SALE SIGN not finished yet


Senior Member
Hello to my friends (if I have any)
I am starting this thread for my new sale sign I built but I needed it done sooner then time allowed so I haven't put the picaxe chip 20m2 in it yet.(to make it flash all cool)
I router 'd each display and drilled holes in the back for wires the letters are about 8 inches tall each arrow is separate with a switch to choose which way to point
sale sign schematic full.jpgboard2.jpg

I got the large digital displays off ebay and parts from my garage. I just hooked up the digits with 650 ohm resistors and placed my cheap harbor freight battery to it (only one)
It lights up perfectly in the garage but when you bring out in the sun you can't see shh crap unless you shove you nose to one of the digits so I call it in testing stage. I am planning on getting tinted plexiglass
and holding it out 6 inches from the displays then in theory it should light up beautiful. I tested on one HF garbage battery with presumable 90% charge the sign full lit lasted a staggering 2 hours.
After the sign lights went out I put the battery on the charger again and the power supply that comes with the harbor freight rechargeable drill almost got hot enough to burn my hand.
If by chance there is a person (simple like me) who would want to duplicate this project I highly recommend you do this project 50 feet from any burnable substance, in other words like poeple
have said on here the battery's SUCK! I do have 1 amp schottky diodes for when i try both batterys and I will post more on my sale sign when I add my chip using a buck converter.
It might be awhile because I work a lot but I should be done with it in a couple weeks - 2 months.

I know I know why use those batterys??:confused: well they kinda work and it cost me nothing plus they are light compared to car battery
Plus its entertaining for me because stuff can go wrong.

Your mistakable friend in North Dakota

PS: I still think 74hc595 ic's are the best and westaust55 code using them is priceless
but nothing comes close to the picaxe 20m2! unless of course your not me :)


Senior Member
Sign Update
The sign digits only work bright enough if you are at night and inside a deep cave! I tried all my two cents to make the sign light brighter so it can be used during daylight hours but failed.
I tried a cover with tinting glass 4 inches out then 16 inches out and made no I just put 24V dc from a power supply to the digits and it was little brighter but nothing to brag about.
so now I am going to make my own digits out of single green leds, like 6 or 8 to a digit so 26 X 6 = 156 leds which i will try running them at 10ma each which ='s 156 MA + chip power etc
and if that don't work ..... then I am going to calmly take my car at 80+ mph and run over it with insurance that the sign is unrepairable.
I will update if it works and or if it don't work and of course i am simple ,slow and stubborn because I am still going to have fun using the harbor freight batterys :)

your misguided delusional friend


Well-known member
Engineering is full of things that don't work! It's your job to find out why they don't work. There's no point in building something else that also might not "work."

LEDs have to have proper current to have proper brightness. Have you determined the current through the LEDs?

You have IRFZ drivers. Are they being driven to saturation so the LEDs are getting full available current?

Many things to check before abandoning the project. You'll never learn anything if you always reset when problems show up.


Senior Member
your right texasclodhopper but i'm a plumber which is easy to find a leak but i don't give up easily
the main reason why i work with these chips and my sign etc is because I learn alot (mostly by mistake) but this site and everyones input
helps in endless ways especially when they break it down into simple terms
I will test the digits again and find out exactly what the current is drawning and try to find info on them like max current etc
but knowing my green leds will not fail and are 50 times brighter , its doubtful the ebay red digits will become brighter but its worth a try
plus if i use my single green 3mm leds I can control each one which takes more time but cooler results.


Senior Member
Okay I finally made a new design for sign
I am using 2 buck converters 1 to run the LEDS at 12 vdc and 1 to run the picaxe 20m2 and two 74ch595 with 14 mosfets rfz48n
I got sick of soldering the LEDS so I put them in series of 4 sometimes 5 and I can run them down to 9.4 volts before they start getting dim
the LEDS are flat heads from ebay 5mm
here is short video of the sign working with out batterys hooked to
later if I have time I will draw up a schematic excactly how i made it so you pros can chew me out nicely what errs i made
plus maybe I will add the code too