p3 4400 surface mounted chip

XBee projects like the adapter, xBee tutorials, tweetawatt/wattcher, etc. from Adafruit

Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.
Locked
chickensandwich
 
Posts: 5
Joined: Mon May 11, 2009 8:59 am

p3 4400 surface mounted chip

Post by chickensandwich »

I just took apart a new p3 4400 kill-a-watt and noticed that it has a surface mounted 2902 chip located behind the lcd. Has anyone soldered this setup yet? It looks like the people at p3 designed the pcb in such a way to prevent hacking.

Does any one know of a retail store, such as walmart, that carries the kill-a-watt. I'm having a hardtime finding them locally and I've been outbid on ebay for the last time.

On another note I found a great deal on amazon for a Aoyue 968 digital hot air/iron for $159. If the wife let's me I'm buying it, and completing this tweet-a-watt project.

adafruit
 
Posts: 12151
Joined: Thu Apr 06, 2006 4:21 pm

Re: p3 4400 surface mounted chip

Post by adafruit »

see http://www.ladyada.net/forums/viewtopic ... 40&t=11009
it looks like a new revision came out in between the project design and publication.
dont worry tho, im sure it's still possible!

chickensandwich
 
Posts: 5
Joined: Mon May 11, 2009 8:59 am

Re: p3 4400 surface mounted chip

Post by chickensandwich »

Yes, the pinout is the same however it was a little tricky. The op-amp is under the lcd and the perimeter of the bottom of the lcd is foam, I had to cut little paths through the foam for the wires to run and cut little notches on the pcb to get the wires to the other side. The lcd has an inductive connection that has to lay flat and this only way I could get it to work.

I did run into a little problem, when I plug in the kill-a-watt the display will fade in and out, fading when the zigbee transmits. I have read the post about plugging it in waiting two seconds, unpluging, and then plug back in and the same thing happens. I have verified that the capacitors are wired correctly. I still have to cut the heatshrink to verify the diode is positioned correctly.

adafruit
 
Posts: 12151
Joined: Thu Apr 06, 2006 4:21 pm

Re: p3 4400 surface mounted chip

Post by adafruit »

you could try putting in an even bigger super cap
does the KaW reset or just fade? does it get better over time?

chickensandwich
 
Posts: 5
Joined: Mon May 11, 2009 8:59 am

Re: p3 4400 surface mounted chip

Post by chickensandwich »

It continually fades in and out in resonance with the transmitting. I have tried powering up without the zigbee, letting the cap charge and placing the zigbee in and when it transmits the process starts again fading in and out, other then that the KAW works great. The display also shows the no load voltage fluctuating from 119vac-123vac, w/zigbee, and solid 120vac without.

I tested the voltage across the 10k uF cap and the voltage peaks at 2.8vdc and after transmitting the voltage drops to 1.9vdc. I could try a bigger cap. Thank you for the response.

chickensandwich
 
Posts: 5
Joined: Mon May 11, 2009 8:59 am

Re: p3 4400 surface mounted chip

Post by chickensandwich »

I figured it out... After upping the size of the capacitor to 22,000 uF and still having the same problem, I looked at the zigbee with x-ctu and read the parameters. I must have done something wrong when writing to the zigbee in the terminal. I changed them to what they should be, as stated in the instructions but not with the terminal, and the T-A-W is transmitting and the display is solid.

adafruit
 
Posts: 12151
Joined: Thu Apr 06, 2006 4:21 pm

Re: p3 4400 surface mounted chip

Post by adafruit »

yay instructions :)

Locked
Please be positive and constructive with your questions and comments.

Return to “XBee products (discontinued)”