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Flash with 2.5mm Headphone Jack
01-30-2015, 11:11 PM (This post was last modified: 02-10-2015 06:29 AM by BarryMead.)
Post: #1
Flash with 2.5mm Headphone Jack
A while back Marcus von Cube posted a thread on how to flash a WP-34S with a 2.5mm headphone jack. here This posting is similar to his with a few simplifications. I decided to mount the 2.5mm headphone jack in the center of the calculator along the top edge. With this mounting arrangement it is easier to cut away the plastic of the case to make room for the jack, and you don't need to cut away any of the mounting struts. Since I already owned one of the FTDI TTL-232R-3V3-AJ cables from another project my cost to build was less than with Harald Pott's USB board. See the attached photos. There is one advantage to this connector over the USB connector. If you have two or more calculators built in this way, you can use a 2.5mm crossover cable to transfer programs and data directly from one calculator to the other without a computer. The spreadsheet shows two extra SMT capacitors, because they seem to go flying across the room when I try to hold them with a pair of tweezers.
           
The connections are:

1. Tip (USB Cable TX) goes to JP5 (Calculator RX)
2. Ring (USB Cable RX) goes to JP6 (Calculator TX)
3. Sleeve (USB Cable Gnd) goes to Battery Minus (Calculator Gnd)

The attached spreadsheet shows where to order everything to make your own WP-34S with the 2.5mm headphone jack. If you order everything it costs more than with Harald's USB board, but I already owned the cable so it cost less in my case.


Attached File(s)
.xls  BOM-Serial.xls (Size: 14.5 KB / Downloads: 28)
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01-30-2015, 11:53 PM
Post: #2
RE: Flash with 2.5mm Headphone Jack
(01-30-2015 11:11 PM)BarryMead Wrote:  A while back Marcus Von Cube posted a thread on how to flash a WP-34S with a 2.5mm headphone jack. This posting is similar to his with a few simplifications. I decided to mount the 2.5mm headphone jack in the center of the calculator along the top edge. With this mounting arrangement it is easier to cut away the plastic of the case to make room for the jack, and you don't need to cut away any of the mounting struts. Since I already owned one of the FTDI TTL-232R-3V3-AJ cables from another project my cost to build was less than with Harald Pott's USB board. See the attached photos. There is one advantage to this connector over the USB connector. If you have two or more calculators built in this way, you can use a 2.5mm crossover cable to transfer programs and data directly from one calculator to the other without a computer.

The connections are:

1. Tip (USB Cable TX) goes to JP5 (Calculator RX)
2. Ring (USB Cable RX) goes to JP6 (Calculator TX)
3. Sleve (USB Cable Gnd) goes to Battery Minus (Calculator Gnd)


The attached spreadsheet shows where to order everything to make your own WP-34S with the 2.5mm headphone jack. If you order everything it costs more than with Harald's USB board, but I already owned the cable so it cost less in my case.

Cool idea Barry, will make it simpler for lots of folks. I guess I missed Marcus' earlier suggestion.

FYI - when I click the thumbnails, new pages open with photos, but those photos are the same size as the thumbnails (prob just pointing to wrong set of pics)

--Bob Prosperi
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01-31-2015, 01:10 AM
Post: #3
RE: Flash with 2.5mm Headphone Jack
(01-31-2015 12:06 AM)BarryMead Wrote:  
(01-30-2015 11:53 PM)rprosperi Wrote:  Cool idea Barry, will make it simpler for lots of folks. I guess I missed Marcus' earlier suggestion.

FYI - when I click the thumbnails, new pages open with photos, but those photos are the same size as the thumbnails (prob just pointing to wrong set of pics)
I had to scale the photos down to really small or the forum rejected them. It has a size limit of 500k total for all attachments. I wanted to post larger photos, but kept getting the "TOO BIG" warning.

Yeah, its a frustrating limit, though I understand why it's needed.

With the ever dropping price of "cloud storage", there must be some simple and cheap way to add space, but no idea how/where this is hosted; maybe Dave self-hosts? Of course cheap is really cheap if someone else is paying, but I'd make a donation if it would help.

--Bob Prosperi
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01-31-2015, 08:31 AM
Post: #4
RE: Flash with 2.5mm Headphone Jack
(01-31-2015 12:06 AM)BarryMead Wrote:  I had to scale the photos down to really small or the forum rejected them. It has a size limit of 300k total for all attachments.

Instead of complaining, how about ...
a) writing 3 posts, each with just 1 photo?
b) cutting the photos to just show the interesting parts?
c) combining tip a) and b)?

SCNR
d:-/
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01-31-2015, 09:17 AM
Post: #5
RE: Flash with 2.5mm Headphone Jack
(01-31-2015 12:06 AM)BarryMead Wrote:  I had to scale the photos down to really small or the forum rejected them. It has a size limit of 300k total for all attachments. I wanted to post larger photos, but kept getting the "TOO BIG" warning.
Try resaving your images with less quality but not resize. Such as Q = 50 will be almost no noticeable compression artifacts but the file size will decrease more than ten times
http://en.wikipedia.org/wiki/JPEG#Sample_photographs
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01-31-2015, 09:58 AM (This post was last modified: 01-31-2015 10:26 AM by BarryMead.)
Post: #6
RE: Flash with 2.5mm Headphone Jack
(01-31-2015 09:17 AM)Leonid Wrote:  Try resaving your images with less quality but not resize. Such as Q = 50 will be almost no noticeable compression artifacts but the file size will decrease more than ten times
http://en.wikipedia.org/wiki/JPEG#Sample_photographs
Thanks for the excellent tip. I was able to use larger scale photos with lower quality that look much better and clearly show the intended techniques.
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01-31-2015, 11:25 AM (This post was last modified: 01-31-2015 12:16 PM by walter b.)
Post: #7
To the forum administrators
This is another thread hiding 4 posts.

d:-(
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01-31-2015, 03:52 PM
Post: #8
RE: Flash with 2.5mm Headphone Jack
(01-31-2015 09:58 AM)BarryMead Wrote:  I was able to use larger scale photos with lower quality that look much better and clearly show the intended techniques.

MUCH better, thanks Barry.

--Bob Prosperi
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