Pages: 1 [2]   Go Down
Author Topic: Need help with large thermochromic matrix design  (Read 2710 times)
0 Members and 1 Guest are viewing this topic.
United Kingdom
Offline Offline
Newbie
*
Karma: 0
Posts: 43
Some things are difficult, nothing's impossible
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

Out of desperation to get the thing working, I did try the NPNs as per my sketch and used a separate battery supply for the resistor matrix. It does seem to work now, though I really need a single supply fix. I tried a higher supply voltage to avoid the brown-outs, but even though I stopped the Arduino from resetting I still found the shift registers halted while the matrix was connected. Drat!

Yes Grumpy, the column MOSFETs are the TPC6108s as per your project (you can just see them peeking out from the top of the black thermochromic film in one of the photos). They're switched by the 595 shift registers. They're nice and small, don't get hot, and didn't cost the earth.

Really need to figure this supply out...

Best,

Thomas
Logged

Global Moderator
Boston area, metrowest
Offline Offline
Brattain Member
*****
Karma: 545
Posts: 27352
Author of "Arduino for Teens". Available for Design & Build services. Now with Unlimited Eagle board sizes!
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

Where are you located? I thought I posted a link to a 5V, 4A supply that would do the trick for you nicely.
http://www.mpja.com/prodinfo.asp?number=18520+PS , $7
Logged

Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

United Kingdom
Offline Offline
Newbie
*
Karma: 0
Posts: 43
Some things are difficult, nothing's impossible
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

Ah, nice one CrossRoads!

I'm UK-based, but I'm sure I can get myself something similar fairly easily. So, as long as the amps are high enough (>2.5A?) my board won't brown-out?

Sounds too good to be true, but all the advice I've had so far has been solid so I'm not arguing. This'll slash my component count too, as I won't have to use my NPNs on the final board. Fingers crossed.

Best,

Thomas
Logged

Global Moderator
Boston area, metrowest
Offline Offline
Brattain Member
*****
Karma: 545
Posts: 27352
Author of "Arduino for Teens". Available for Design & Build services. Now with Unlimited Eagle board sizes!
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

Thomas,
Update your profile to show location, you'll get better suggestions for sources that way.

You could also use seperate sources while you figure out your current needs.
Logged

Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

United Kingdom
Offline Offline
Newbie
*
Karma: 0
Posts: 43
Some things are difficult, nothing's impossible
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

Done!

I've ordered a local supply to your spec, will try it in a day or two.

Thanks again,

Thomas
Logged

Pages: 1 [2]   Go Up
Jump to: