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lab:pigi:hardware [2013-07-23 20:16] – [Prototype/Production costs] chronolab:pigi:hardware [2023-04-19 13:56] (current) – [High Voltage] chrono
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 ====== PiGI Hardware ====== ====== PiGI Hardware ======
  
-**Schematic**+**Schematic V1.1**
  
 {{:lab:pigi-raspberry-pi-geiger-mueller-counter-schematics-v1.1.png|}} {{:lab:pigi-raspberry-pi-geiger-mueller-counter-schematics-v1.1.png|}}
 ~~CL~~ ~~CL~~
  
-**Layout**+**Layout V1.1**
  
 {{:lab:pigi-raspberry-pi-geiger-mueller-counter-board-top-v1.1.png?215|}} {{:lab:pigi-raspberry-pi-geiger-mueller-counter-board-top-v1.1.png?215|}}
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 {{:lab:pigi-raspberry-pi-geiger-mueller-counter-board-v1.1.png?215|}} {{:lab:pigi-raspberry-pi-geiger-mueller-counter-board-v1.1.png?215|}}
  
-**Prototype PCB's**+**Prototype PCB's V1.0**
  
 {{:lab:pigi-prototype-board-v1.0-pcb-only.jpg|}} {{:lab:pigi-prototype-board-v1.0-pcb-only.jpg|}}
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 | T1 | NPN transistor with a >=1kV collector-emitter breakdown voltage | [[https://mouser.com/Search/ProductDetail.aspx?R=STN0214virtualkey51120000virtualkey511-STN0214|STN0214]] | | T1 | NPN transistor with a >=1kV collector-emitter breakdown voltage | [[https://mouser.com/Search/ProductDetail.aspx?R=STN0214virtualkey51120000virtualkey511-STN0214|STN0214]] |
  
-The inductor is a high Q wound dust core choke with shielding to minimize EMI. The output voltage is set by the maximum current, which is controlled by the adjustable trimmer (R10) in the emitter lead of the STN0214. A lower resistor value (turning CCW) wil result in higher output voltage. Alternatively, when only a certain type of GMT is going to be used with a PiGI module, R10 can be replaced with R10a to set the specific required voltage for the GMT. Please add working values for R10(a) with your particular tube to the [[lab:pigi:common-geiger-tube-parameter]].+The inductor is a high Q wound dust core choke with shielding to minimize EMI. The output voltage is set by the maximum current, which is controlled by the adjustable trimmer (R10) in the emitter lead of the STN0214. A lower resistor value (turning CCW) will result in higher output voltage. Alternatively, when only a certain type of GMT is going to be used with a PiGI module, R10 can be replaced with R10a to set the specific required voltage for the GMT. Please add working values for R10(a) with your particular tube to the [[lab:pigi:common-geiger-tube-parameter]].
  
 Based on the CMOS 555 Based on the CMOS 555
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-===== Prototype/Production costs =====+===== Prototype & projected production costs =====
  
 |< 100% >| |< 100% >|
 ^ Volume ^ PCB ^ Parts ^ Soldering method ^ Risk margin ^ Final product ^ ^ Volume ^ PCB ^ Parts ^ Soldering method ^ Risk margin ^ Final product ^
 | 7 V1.0 Prototypes | EUR 7,23 | EUR 8,67 | Hand (EUR 0) |  ---  | EUR 15,90 | | 7 V1.0 Prototypes | EUR 7,23 | EUR 8,67 | Hand (EUR 0) |  ---  | EUR 15,90 |
-| < 100 V1.1 | EUR | EUR 9,70 | Hand (EUR 0) |  20%  | TBD | +| < 100 V1.1 | EUR 4,97 | EUR 9,70 | Hand (EUR 0) |  20%  | TBD | 
-| >= 100 V1.1 | EUR | EUR 7,05 | Outsourcing (TBD) |  15%   | TBD | +| >= 100 V1.1 | EUR 2,79 | EUR 7,05 | Outsourcing (TBD) |  15%   | TBD | 
-| >= 1000 V1.1 | EUR | EUR 3,95 | Outsourcing (TBD) |  10%  | TBD  |+| >= 1000 V1.1 | EUR 0,70 | EUR 3,95 | Outsourcing (TBD) |  10%  | TBD | 
 + 
 +As we can see, it scales very well with numbers and a non-profit oriented production run could bring many modules to people for less than 20 EUR. If it were sold for more than 25 EUR (fully assembled), someone would really be ripping people off.
 ===== Assembly Instructions ===== ===== Assembly Instructions =====
  
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 === Bottom === === Bottom ===
  
-|< 100% 5% 15% 60% 20% >| +|< 100% 5% 8% 8% 59% 20% >| 
-^  #  ^ ID ^ Part/Value ^  Package  ^ +^  #  ^  V1.0  ^  V1.1  ^ Part/Value ^  Package  ^ 
-|  1  | D2 | MMSD4148 | | +|  1  |  D2  || MMSD4148 | | 
-|  2  | C4 | 1nF |  0805  |  +|  2  |  C4  || 1nF |  0805  |  
-|  3  | R5 | 330 ohms |  0805  | +|  3  |  R5  || 330 ohms |  0805  | 
-|  4  | R4 (R1 V1.0) | 100k |  0805  | +|  4  |  R1  |  R4  | 100k |  0805  | 
-|  5  | R6 | 220k |  0805  | +|  5  |  R6  || 220k |  0805  | 
-|  6  | R1 (R4 V1.0)| 1k |  0805  | +|  6  |  R4  |  R1  | 1k |  0805  | 
-|  7  | R9 | 27k |  0805  | +|  7  |  R9  || 27k |  0805  | 
-|  8  | IC1 | TLC555QDRQ1 - Case mark facing towards R6 |  SOIC-8  | +|  8  |  IC1  || TLC555QDRQ1 - Case mark facing towards R6 |  SOIC-8  | 
-|  9  | T2 | MMBT4401 |  SOT-23  |+|  9  |  T2  || MMBT4401 |  SOT-23  |
  
 If you're not stacking two modules use either a 0-ohm resistor/solder-bridge on J1 or a capacitor to connect the GPIO Pin of the PI to the inverter's collector. Don't use a capacitor when connecting to a uC with internal pull-up (like a Raspberry Pi). If you're not stacking two modules use either a 0-ohm resistor/solder-bridge on J1 or a capacitor to connect the GPIO Pin of the PI to the inverter's collector. Don't use a capacitor when connecting to a uC with internal pull-up (like a Raspberry Pi).
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 === Top === === Top ===
  
-|< 100% 5% 15% 60% 20% >| +|< 100% 5% 8% 8% 59% 20% >| 
-^  #  ^ ID ^ Part/Value ^  Package  ^ +^  #  ^  V1.0  ^  V1.1  ^ Part/Value ^  Package  ^ 
-|  1  | C5 | 330pF |  0805  | +|  1  |  C5  || 330pF |  0805  | 
-|  2  | R7 | 1.5k |  0805  | +|  2  |  R7  || 1.5k |  0805  | 
-|  3  | R8 | 100k (default - see circuit description for other values) |  0805  | +|  3  |  R8  || 100k (default - see [[#signals]] for other values) |  0805  | 
-|  4  | T3 | MMBT4401 |  SOT-23  | +|  4  |  T3  || MMBT4401 |  SOT-23  | 
-|  5  | C1 | 220uF/10 |  see BRD  | +|  5  |  C1  || 220uF/10V LowESR Aluminium Electrolytic Capacitor |  see BRD  | 
-|  6  | C2 | Vishay MLCC 10nF/1kV |  1206  | +|  6  |  C2  || Vishay MLCC 10nF/1kV |  1206  | 
-|  7  | C3 | Vishay MLCC 10nF/1kV |  1206  | +|  7  |  C3  || Vishay MLCC 10nF/1kV |  1206  | 
-|  8  | R2 | KOA Thick Film 1M 0.25W 0.5% |  1206  | +|  8  |  R2  || KOA Thick Film 1M 0.25W 0.5% |  1206  | 
-|  9  | R3 | KOA Thick Film 4.7M 0.25W 1% |  1206  | +|  9  |  R3  || KOA Thick Film 4.7M 0.25W 1% |  1206  | 
-|  10  | D1 | Vishay BYGM23 Fast Recovery Diode 1.5A/1000V/75ns |  DO-214AC (SMA)  | +|  10  |  D1  || Vishay BYGM23 Fast Recovery Diode 1.5A/1000V/75ns |  DO-214AC (SMA)  | 
-|  11  | T1 | STN0214 Bipolar NPN 1k2V |  SOT-223  | +|  11  |  T1  || STN0214 Bipolar NPN 1k2V |  SOT-223  | 
-|  12  | L1 | Murata Shielded Inductor 15mH |  see BRD  | +|  12  |  L1  || Murata Shielded Inductor 15mH |  see BRD  | 
-|  13  | R10 | Bourns Trimmer 100R |  see BRD  | +|  13  |  R10  || Bourns Trimmer 100R |  see BRD  | 
-|  *  | R10a | optional, with a fixed value instead of R10 |  0805  | +|  *  |  ---  |  R10a  | optional, with a fixed value instead of R10 |  0805  | 
-|  14  | H1 | [[http://www.adafruit.com/products/1112|Stacking Raspberry Pi Header]] |  2x13 2.54mm  |+|  14  |  H1  || [[http://www.adafruit.com/products/1112|Stacking Raspberry Pi Header]] |  2x13 2.54mm  |
 ===== Test Points ===== ===== Test Points =====
  
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 | 10M (Fluke-87V internal resistor) | 230V | 230V | | 10M (Fluke-87V internal resistor) | 230V | 230V |
 | 10M + 42.3M (9x 4.7MOhm in series) | 63.7V | 333V | | 10M + 42.3M (9x 4.7MOhm in series) | 63.7V | 333V |
-| 10M + 1G ([[http://www.highvoltageshop.com/shop/article_RES_20kV_1G/Hochspannungswiderstand-20kV-1-GigaOhm-Messwiderstand%2C-Entladewiderstand.html|20kV 1 GigaOhm single resistor]]) | 4.56V | 460V |+| 10M + 1G ([[http://highvoltageshop.com/epages/b73088c0-9f9a-4230-9ffc-4fd5c619abc4.sf/de_DE/?ObjectPath=/Shops/b73088c0-9f9a-4230-9ffc-4fd5c619abc4/Products/RES_20kV_1G|20kV 1 GigaOhm single resistor]]) | 4.56V | 460V |
  
 Measured at: [+] Cathode of D1 (pin facing towards R2) [-] Cathode of GM Tube (HV- Pad) Measured at: [+] Cathode of D1 (pin facing towards R2) [-] Cathode of GM Tube (HV- Pad)
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 **Formula** **Formula**
  
-<x>+<m>
 V_actual = V_read * {{ R_meter + R_probe } / R_meter} V_actual = V_read * {{ R_meter + R_probe } / R_meter}
-</x>+</m>
  
 **Examples** **Examples**
  
-<x>+<m>
 63.7V * {{10 MOhm + 42.3 MOhm} / {10 MOhm}} \approx 333V  63.7V * {{10 MOhm + 42.3 MOhm} / {10 MOhm}} \approx 333V 
-</x>+</m>
  
-<x>+<m>
 4.56V * {{10 MOhm + 1000 MOhm} / {10 MOhm}} \approx 460V  4.56V * {{10 MOhm + 1000 MOhm} / {10 MOhm}} \approx 460V 
-</x>+</m>
  
  
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 For optimal tube operation R3 (anode resistor) and the equivalent of R7/R8 (cathode resistor) For optimal tube operation R3 (anode resistor) and the equivalent of R7/R8 (cathode resistor)
-should have a 45:1 Ratio, at least that seems to have become "industry standard". A short test with the LND712 GMT showed that indeed the signal flanks became a bit more precise when R8 is 220k instead of 100k in order to match the 10M for LND 712. However, in many tests, the circuit has shown a very high resilience against "suboptimal" operating conditions, so the LND712 counted fine, even with "just" 100k. +should have a 45:1 Ratio, at least that seems to have become "industry standard". A short test with the LND712 GMT showed that indeed the signal flanks became a bit more precise when R8 is 220k instead of 100k in order to match the 10M for LND 712. However, in many other tests the circuit has shown a very high resilience against "suboptimal" operating conditions.
  
-** Suboptimal **+** Worst Scenario (Undervoltage & very high anode/cathode resistor ratio mismatch) **
  
 {{:lab:pi-gi-v1.0-dso-tubecathode-bad-50mv-50us.png|}} {{:lab:pi-gi-v1.0-dso-tubecathode-bad-50mv-50us.png|}}
  
-** Optimal **+** Recommended operating voltage & 45:1 anode/cathode resistor ratio **
  
 {{:lab:pi-gi-v1.0-dso-tubecathode-good-50mv-50us.png|}} {{:lab:pi-gi-v1.0-dso-tubecathode-good-50mv-50us.png|}}
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 === GPIO output === === GPIO output ===
 +
 +This is how the final impulse signal looks like to the counting IO Pin. It also leaves a question: For the LND 712 the dead-time is supposed to be 90us, but when you count the divs in the scopeshot above it is about 140us. Shouldn't in this case 140us be used as a base value for the [[lab:pigi:software|dead-time algorithm]]?
  
 {{:lab:pi-gi-v1.0-dso-gpio-output-0.5v-20us.png|DSO Trace of the falling edge on the GPIO Line}} {{:lab:pi-gi-v1.0-dso-gpio-output-0.5v-20us.png|DSO Trace of the falling edge on the GPIO Line}}
- 
-<WRAP round help> 
-This is how the final impulse signal looks like to the counting IO Pin. It also leaves a question: For the LND 712 the dead-time is supposed to be 90us, but when you count the divs in the scopeshot above it is about 160us. Shouldn't in this case 160us be used as a base value for the [[lab:pigi:software|dead-time algorithm]]? 
-</WRAP> 
  
 ===== Radioactive Test Sources ===== ===== Radioactive Test Sources =====
  
-Since everything is regulated these days up to the point that only multi-national-companies can obtain the stuff they need to develop something it's quite a challenge to find sources to test your Geiger Counter with more than just the local dose rate. +Since everything is over-regulated these days, up to the point where only multi-national-corporations can obtain the resources needed to develop something easily, it's quite a challenge to find radioactive test sources to probe a Geiger Counter with more than just the local dose rate. So instead of having simple access to quality test-radiators which can be handled and stored in a safe manner, we have to improvise and hack something out of whatever we can find. When we consider that the regulation's original intent has to protect of people from harm, it backfired pretty well. 
  
 The mightyohm blog has compiled a list of things you can try to use:  The mightyohm blog has compiled a list of things you can try to use: 
Trace:

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