Please Be Discrete

January 20, 2011 by · 1 Comment
Filed under: Projects 

The 555contest has triggered (pun!)  a desire to be discrete. No, im not talking about conservative speech or keeping secrets, im talking individual componants!

It looks like im not alone! Someone has already been looking into this on Dave Jones’s eevblog

The forum user has linked to a schematic which may have been used to digitaly simulate the inner workings of the 555 timer.

I recall using a tool called (Circuit builder?) in high school to design basic digital/analog circuits. I wonder if i still have it installed on an old laptop somewhere…

My goals:
Reverse engineer the inner workings of a 555 timer chip.
Build a functioning 555 timer chip with “socket” extension that can be plugged into various “test boards”.
Make 2-3 test boards (blinky lights, pwm controller, one shot/debounce)
Design and etch clean looking boards for the 555 and test boards

Simulation software (circuit builder, pspice or lt spice)
Circuit board design software (eagle)

Linear Technology LTspice IV …examples\Educational\NE555.asc

Parts list (potential):
Transistors: BC847B (NPN ones) and BC857B (PNP ones)
Q1 N5 5 N7 1 NP
Q2 N1 6 N6 1 NP
Q3 N1 N6 N8 1 NP
Q4 N5 N7 N8 1 NP
Q5 7 N16 1 1 NP
Q6 N17 N14 1 1 NP
Q7 N1 N1 N3 1 PN
Q8 N17 N1 N2 1 PN
Q9 1 N5 N2 1 PN
Q10 N5 N5 N4 1 PN
Q11 N11 N20 N9 1 PN
R1 8 N3 4.7K
R2 8 N2 830
R3 8 N4 4.7K
R4 8 N9 1K
R5 8 5 5K
R6 8 N22 6.8K
Q13 1 2 N10 1 PN
Q14 N14 N10 N11 1 PN
Q15 N13 N12 N11 1 PN
Q16 N13 N15 N12 1 PN
R7 N14 1 100K
R8 N13 1 100K
R9 N15 5 5K
R10 N15 1 5K
R11 N8 1 10K
Q17 N16 4 N18 1 PN
Q18 N19 N17 1 1 NP
R12 N18 N20 5K
Q19 N20 N20 8 1 PN
Q20 N21 N20 8 1 PN
Q21 N21 N19 1 1 NP
R13 N17 N21 4.7K
Q22 8 N22 N23 1 NP
Q23 N22 N21 N24 1 NP
Q24 8 N23 3 1 NP
R14 3 N23 3.9K
Q25 3 N25 1 1 NP
R15 N25 N24 220
R16 1 N24 4.7K
R17 N24 N16 10K
D2 3 N22 D
D1 N18 N19 D
.MODEL NP NPN(BF=125 Cje=.5p Cjc=.5p Rb=500)
.MODEL PN LPNP(BF=25 Cje=.3p Cjc=1.5p Rb=250)
.MODEL D D(Is=1e-12 Cjo=1p Rs=5

to be updated as the project procedes!

555 Challenge

January 19, 2011 by · Leave a Comment
Filed under: Blog 

Twitter is alive with excitement over the 555 Timer. Jeri Ellsworth (twitter) has sparked an interest in this 40 year old IC.  With the help of Chris Gammell and some fellow hackers and engineers , She has proposed a design challenge contest revolving around this simple timer/multivibrator 8 pin dip.

Details are still forming, and are available on Twitter rumors (tumors?) indicate that element14, digikey and designspark are interested in sponsoring this contest.

pick up yours today!
Digikey ( DIP , SMT )
Talonix (High Temp Ceramic!)
Electronicplus (Metal TO-5 package – search for 555can)

Arduino – Displays

January 18, 2011 by · Comments Off on Arduino – Displays
Filed under: Arduino, Projects 

Picked up my first display for my Arduino Duemilanove.

I saw an article over on HackaDay and it reminded me of a previous submission related to a custom job done up overseas in a VW TDI  to monitor various bits, mounted inside a dash button!

Owning a VW TDI, and wanting to monitor EGT, boost, temps, etc motivated me to at least investigate how difficult it is to interface the Arduino with a full color RGB LCD.

After a quick Google search  for “RGB LCD Shield for Arduino”,  I ran across the following product from NKC Electronics.

65k RGB LCD Shield from NKC Electronics - KIT

After a little playing I got the board soldered up and displaying the demo images and some custom text. The arduino demo code library was written by Henning Karlsen for NKC, and is released under the GNU Lesser General Public License. Really easy to assemble, and well documented code.

I did have a little bit of difficulty getting the full Demo code to run, but the bitmap code worked great with a simple upload.

Im sorry Dave… Im afraid I can’t do that.

January 18, 2011 by · Leave a Comment
Filed under: Uncategorized 

Thanks to Dave, for the tweaked revolution-code-blue theme.

New Site Up, Powered by WordPress. Woo.

January 18, 2011 by · Leave a Comment
Filed under: Uncategorized