Voodoo Main Discussion

[surfdetector]

Is there any where else fellow members would cut corners, or splurge on better parts?

You would save significantly if you purchased the majority of the parts from Tayda. The price point on the screw terminals alone is worth it.
Cheers

[dingbatca]

Updated to the known working XTAL. Got plenty of plain pin header lying around the house. OUCH! those screw terminals are expensive. Might just stick with simple pin headers. My current BOM is at $58, PDF is attached. I re-worked the capacitors and resistors so save a bit, and have in-stock parts.

Is there any where else fellow members would cut corners, or splurge on better parts?

[waltr]

dingbatca,
The XTAL I used is Mouser #520-ECS200-18-4X-CKM
The pn 815-ABL-20-B1U you listed should also work.

surfdetector posted the FQT7N19 MOSFET number

For 0.1" pins and header I buy 517-929974-01-36-RK & 517-9611366404AR, then cut them to number of pins needed.

Resistors are 1/4W, 0.3" long body so bent leads are 0.4" to PCB pads.
100k trim pot 229-CT-9EW104 is correct size.

I also like those screw terminals and just found them in Mouser, pn 651-1725656.

For the four push button I soldered on straight pins but then found the LCB interfered with mating header.
I'm going to replace them with right angle pins like these: 649-1012937990904BLF

I think you are good to go.

[surfdetector]

Thanks for the part number 512-FQT7N10LTF. The fact they were SMD was throwing me off. Still hunting for 2/3-pin 100th pin headers on Mouser.

571-9-146278-0 Mouser
These are breakaway so you can snap them to what size you want

[dingbatca]

Thanks for the part number 512-FQT7N10LTF. The fact they were SMD was throwing me off. Still hunting for 2/3-pin 100th pin headers on Mouser.

Videos helped, thanks for posting those. I love the use of screw terminal connection you did on the more static connections, like the coil. What's the pitch?

I also added a few sockets to my cart.
6X 571-1-2199298-2
1X 571-1-2199298-4
1X 571-1-2199299-5

[surfdetector]

Just building up my BOM and I would much appreciate the groups wisdom on what parts I should, or should not use. I have a large portion of this stuff in the shop, but for the sake of completeness, I am trying to get everything documented. I have included the corresponding Mouser part numbers.

I know I need help with the FQT7N10 mosfet and the 2/3-pin 100th pitch headers. I know there was some chatter earlier on about the correct crystal. Did I get that right?

My goal is to use quality parts, that have the correct pitch, and are not total overkill. I must admit, all gold sockets are nice, but I am going for a good balance of cost and performance.

Thanks!

Here are a couple of part numbers:
512-FQT7N10LTF Mouser
A-197 Tayda
A-236 Tayda

I did a series of build videos for this project:

https://youtube.com/playlist?list=PLgBlcFVgN7pTgYK7McUNy2u3m-SRFjPFy

[dingbatca]

Just building up my BOM and I would much appreciate the groups wisdom on what parts I should, or should not use. I have a large portion of this stuff in the shop, but for the sake of completeness, I am trying to get everything documented. I have included the corresponding Mouser part numbers.

I know I need help with the FQT7N10 mosfet and the 2/3-pin 100th pitch headers. I know there was some chatter earlier on about the correct crystal. Did I get that right?

My goal is to use quality parts, that have the correct pitch, and are not total overkill. I must admit, all gold sockets are nice, but I am going for a good balance of cost and performance.

Thanks!

Componet	Location on PCB	Quanty	Mouser #
16x2 LCD Module	U4	1	763-0216BZ-RN-YBW
78L05 +5V regulator	U7	1	595-UA78L05CLPR
79L05 -5V regulator	U6	1	595-MC79L05ACLPR
4066BP bilateral switches	U5	1	595-SN74HC4066N
LT1054 voltage converter	U8	1	584-LT1054CN8#PBF
NE555 timer	U11	1	595-NE555P
NE5532 dual opamp	U3	1	595-NE5532P
PIC18F4520 microcontroller	U2	1	579-PIC18F4520-I/P
TL071 single opamp	U1	1	595-TL071CP
TL072 dual opamp	U9-10	2	595-TL072CP
1N4148	D2-7	6	512-1N4148
MUR460	D1	1	863-MUR460RLG
1μF	C15-18, C33	5	581-SR215E105MARAP2
4n7	C19-20, C24	3	80-C322C472F1G
10nF	C25, C30	2	80-MMK5103J50J01L4
22pF	C2, C4	2	81-RDE5C2J220J2M1H3A
22μF electrolytic	C8, C28	2	667-50SEK22M
47μF electrolytic	C3, C6, C9	3	80-A759KS476M1KAAE45
100nF	C5, C7, C22-23, C26-27, C31, C34-35	9	80-R82DC3100AA50K
100μF electrolytic	C13-14, C29, C32	4	80-A750BK107M1AAAE24
470nF	C10-12	3	581-SR215E474ZARTR2
1000μF electrolytic	C1, C21	2	80-A750MV108M1EAAE14
2N3904 NPN	Q2, Q4, Q6-8, Q10, Q12	7	583-2N3904
2N3906 PNP	Q3, Q5, Q9	3	512-2N3906BU
FQT7N10 mosfet	Q11, Q13	2	HELP!
IRF840 mosfet	Q1	1	844-IRF840LCPBF
2-pin 100th pitch	PL1-6, PL10-13	10	Help
3-pin 100th pitch	PL7-8	2	Help
5-pin ICSP	PL9	1	bulk pin headders
1k	R8, R19, R25, R37 R57, R62	6	603-MFR-25FBF52-1K
1M	R18, R58, R63-64	4	603-MFR-25FBF52-1M
1R0	R6, R53	2	603-MFR-25FBF52-1R
2M2	R52, R54-55	3	603-MFR-25FBF52-2M2
3R3 2W	R2	1	603-RSF200JT-73-3R3
5k1	R15	1	603-MFR-25FBF52-5K1
10k multi-turn trimmer	R41	1	229-CT-9EW103
10k	R1, R3-5, R7, R9-13, R23, R26, R28, R33- 36, R39-40, R42-43, R45, R49-50, R56, R60-61, R67	28	603-MFR-25FBF52-10K
12k	R68	1	603-MFR-25FBF52-12K
20k	R24, R48	2	603-MFR-25FBF52-20K
22k	R27, R31, R44, R46-47, R51, R59, R65	8	603-MFR-25FBF52-22K
27R	R17, R32	2	603-MFR-25FBF52-27R
33k	R14, R20	2	603-MFR-25FBF52-33K
33R	R66	1	603-MFR-25FBF52-33R
100k multi-turn trimmer	R22, R30	2	229-CT-9EW104
100k	R16, R21, R29	3	603-MFR-25FBF52-100K
100R	R38	1	603-MFR-25FBF52-100R
20MHz crystal	XTAL1	1	815-ABL-20-B1U

[6666]

Its fairly easy if you have a Pmos, ground is the negative battery plate,
if you have a Nmos ground is positive battery plate.
If you have a a virtual ground (or virtual earth) then thats a little different,
usually made from a couple of resisters or an op amp with the node as ground.

Whats being proposed with the current limiting is a simple 12 volt globe in series with the load powered from the 12 volt side of the power supply which is isolated from the mains.
I just use an 8 pack of nicads.

To be clearer Pmos TX and Nmos TX.
We really need more time to edit thanks.

[Matt_Rowe]

Im using 12 cells at 16 volts then stepping it down. Because with 3 cells you only use around 30% of the battery. With 4 you use around 40% of the battery. Minus the little you use in the converter.

just use one of these, and reverse the center or end one, so you get 12 volts, youll want 2 negs and 1 pos on one end.


J $2.69 with free shipping from ebay

[6666]

Its fairly easy if you have a Pmos, ground is the negative battery plate,
if you have a Nmos ground is positive battery plate.
If you have a a virtual ground (or virtual earth) then thats a little different,
usually made from a couple of resisters or an op amp with the node as ground.

Whats being proposed with the current limiting is a simple 12 volt globe in series with the load powered from the 12 volt side of the power supply which is isolated from the mains.
I just use an 8 pack of nicads.

[6666]

Not to show my age... but I remember when our automobile electrical systems was 6V, POSITIVE ground!

Yep same here in Oz.

[KingJL]

theres actually quite a few instances especially in the marine industry and boating where Positive grounded systems are the norm. Also especially on some vehicles.

Not to show my age... but I remember when our automobile electrical systems was 6V, POSITIVE ground!

[Matt_Rowe]

Ok i will hunt down a 40 watt bulb. Ill order the bms also and the converter.

this is how to build a house supply current limiter, for just a few dollars,the plug on the right side of picture is just a standard 2 socket you use in a wall. the light buld could be 20 watt night light, and the light socket is the clay one that gets used in closets, 20 watt still be to much in a MD circuit

[Matt_Rowe]

Ill just order the 4s and the converter and isolate it from the house ground no biggie i can move around with the detector then anyway ok thank you very much guys much appreciated

you have to use a power supply not connected to your house at all, unless you dont use the neutral or ground, when you have a house current any extra that the device is not using flows back through the neutral wire, back to the utility, and the neutral wire is connected to ground at the service panel.
So you can have current flowing in reverse through your neutral wire into your ground, that is why us electricians always make sure the breaker is turned off before we work on a circuit,In our line of work, the neutral wire is also called a common wire, its named common because its the common test point for all circuits since all neutrals are connected in a house, and neutral gets connected to ground, so actually ground can basically be called a common wire

[Matt_Rowe]

Bizzaro world where the positive of a battery is the ground

theres actually quite a few instances especially in the marine industry and boating where Positive grounded systems are the norm. Also especially on some vehicles.