hi every one
my new project is to make a bigger temperature led scale using a
0.56 " Digital Display Red LED item from ebay


http://www.ebay.co.uk/itm/190898617176?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
problem i have is that i was going to use an uln2803 for the second set of led's but looking at the schematic of the segment led it it's outputs are 3 vcc and the rest is -vcc the uln2803 works on a + not a - so what chip could i use to make this work
cheers
marko

 

hi every one
my new project is to make a bigger temperature led scale using a
0.56 " Digital Display Red LED item from ebay


http://www.ebay.co.uk/itm/190898617176?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
problem i have is that i was going to use an uln2803 for the second set of led's but looking at the schematic of the segment led it it's outputs are 3 vcc and the rest is -vcc the uln2803 works on a + not a - so what chip could i use to make this work
cheers
marko

The item you linked to is a complete temperature module. It has its own thermistor sensor and its own display. There is nothing to build; just connect power and ground and it works.

 

i want to make a bigger one using led strips

 

i want to make a bigger one using led strips

Then you need an electrical design. The design will need to include a temperature sensor (thermistor, or IC like the LM34), a means of converting the sensor output to a usable format, a display driver, and a display.