.
Each year, more people are killed by lighting than by most other natural hazards, including hurricanes and tornadoes. No wonder, then, that lightning protection agencies have described the danger of lightning as "underrated". This Lightning Sentinel (my own design -- click on it to enlarge) was tested over a period of a year and a half. In most cases, it picked up the possibility of a thunderstorm well in advance of any thunder or lightning on the horizon. In its simplest form (see Figure 1) the Lightning Sentinel illuminates a green LED when atmospheric charge lies within normal limits, and a red LED when this rises to a risk level. Figure 2 shows how a 5V relay may be added, so that the circuit may be put to more serious use, e.g. triggering a siren. The Lightning Sentinel may also be used as a monitor of atmospheric charge, and this may yield very interesting results. The charge is presented at point C (Figure 1) as a fluctuating voltage. The "engine room" of the circuit is comparator IC1a, which includes an Antenna and an Earth. Note therefore that the circuit is ground referenced (to Earth), since one is measuring the potential difference between the atmosphere and the earth. IC1a is followed by comparator IC1b, which compares the potential (voltage) at IC1a pin 1 with the fixed potential presented to IC1b pin 6. R2 is initially wired in parallel with R4 to present a lower potential at input pin 6, and is used to calibrate the Lightning Sentinel, through VR1, to the daily minimum charge (which lies between the illumination of the red and green LEDs). This minimum charge is estimated over a week or two. Once calibration is complete, one terminal of R2 is snipped as shown in circuit diagram Fig. 1, and the Lightning Sentinel is ready for long-term service. VR1 is a multi-turn preset. The Lightning Sentinel draws about 10mA current on standby, and is ideally powered by a regulated DC plug-pack power supply between 6V and 35V. See Atmospheric Monitor [2] for the design of the aerial. OBSERVATION: In my view, this is about the most interesting thing one can do with electronics apart from radio and metal detecting. This represents my first (until now) unpublished design in a long time. I know several people who were narrowly missed by lightning, including my late wife Mirjam, who was missed by about four metres / yards.
Each year, more people are killed by lighting than by most other natural hazards, including hurricanes and tornadoes. No wonder, then, that lightning protection agencies have described the danger of lightning as "underrated". This Lightning Sentinel (my own design -- click on it to enlarge) was tested over a period of a year and a half. In most cases, it picked up the possibility of a thunderstorm well in advance of any thunder or lightning on the horizon. In its simplest form (see Figure 1) the Lightning Sentinel illuminates a green LED when atmospheric charge lies within normal limits, and a red LED when this rises to a risk level. Figure 2 shows how a 5V relay may be added, so that the circuit may be put to more serious use, e.g. triggering a siren. The Lightning Sentinel may also be used as a monitor of atmospheric charge, and this may yield very interesting results. The charge is presented at point C (Figure 1) as a fluctuating voltage. The "engine room" of the circuit is comparator IC1a, which includes an Antenna and an Earth. Note therefore that the circuit is ground referenced (to Earth), since one is measuring the potential difference between the atmosphere and the earth. IC1a is followed by comparator IC1b, which compares the potential (voltage) at IC1a pin 1 with the fixed potential presented to IC1b pin 6. R2 is initially wired in parallel with R4 to present a lower potential at input pin 6, and is used to calibrate the Lightning Sentinel, through VR1, to the daily minimum charge (which lies between the illumination of the red and green LEDs). This minimum charge is estimated over a week or two. Once calibration is complete, one terminal of R2 is snipped as shown in circuit diagram Fig. 1, and the Lightning Sentinel is ready for long-term service. VR1 is a multi-turn preset. The Lightning Sentinel draws about 10mA current on standby, and is ideally powered by a regulated DC plug-pack power supply between 6V and 35V. See Atmospheric Monitor [2] for the design of the aerial. OBSERVATION: In my view, this is about the most interesting thing one can do with electronics apart from radio and metal detecting. This represents my first (until now) unpublished design in a long time. I know several people who were narrowly missed by lightning, including my late wife Mirjam, who was missed by about four metres / yards.
No comments:
Post a Comment