No-Photo is a ‘camera jammer’ designed for automotive use. No-Photo uses several optical sensors to detect the flash of red-light and speed enforcement cameras. Once a flash is detected, the No-Photo device then flashes it-self causing the photograph from the traffic camera to potentially be over exposed. This device is patented, take a look at the patent here. At the time of writing this, it does not seem like this item is still sold.
The last version of the NoPhoto device was made by Voxx electronics, verses the original manufacturer. Details about the arrangement can be found here.
Opening the noPhoto device was very challenging. The housing was sealed very will. Once the bottom panel was opened the circuit board still could not be removed. The large capacitors on the circuit board were surrounded with potting compound. The capacitors had to be de-soldered from the circuit board, then dug out of the potting compound, and then reattached to the circuit board.
With the circuit board free and capacitors reinstalled, the four layer green circuit board can be seen. The circuit board is laid out in 3 main sections. The right side of the circuit board is the power input and supplies, the middle section is the high-voltage flash circuitry, and the left side contains the microcontroller.
The ECM device is intended to be hardwired into a car. Moving left to right in the image above.
- At the far left is a white silkscreen rectangular where a wire-to-board connector was, until it was damaged due to disassembly.
- Moving to the next component to the right is R38. R38 is a RFE/Fuzetec FSMD500-16-2920R 5A PTC fuse in a 2920 package. Here is a link to the manufacturers product page.
- To the right of the PTC is D12. D12 is a Micro Commercial Components (MCC) S10A diode. This is a standard diode in a DO-214AB (SMC) package. This is most likely used for reverse polarity protection.
- Next to D12 is D31. D31 is a bi-directional diode in a SMA package. Based on the markings and location of the device this appears to be a 17V TVS diode. This diode is connected between the input voltage and ground and is used to suppress voltage transients that could damage other components on the circuit board.
- Next is electrolytic capacitor without a visible silkscreen reference designator. It is labeled as 220uF 25V.
- Moving to the top left corner of the image are two IC’s with the designators of U5 and U6, both in SOT-223 packages. Both of these are 3.3V linear voltage regulators Microchip Technology MCP1804T-3302I/DB.
To the right of U6 is a Linear Tech LT3420 flash capacitor charger IC. This is the 8 pin package labeled U3. Next to U3 is a 1:12 transformer made by Pulse Electronics Power with the part number of PA0367ANLT.
Below the Pulse transformer is another IC in an 8-pin package, this is a Texas Instruments LM25011MY buck regulator. The diode and inductor can be seen to the right of the U13 IC.
In the middle of the circuit board is all of the high-voltage circuitry required to flash the xeon bulb.
To isolate some aspects of the high-voltage there is a Vishay VO2223 Power Phototriac Optocoupler. This is an interesting component I haven’t seen before. This device can switch 600V at nearly 1 amp with 5.3kv of isolation.
Located in the front center of the board is a FT-L4040 flash tube. This is a 50J flash tube, when calculated there is 49J of energy in the capacitors.
To switch the power going to the flash tubes there are a pair of Littelfuse MCR12MG SCRs that are rated for 12A at 600V. There are two of them to let the flash bulb flash twice. The bank of 8 capacitors is actually two banks of four capacitors.
There are 8 United Chemi-Con EKXJ351ELL101MK45S 100uF 350V capacitors in two banks, that provide the energy to flash the xenon bulb twice.
To control the functions of the device there is a Texas Instruments MSP430F2132.
To program and debug the microcontroller there is a Tag Connect footprint to accept a TC2050-IDC-430 cable.
To look for camera flashes the NoPhoto uses four photo-diodes. The photo-diodes used are Vishay BPV23, but its unknown if they are wide or narrow wavelength versions. There does appear to be a footprint for a 5th photo-diode that is not populated in the version I have.
To amplify the signal of the four photo-diodes there are two Analog/Linear LTC6087 dual op-amps. From the op-amps the analog signal is likely then passed to the ADC on the MSP430 microcontroller.