomk kudos Received
join:2007-01-29
Toronto, ON
kudos:7 | reply to mlord
said by mlord:The fancy blue sub-module is a $3 pre-fab unit off eBay (China). Of course there is an even cheaper way to get an SD card slot. Or, more accurately, a micro SD slot. Just solder up an SD to micro SD adapter
But as you've been saying, the real cost behind a flashing rig are the clips.
Are these cheaper than the ones you found before?
»www.mcumall.com/comersus/store/c···uct=4498
Still not really cheap...
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mlord
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| Those clips say $6.62 for a pair of clips, or $3.31/each.
Digikey sells the (superior!) E-Z-Hook XKM grabbers for $3.01/each.
I like the idea for a cheap micro-SD slot, though!
Full-size slots, like the blue one above, go for under $2/delivered on eBay.
But micro slots are really hard to come by at a reasonable price.
Cheers |
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Teddy Boomk kudos Received
join:2007-01-29
Toronto, ON
kudos:7 | Ya, I found that eventually..
There appears to be a variety of generics available.. How bad were the ones you got (from dealextreme I guess?)?
These look a little better than the ones you got, still not good though:
»www.ebay.com/itm/2-x-Grabber-SMD···1be4a176
This guy has a large quantity of Agilent ones for some reason, cheap if you need the numbers:
»www.ebay.com/itm/New-AGILENT-167···2ad#shId
Another seller with the slightly better looking generic:
»www.ebay.com/itm/1-set-4MM-banan···70df3da6
Have you seen this:
»sigrok.org/wiki/Probe_comparison
This was an interesting enough thread, just sticking it here for future reference:
»www.eevblog.com/forum/reviews/ch···gestion/
And linked in that thread, very nice but still not cheap:
»www.ebay.com.my/itm/TEKTRONIX-SM···bb52b8c1
Oh well.. I better get back to work
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Teddy Boomk kudos Received
join:2007-01-29
Toronto, ON
kudos:7
3 edits | edits....
Here we go.. Zeroplus grabbers for $1 each, unknown shipping:
»siliconkit.com/ocart/index.php?r···t_id=218
and these guys not much more with cheap shipping to US addresses:
»store.nkcelectronics.com/view_cart.asp
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mlord
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Nepean, ON
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| reply to Teddy Boom
said by Teddy Boom:How bad were the ones you got (from dealextreme I guess?)? Yes, the generic clips were from dx.com (DealExtreme). I did manage to use them to flash a couple of modems, but the tips on them are about 2X the size of the XKM grabbbers, making it quite difficult to attach them to adjacent pins. And they simply won't fit underneath the DCM-475 heatsinks.
I can give you a handful of them when I return your modems, if you want.
They do make excellent clips for everything except the modems!
Cheers |
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Teddy Boomk kudos Received
join:2007-01-29
Toronto, ON
kudos:7 | Ya, a couple would be great, just to see what I think of them
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mlord
join:2006-11-05
Nepean, ON
kudos:10 | No problem.
I've put two each of five colours (10 in total) into a baggie for you. |
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| lol my dad has a whole bag full of those in the basement from a few decades ago...never knew they were worth that much! Makes me wonder how much the rest of the stuff lying around is worth... |
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| reply to CHRoNiCWiLL
Re: Upgrading Firmware on Thompson DCM475 I have yet to have problems using 3M SOIC clips on these SPI based modems (both 8 and 16 pin variants). I've programmed a considerable amount with them as well. I've ordered them from digikey. My only gripe with digikey is the shipping but they came in one day which was great. The Pomona ones are good as well.
You have to be careful when picking up probes from eBay. I ordered a batch last summer and the pitch on them was not what the auction described, the pitch of the grabbers were too big. I guess you get what you pay for when going the cheap route. |
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mlord
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Nepean, ON
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3 edits | reply to mlord
Re: Upgrading Firmware on DCM-476 modems said by mlord:The 476 probably just has a newer generation chip that uses less power. Neither modem is really "better" than the other, though I do prefer the soft green LEDs of the 475 to the garish blue ones on the 476. Okay, I've taken a current generation DCM-475 modem and compared power consumption with my August/2012 DCM-476 modem. The DCM-475 actually uses ever so slightly less power than the DCM-476.
This is in "idle" mode, with no cable line connected.
And the difference was small, but consistent.
Slightly less than one watt.
0.044 amps @ 125VAC versus 0.052 amps @ 125VAC.
Edit: I've also now measured consumption on my nearly 3-year old DCM-475 that connects us to the internet here, and it shows pretty much the same number as the brand new DCM-475. Both are about 16% more power efficient than the DCM-476, independent of which PSU is used.
There are also slight differences between PSUs, depending upon which stock the manufacturer happened to have on hand when packaging the individual modems. The variance there seems to be within half a watt.
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mlord
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Nepean, ON
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| said by mlord:I've also now measured consumption on my nearly 3-year old DCM-475 that connects us to the internet here, and it shows pretty much the same number as the brand new DCM-475. Both are about 16% more power efficient than the DCM-476, independent of which PSU is used. Heh.. it's probably due to those blindingly bright blue LEDs on the DCM-476. Perhaps I should swap out the resistors on those for higher values and see if the power consumption takes a measurable drop afterward. |
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Teddy Boomk kudos Received
join:2007-01-29
Toronto, ON
kudos:7 | reply to mlord
said by mlord:said by mlord:The 476 probably just has a newer generation chip that uses less power. Funny, but ya, it is probably the LEDs. Even though the 476 draws more, that theory is probably still correct, the CPU probably is a little more efficient.
There is also probably a field failure aspect. Once they know there are very few field failures, they can afford to be a little less conservative about the thermal design.
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Teddy Boomk kudos Received
join:2007-01-29
Toronto, ON
kudos:7 | reply to mlord
Re: Upgrading Firmware on Thompson DCM475 said by mlord:Yeah, the cheapest, easiest way to assemble a rig, is to clone my setup. Parts list with heavy edits:3.3V Arduino compatible chip (eg. Atmega328p, cost $3.50).
clips ($3/each, need 6),
12VDC to 3.3VDC power supply (about $5)
a breadboard ($4)
an SD-card socket (to hold the new firmware) ($10)
a couple of LEDs, resistors, and that's mostly it. So.. I've been trying to source clips, and I can definitely get those Zeroplus ones from China for just under $1 each landed in 200 unit quantity. Or about $1.50 each landed from the US in 20 unit quantity.
I'm sure we could get the DC power cost down below $2 with enough effort, but certainly not more than $3.20 as here:
»dx.com/p/dc-4-5-35v-to-1-25-30v-···d-156808
Micro SD card with converter as socket socket is $4.10 here:
»dx.com/p/2gb-micro-tf-card-with-···k-128032
(but only ~$3.50 if you buy 10)
Then there is the PCB, but that should be cheap enough as well.
Overall, looks like $20 cost is doable. Realistically it would still have to sell for $50 shipped though.
(mlord would have to be paid for his efforts! And others, who contribute significantly to logistics, if that's how things were to go)
The point of all this... Is it worth pursuing any further?
Possible issues:
Should people of varying experience and competency really be attempting this?
(seems to me that isn't a big deal, people will self select--if you can get the modem open, you can probably handle the electronics)
Do theft of service issues make this a bad idea?
Overall, I'm really not sure what I think, but it is worth discussing.
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mlord
join:2006-11-05
Nepean, ON
kudos:10 | Want me to bring you a pre-programmed Atmega328p when I visit (about 10 days from now) ? |
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| mlord,
I sent you an email, not sure if it got thru, since I couldn't remember my old username and password....If you dont get it, can you send me a PM with an email address to get at you with, so I can get my modem upgraded to avoid the disconnects |
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mlord
join:2006-11-05
Nepean, ON
kudos:10 | You've got a PM. |
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