It is our commitment to provide technology for situations where control is desired. In addition, we hope that our products are used with pleasure and that the user gets familiar with the product. That is why it is our aim to keep our products easy to use and the documentation accessible. But it is unavoidable: we also use terms on the website, in the datasheets and in the manuals that may not be immediately clear to everyone. To explain and maybe to enjoy you, we explain some used “technical terms” in the context of Mobeye products.
A whole series of abbreviations exist for the current wireless communication. The landscape was clear at the introduction of the first mobile phones; we called everything GSM even though we meant 2G and 2,5G. Then UMTS came along, which was actually 3G, and turned out thave a short life time. Fortunately, 2G remained. After that several 4G bandwidths were introduced, a landscape that cannot be explained in one sentence. Even now the world is not ready for all the “layers” in 4G and we are glad … 2G stayed. 5G will arrive soon, despite the discussions. Mobeye ensures that its products are always suitable for the country of use and with the correct communication module. We are also sometimes confused about naming. Shall we just keep the term “GSM” for the whole series of communication modules?
A PIR, as used in the Mobeye i110, Argos or Outdoor Detector, detects moving heat sources; the (fresnel) lens consists of several parts; as soon as the thermal image (infrared radiation) changes, the detector reacts. People, large animals (not insects and spiders), but also drafts and direct sunlight on the lens are noticed. So avoid drafts and direct sunlight. If there has been an unnecessary alarm, change the position of the alarm system or change the sensor sensitivity to “low”.
Jamming is the suppression of wireless signals, by sending a disturbing signal on the same wavelength. Although GSM jammers are only used by a small group of highly professional burglars, they do prohibit the process of sending notifications if they are kept near the device. Mobeye products are alert to this. If a burglar tries to jam, signals the Mobeye alarm system this. As soon as the disturbance has gone, the alarm system will report the alarm as soon as possible, stating that it has been delayed.
When we talk about the inputs of the Mobeye devices, the type of input is relevant. After all, this determines the type of sensor, or rather the sensor’s output signal, that can be connected. Let us try to explain in simple words the difference between inputs for potential-free, digital and analog contacts. We focus on the output signal of the sensor that is connected to the Mobeye input.
A potential-free or voltage-free contact can be connected to “normally open” and “normally closed” inputs. In simple words, the contact switches the input to “open” or “close”. It is important to know if a connected sensor has a voltage-free output. A magnetic contact is a voltage-free switch; a tapped signal from signal indicator will transmit a voltage. The Mobeye NO/NC inputs do accept a limited voltage as potential-free; see the FAQs.
An analog input expects a (limited) input voltage, to be read by the Mobeye circuit board. The voltage values need to be interpreted. For example, a battery voltage gives insight into the condition. For other analog sensors, the voltage first needs to be calculated to other values, such as pressure, humidity, or ammonia content.
A digital (uniwire) input receives signals in zeros and ones. The sensor that sends these signals has prepared the digital signal internally, after measuring an (analogue) value. The digital signal has few disturbances (wireless or wired). After receipt the signal is converted back to a logical value. The digital Mobeye inputs also supply power to the sensor.
Some of the Mobeye devices have an output (“actuator”) to control a device. Some devices have an open collector output, others a relay.
A relay is a type of switch. It is mounted on the printed circuit board, but forms its own (galvanically separated) circuit. Internally it has a coil, electromagnet and a circuit. The circuit has two states, “open” and “closed”. The Mobeye device can apply a voltage to the relay, for example after an alarm or an incoming command. The coil then generates a magnetic field, which causes the circuit to change the state. An external device connected to the relay uses this state “open” or “closed”. This allows it to be activated or deactivated. No voltage comes from the relay (“potential-free circuit”).
An open collector output is a kind of switch. It is mounted on the printed circuit board and provides an output voltage. By varying a resistance value, the status of this output can be influenced. The status is either “grounded” or “floating” (open chain, disconnected). At a high resistance, no current flows through the circuit. The Mobeye software can bring the resistance down to zero, for example after an alarm or incoming command. This causes the output to open. The output voltage on the output is continuous and equal to the external power supply on the Mobeye device (12V). An external device connected to the open collector output can use this 12V voltage as input voltage (max. 200 mA). Use a relay for a heavier device. The open collector output is then used to control the relay. The output does not work with a 6V battery-powered Mobeye device.