Hack / Interface a Digital COin Counting Jar ?

T&E Engineer

Has anyone tried to do this with a BS2 or a SX28 ?

http://shop.avon.com/shop/product.asp?pf_id=31225&from=search&find_spec=coin%20bank&camp=200715&dir_delivery=1&rep_delivery=1

OR

http://www.target.com/gp/detail.html/sr=1-5/qid=1183937496/ref=sr_1_5/602-9806967-8317438?ie=UTF8&asin=B000ODRMLS

We have one from Avon and they are pretty smart. I would like to try to replace the controller (probably a PIC) with an SX or BS2. I·have ordered another one.·

I have got no idea how to get the right switch for this so I want to examine a working one.

Post Edited (T&E Engineer) : 8/5/2007 9:58:51 PM GMT

T&E Engineer

I got my Avon coin bank tonight and had to buy a cordless dremel. The LCD is not usable and presses against the PCB of an unknown IC. I decided to use a larger 2x16 backlit LCD screen which will take up much more space on the top of the bank. I have attached some pics of the electronics and switch mechanism as well as the parallax LCD. As you can see the original bank LCD has no wires and just fits over the PCB. As I was planning on replacing the PCB anyway with an SX28, I will just have to replace the original LCD with a much larger Parallax LCD. I will be able to do much more with this setup.

Does anyone know if this setup will run under 2 AA batteries or should I add a 4xAA pack instead?

It is certainly much more expensive having to add another LCD and buy a dremel tool but it will be awesome at the end. I will continue to post pics during the process.

Chris Savage

It appears the bank knows the value of a coin by measuring its diameter. Weird. I guess I expected something more. Interesting concept, but you couldn’t use it on a public device that accepted coins.

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Chris Savage
Parallax Tech Support

T&E Engineer

Chris,

That's right. There are no smart's in the slide switch. It only makes contact with 1 of 6 positions (dime, penny, nickel, quarter, 50cents, dollar coin). It is one step under using push buttons to register a coin drop (but this is a little more fun with the sliding switch).

I have some code but it is not quite ready to post yet as I am working on adding an EEPROM and code so that if power goes out, the total coin count is not lost.

T&E Engineer

I have made some great progress on this project (with the SX/B code) today Thanks to Bean and JonnyMac especially.

The code runs well and I hope to have it assembled with more pictures either this weekend or during the upcomming week.

Currently I have it connected to my Professional Development Board (PDB) using an SX28, 4 MHz resonator, an EEPROM such as a 24LC32A (to save the total money count if power is lost) and a backlit Serial LCD. It also temporarily uses the 8 pushbuttons on the PDB to simulate the Coin counting jar sliding switch for coin drops.

I'm very impressed with the emulation hack on this project. If you have a chance try connecting it to a PDB and have fun!

Now I have to do the following:

1. Decide how to make the LCD display more interesting (not bad how it is now).

2. Sandpaper scratches out (from dremmel tool) and paint with Krylon Fusion paint for plastics.

3. Solder SX28 circuit together and mount to underside of jar top.

4. Mount 4 AA battery pack to underside of jar top. ((Find a way to reduce this to +5vdc))

5. Misc. other related tasks.



More to come...

T&E Engineer

Here are some more pictures.

I spray painted it and it has a grey/black hammered tecture which is kind of neat.

I also used my new dremmel to take away the built in 2x AA battery holder and used some heavy duty doublesided tape to attach a 4x AA radio shack battery holder. Unfortunately it hangs down a little and is noticible through the see thru plastic money jar.

I also ordered some LT1121 samples from Linear Technologies that I saw that the Parallax·RobOlympics badge used for 6vdc batteries·to 5vdc. I also bought a 5.1v zenier diode that I may also try but I think the LT1121 will work better.

I have to find a place for the SX28, resonator, regulator circuitry, etc. Probably a tight fit. I also want to try and add a 4 pin programming connector for easy upgrades.

More later this week.



·I just realized that the Parallax serial LCD was mounted upside down which is ok but I changed it back around. This is noted in Bank8.jpg. No wonder it was a tight fit (upside down).


Post Edited (T&E Engineer) : 8/7/2007 12:43:26 AM GMT

T&E Engineer

I soldered the SX28, resonator, EEPROM and socket for the LT1121 (regulator - waiting for my free sample in the mail). Here are some pics. I did have to use the dremmel again to cut open the case a bit for the LCD cable and SX-Key. When the regulator comes in, I will have to solder the· 8 wires from the slide switch and reset button to the top of the (8) 220 resistors and thats about it. It was a tight fit.