Question: How Can Dollar Tree Sell A Scientific Calculator For A Dollar?  - Page 1
Forum section: electronics / general

author: bullet308
author_rank: Frequent Contributor
timestamp: September 25, 2012, 12:35:39 am
content: Answer:...well, lets just say they cut a couple of corners....

author: IanB
author_rank: Super Contributor
timestamp: September 25, 2012, 01:02:53 am
content: Well, what corners did they cut?Does it work? Does it have any bugs you can find?I grant you it would be hilarious to take such a device back in time with a time machine and show it to someone laboring over log tables to do scientific calculations in the 19th century, and tell them, "oh, by the way, this thing is so cheap you could buy five of them for the price of a cup of coffee", but then I don't think they would like you very much...

author: bullet308
author_rank: Frequent Contributor
timestamp: September 25, 2012, 01:13:03 am
content: The corner I was most struck by was the printed paper circuit board....I knew this was possible, but had yet to run across it in a commercial product, even one from a dollar store. Not surprisingly, most of the complaints in the reviews on the Dollar Tree web site are about how they work great, but don't last very long. I think I understand why now...Neat technology, actually. It does seem to work just fine. Nothing wrong with the feel of the keyboard, the display, the functionality...I just wish I could get the same calculator with a real PCB for the keypad for twice or even three times the price...but you cant. :-/

author: amyk
author_rank: Super Contributor
timestamp: September 25, 2012, 09:31:59 am
content: Paper? Are you sure it's not polyester or similar plastic materiallike HP used in their calculators?Also a quick Google on the model number reveals that it's made by... Mastechhttp://mastechelectronic.by-trade-shows.com/Scientific-Calculator.htmlTheir longevity (or lack thereof) is probably more attributed to how people tend to treat them.

author: bullet308
author_rank: Frequent Contributor
timestamp: September 25, 2012, 11:04:43 am
content: The board material seems to be something in-between paper and plastic...perhaps some sort of polymerized paper product? Matte finished on the printed side, semi-glossy on the other.It seems to have a fine granular structure to it under 30x magnification, so I believe it started out as paper, if nothing else.BTW, the traces are a dark gray in color and exhibit relatively high resistance (about .01 ohm per cm). Probably printed lithographically, perhaps on an offset duplicator. The ribbon cable is probably attached using conductive glue. VERY cheap to make. You could probably just neck down the traces a bit and do some of your resistors that way.

author: bullet308
author_rank: Frequent Contributor
timestamp: September 25, 2012, 06:19:10 pm
content: Dollar Tree as a big chain is relatively good about upholding the quality of their products...relatively being, of course, a relative term in the context of dollar stores. At least, they don't get a lot of recalls for stuff burning peoples houses down or poisoning people. I call that a win, in any case. :-)They don't seem to do a lot of one-shot buyouts and such. We have Big Lots/Odd Lots for that. They used to be pretty flaky quality-wise (out-of-date oatmeal being circled by baby moths, that sort of thing), but have gotten a lot better in recent years.

author: amyk
author_rank: Super Contributor
timestamp: September 26, 2012, 08:40:34 am
content: Quote from: bullet308 on September 25, 2012, 11:04:43 amIt might be something like Tyvek, polyester fibers that are pressed together. The matte is so the conductive carbon-based ink can stick to it when they print the circuit. The connections look like heat-seal made with ACF.QuoteYou'd be surprised. Moulding process and the raw plastic is incredibly cheap, the ASIC literally costs pennies, same with the display. The batteries are probably the most expensive parts here. (Expensive being a relative term.)