picoSam 32

The picoSam 32 is a very low tech data sampler. It's maximum sampling speed is something like 100.000 samples per second. Probably lower, depending on the operating system driving it.

In theory this could be called a 100 kHz oscilloscope. And since it is digital, this could be called a 100 ksps DSO (Digital Storage Oscilloscope). I prefer to call it a sampler. It takes digital samples of the real world. And since it bridges the gap between your valuable computer and the harsh environment which we, humans, need to have a pleasurable life, it has full isolation between both sides. It takes more than a simple wrong connection to fry your computer.

The features of picoSam 32

two seperate sections that communicate via opto couplers
one power supply with a DC/DC converter
affordable ADC (analog to digital converter) with one or two channels
integrators with 5 Volt clmaps on both ADC inputs
LED indicators on all ADC signal lines
operates on AC, DC or battery power
available as PCB only, parts kit or fully assembled
RIA Springcon 'no tools required' terminal blocks

No picture yet. The PCB's are being manufactured at this moment.

Some picoSam 32 features:

Safe design: full isolation between PC and real world
- DC/DC converter isolates power supplies
- Opto couplers isolate digital signals
- ADC operates in real world only
- Analog inputs protected by zener diodes
Inexpensive ADC and opto couplers
Buffering of digital signals
LED indicators on all control lines to and from the ADC:
- CS = chip select
- DI = data to program the ADC
- DO = conversion results from ADC
- CLK = clock pulse to sync DI and DO signals
Integrators on ADC inputs
Adjustable power supply on ADC side (to calibrate ADC)

This makes the picoSam 32 interesting for those people who would like to do some real programming. Do something useful while trying to master the (black) art of programming. First get the LED's blinking. Then get the ADC to turn voltages into numbers. Then get the numbers in a graph and export them to a database or spreadsheet.

Control freaks will also like this design. It is a safe way to record what's going on in their world. This circuit will run on any kind of computer. Hook up that old dodo computer and have the set record power line voltages, thermostat signals, weather data, indoor gas levels, battery conditions, you name it. For a few euro's you get a fast datalogger with unlimited memory and all the features you have been longing for for decades. Need ethernet? Just plug in a cheap NIC. Need USB? Probably on board already. Need to show data in Hi Res on screen? It's probably there already...

Here is the BOM (Bill Of Materials) for the POES device. The table speaks for itself.

Part	Description	Amount	Price	Total
PCB	Printed Circuit Board	1	10.00	10.00
Caps	Various capacitors	5	0.15	0.75
Elco	Electrolytical capacitor 470 uF	1	0.15	0.15
Diode	Zener diodes, 5.1 Volt, 0.5 Watt	2	0.10	0.20
Rect	Bridge rectifier, round, 1.5 A	1	0.20	0.20
LED	3 mm LED's in different colours	4	0.15	0.60
Volt1	LM 317 adjustable power regulator TO 220	1	0.25	0.25
Volt2	7805 fixed voltage regulator TO 220	1	0.20	0.20
DC/DC	DC to DC converter, 5V in, 9 V out, 1 Watt	1	5.00	5.00
PC 817	Opto coupler, Sharp PC 817	4	0.25	1.00
HC245	74 HCT 245 bus buffer with Schmitt triggers	1	0.25	0.25
ADC	ADC 0832 serial Analog to digital converter, 8 bit	1	2.00	2.00
Conn	RIA springcon wire clamp connectors	2	0.40	0.80
Conn	25 pin sub-D connector, male	1	0.45	0.45
MOSFET	BS 170 small signal N channel MOSFET	1	0.10	0.10
Res	Various resistors	10	0.06	0.60
IC 6	Six pin IC socket, springloaded	4	0.10	0.40
IC 8	Eight pin IC socket, springloaded	1	0.10	0.10
IC 20	Twenty pin IC socket, springloaded	1	0.10	0.10
Potm	20 turn potentiometer 1 k	1	0.60	0.60
Total parts				23.75
Mfg	Labour : design, assembling and testing			11.25
Grand total				35.00

You can buy the LM 0832 directly at Texas Instruments for free by requesting a sample. At TI it is called the TLC 0832. Possibly other companies also allow you to sample the chip.

The picoSam 32 and it's brothers, sisters and orphans live happily together in the PicoSampler section, elsewhere on Fruttenboel.

Page created on 9 February 2008 and

Page equipped with FroogleBuster technology