Dual motor wireless remote control circuit production

working principle

This article introduces the remote control model dual motor circuit made by TWH9236/38 wireless remote control components, which is used for remote control operation of electric models and electric curtains.

Working Principle Circuit

It consists of the transmitting circuit shown in Figure 1 and the receiving circuit shown in Figure 2. TWH9236/38 is a pair of wireless transmitting/receiving components with built-in antenna, 4 data channels, working frequency of 265MHz, and remote control distance greater than 50m. Generally, the finished TWH9236 transmitting circuit is equipped with a plastic shell, with 4 data input keys (SA-SD) and a power switch (s0 on the side) on the outside. After the power supply voltage is internally stabilized, the E terminal outputs a +5V voltage for data encoding.

The 4-bit parallel input port of TWH9238 is divided into two groups to control two DC motors. A and B control the forward/reverse rotation of the drive motor M1, and C and D control the forward/reverse rotation of the conversion motor M2. The two motors can work at the same time, but the same motor cannot be forward/reverse at the same time, that is, one of A and one of C and D can be input in parallel, but A and B or C and D are not allowed to be input at the same time. For this reason, the original 4 control keys of TWH9236 are removed and replaced with 4 composite keys with only one normally open contact and one normally closed contact, which are connected into two groups of interlocking control circuits to ensure that at any time, only one control key from SA to SD can work, thereby protecting the motor and circuit from damage.

When the power is turned on, the 4-bit parallel output data of the receiving component TwH9238 is cleared, that is, the A~D terminals are all low level, the two output terminals lQ and 2Q of the dual time base circuit NE556 are both high level, and the potentials at both ends of the motor M1 and M2 are equal, so they do not rotate. When the SA key is pressed, the output of the A terminal is high, the B terminal is still low, the lQ of NE556 becomes low, 2Q is still high, and M1 rotates forward; when the SB key is pressed, the B terminal is high, the A terminal is still low, the 1Q of NE556 is high, 2Q is low, and M1 reverses. The operation principle of M2 is similar to this. The relationship between the 4 command keys controlling the model action is shown in the attached table. To stop the motor from rotating, just turn off the power switch So. The IO terminal of TWH9238 is the effective output terminal of receiving decoding, which is actually the VT terminal of the internal digital decoder. The relationship between IO and A-D data output terminals conforms to the logic "OR", that is, as long as one of A-D outputs a high level, 10 will output a positive pulse, and the LED will flash to indicate successful reception. The IO output pulse width is determined by the length of the SA-SD closing time.

Component selection and fabrication

There are 6 pairs of TWH9236/38 series wireless remote control components to choose from. When choosing components, you should make reasonable choices based on the remote control distance and the number of channels required by the model. In general, in addition to the two motors used to control forward, backward, left and right as described in this article, electric models also need whistles or alarms, gunfire, flashes, explosions, left and right turn instructions, etc. Therefore, it is more appropriate to choose TWH9236G/38G with more channels. The drive motors M1 and M2 can be selected as micro DC motors with an operating voltage of 6V and an operating current of less than 200mA (M2 can also be replaced by a conversion electromagnet), and the remaining components are marked as shown in the attached figure.